3. Salmonella
Salmonella
Enterobacteria
forma bacilar
Gram‐negativa,
no esporula,
móvil
quimioheterótrof
o, energía de
reacciones de
oxidación y
reducción de
fuentes orgánicas
Anaerobio
facultativo ‐
ATP por
respiración
aeróbica ‐ puede
cambiar a
fermentación
Super‐reino: Bacteria
Reino: Bacteria
Filo: Proteobacteria
Clase: Gammaproteobacteria
Orden: Enterobacteriales
Familia: Enterobacteriaceae
Género: Salmonella
Especies
S. bongori
S. enterica
subesp. enterica *
subesp. salamae
subesp. arizonae
subesp. enterica *
subesp. salamae
subesp. arizonae
subesp. diarizonae
subesp. houtenae
subesp. indica
subesp. diarizonae
subesp. houtenae
subesp. indica
4.
5.
6. Colonización in situ
• Brotes de salmonelosis
relacionados con el
consumo de productos
frescos ha elevado el
interés en las
interacciones
Salmonella‐planta que
permiten la
colonización de la
planta
7. Incubación de Salmonella enterica marcada
con gfp en hojas de lechuga iceberg
• En la luz resultó en la
agragción de bacterias
cerca de los estomas
abiertos e invasión hacia
el tejido de la hoja
• En contracte, la
incubación en la
oscuridad resultó en un
patrón de de adhesión
escasa y muy poca
internalización en los
estomas.
Kroupitski et al. Ap and Env Mic. 2009;75(19):6076–6086.
8. • Estos resultados
implican que el
patógeno es atraído
hacia los nutrientes
recién producidos por
las células activas en
fotosíntesis
Kroupitski et al. Ap and Env Mic. 2009;75(19):6076–6086.
9. Estos hallazgos
• Sugieren la entrada
mecánica de Salmonella
al apoplasto de la planta
• E implica que los
antígenos de Salmonella
no son bien reconocidos
por la inmunidad innata
del estoma, o que este
patógeno ha
evolucionado medios
para evadirla.
10. La internalización en las hojas
• Puede ofrecer una
explicación parcial de la
falla de los sanitizantes
para erradicar
eficientemente los
patógenos de origen
alimentico de las
verduras.
11. En botánica Estoma (en inglés stoma,
plural stomata), del griego “boca”
• Es un poro, encontrado en
la epidermis de las hijas,
tallos y otros órganos que
se utiliza para controlar el
intercambio gaseoso.
• El poro está delimitado por
un par de células
especializadas
[parénquima] conocidas
como células guarda que
son responsables de regular
el tamaño de la apertura
12. Complejo de estomas
• El término también se
emplea colectivamente
para referirse a un
complejo de estomas
completo, tanto el poro
en sí como sus células
guarda.
13. Función de los estomas
• El aire que contiene CO2 y
O2
entra a la planta a través de
estas aperturas
se usa para la respiración y
fotosíntesis,
respectivamente
14. Evolución de los estomas
• El registro fósil aporta poca
información.
• Pueden haber evolucionado
por la modificación de los
conceptáculos de los
ancestros de las plantas
parecidos a algas.
• Conceptáculos: Son
cavidades especializadas de
algas marinas y de agua
dulce que contienen los
órganos reproductores.
Conceptaculos
15. Su ruta evolutiva
• Es claro, sin embargo,
que la evolución de los
estomas pudo ocurrir al
mismo tiempo que la de
la cutícula serosa –
estos dos rasgos
constituyeron una
ventaja muy importante
para las primeras
plantas terrestres.
16. La Salmonella sobrevive sobre o
dentro de los tomates
• Desde la inoculación en la
floración hasta la
maduración.
• El tallo y flores del tomate
son sitios donde la
Salmonella puede adherirse
y permanecer viable
durante el desarrollo del
fruto, y sirve como ruta o
reservorio para la
contaminación del fruto
maduro.
Guo X et al. Ap and Env Mic. 2001;67(10):4760–4764.
17. Reino animal
• La mayoría de los Filos
animales conocidos aparecen
en el registro de fósiles como
especies marinas de cerca de
542 millones de años.
• Los animales están dividios en
varios sub‐grupos, incluidas
las aves, mamíferos, reptiles,
peces e insectos.
22. Sistema de Secreción Tipo III
(TTSS, en inglés)
• Forma principal en la que
Salmonella suministra
factores de virulencia al
hospedero
• Constituído de 20
proteínas
• Ensambladas en orden paso
a paso
• PrgI es una estructura de
aguja extendida por una
base de proteína, forma un
canal hacia el hospedero.
PrgI
23. Islas de patogenicidad de Salmonella
• SPI-1: Invasión
• SPI-2: Replicación
intracelular
• SPI-3: Supervivencia
Intracelular
• SPI-4: Producción de toxinas
• SPI-5: Inflamación
24. Vesícula con Salmonella (VCS)
• Después de la ingestión,
entra una VCS a través de
la endocitosis mediada
por la bacteria
• Vive y se multiplica en la
VCS
• Una forma de evadir la
respuesta inmune del
hospedero
25.
26. Estrés e inmunidad
Los efectos del estrés
sobre el curso de una
infección se han
adjudicado por mucho
tiempo al efecto directo
de las hormonas
relacionadas con el
estrés sobre el sistema
inmune y la fucnión de
la barrera intestinal.
27. Los animales para consumo pueden no tener una vida
libre de estrés, particularmente los que se crían
intensivamente
Quizá lo que fue
inesperado es que la
respuesta al estrés
bacteriano impuesta por
el medio del hospedero
sobre el organismo y la
respuesta de adrenalina
del hospedero impuesta
por la infección pueden
potenciar el crecimiento y
virulencia del
microorganismo.
28. Bacterias— patógeno comensal, obligado u
oportunista
Viven en
estréspermanente y
regulan su expresión de
genes, y, en el caso de
patógenos potenciales,
expresan genes de
virulencia en respuesta
al estrés
medioambiental.
29. • Hace 112 años inició una
nueva era en la
endocrinología con la
primera purificación de
una hormona: adrenalina.
• Desde 1930, casi
inmediatamente después
de su primer uso, se
reportaron casos de
sepsis asociados con la
adrenalina.
Endocrinología Microbiana
30. Endocrinología Microbiana
• La teoría más aceptada para
explicar la habilidad de las
hormonas para influir el curso
de una infección involucra la
supresión del sistema
inmune.
• Hoy, sabemos que los
microorganismos infecciosos
responden igualmente al
medioambiente
neuroendócrino del
hospedero.
31. Adrenalina
1. Incrementa el crecimiento
bacteriano
2. Une proteínas ligadores de
hierro y entonces la bacteria
usa el hierro para crecer.
3. Está involucrada en el quorum
sensing (autoinducción) de las
bacterias
4. Incrementa la expresión de
adhesinas
5. Incrementa virulencia e invasión
32. Detección de Salmonella de
tráquea en avicultura comercial
como herramienta epidemiológica
G. Tellez, G. Kallapura, J.D. Latorre,
L.R. Bielke, A. Menconi, O.B. Faulkner,
A. Wolfenden, and B.M. Hargis
35. transmisión aérea de Salmonella como
fuente de infección cruzada en la avicultura
• Baskerville A., et al. 1992
Airborne infection of laying hens with Salmonella enteritidis phage type 4
• Nakamura M. et al. 1995
• Intratracheal infection of chickens with Salmonella enteritidis and the effect of feed and
water deprivation
• Lever M.S., et al. 1996
Cross‐infection of chicks by airborne transmission of Salmonella enteritidis PT4
• Holt P.S. et al. 1998
Airborne horizontal transmission of Salmonella enteritidis in molted laying chickens
• Gast R.K. et al. 1998
Airborne transmission of Salmonella enteritidis infection between groups of chicks in
controlled‐environment isolation cabinets
• Harbaugh E. 2006
Rapid aerosol transmission of Salmonella among turkeys in a simulated holding‐
shedenvironment
• Basnet H.B., et al. 2008
Reproduction of fowl typhoid by respiratory challenge with Salmonella Gallinarum
36. Desafío Intra‐Traqueal vs.
Intra‐ Saco Aéreo Torácico
• Pollos de 7‐d inoculados IT o
IAS con 105 ufc de S.
Enteritidis (SE).
• Sacrificio 24 h después,
cultivo a partir de tráquea,
tonsilas cecales, hígado y
bazo para recuperación de
SE por enriquecimiento
toda la noche en caldo
tetrationato (CT).
• Las muestra enriquecidas se
sembraron por estría en
agar XLD con novobiocina
(NO) y ácido nalidíxico (NA).
% pollos positivos SE
N=10
37. Transmisión Horizontal
• Sonda oral con ~1x105 SE
(20 % inoculados) @ 3 d
de edad (n=100)
• Pollos mezclados en un
corral (80 % pollos
contacto)
• Sacrificio y cultivo @ 10 d
de edad
0
10
20
30
40
50
60
70
80
90
100
Cecal
Tonsils
Trachea
Challenged
Contacts
% pollos positivos a SE
N=100
38. Prevalencia de Salmonella sp. En tráqueas de pavos
procesados comercialmente
• Toma aséptica de tráquea y
ciegos n=100, pavos
comerciales de 16‐ semanas
de edad
• Las tráques se pinzaron en los
extremos y se agregaron 20 mL
de agua peptona e incubadas 8
h a 37 °C.
• El agua peptona de cada
tráquea se recolectó y
enriqueció con 20 mL de CT 2X
e incubó toda la noche.
• Se sembró por estría en agar
XLD solo con NO.
0
10
20
30
40
50
60
70
80
90
100
E. coli Salmonella sp.
% tráqueas positivas
N=100
34/100 (34 %)
97/100 (97 %)
40. 10^4 10^6 10^8
IT 1,125 3,195 5,114
Oral 1,799 1,858 5,989
0,000
1,000
2,000
3,000
4,000
5,000
6,000
7,000
UFC, Log10 Ciego‐TonsilaCecal
Recuperación de Salmonella Día‐8
Pollos inoculados con Salmonella enteritidis (SE) – 1 semana – Intra‐traqueal u Oral, con 104, 106 o 108
UFC/pollo. Cultivo 24 hrs post desafío. En las barras se expresa el Log10 SE/ gramo de contenido cecal
como promedio ± error estándard P > 0.05. Las literales sobre las barras indican diferencias
significativas P < 0.05
41. Grupo
Log10 SE / gramo de
contenido cecal
Hígado y bazo Tráquea
Ciego ‐ Tonsila
Cecal
Intra‐traqueal ‐ 10^4 1.125 ± 0.401c 6/12 (50%) a 8/12 (66.66%) a 5/12 (41.66%) c
Intra‐traqueal ‐ 10^6 3.195 ± 0.166b 10/12 (83.33%) ab 11/12 (91.66%) ab 12/12 (100%) a
Intra‐traqueal ‐ 10^8 5.114 ± 0.472a 11/12 (91.66%) b 12/12 (100%) b 12/12 (100%) ab
Oral ‐ 10^4 1.799 ± 0.384c 0/12 (0%)c 1/12 (8.33%)c 8/12 (66.66%)b
Oral ‐ 10^6 1.858 ± 0.400c 2/12 (16.66%) c 3/12 (25%)cd 8/12 (66.66%)b
Oral ‐ 10^8 5.989 ± 0.512a 1/11 (9.09%)c 5/11 (45.45%) d 11/11 (100%) ab
Evaluación de la infección Intra‐tracqueal de pollos conSalmonella enteritidis al día 8
Pollos inoculados con Salmonella enteritidis (SE) – 1 semana – Intra‐traqueal u Oral, con 104, 106 o
108 UFC/pollo. Cultivo 24 hrs post desafío. En las barras se expresa el Log10 SE/ gramo de contenido
cecal como promedio ± error estándard. Los datos de tonsilas cecales, tráchea, hígado y bazo se
expresan como pollos positivos/total para cada tejido (%). Literales en la misma columna indican
diferencias significativas, p < 0.05, N=12.
42. Aunque se sabe que el
contacto directo con aves
infectadas y el contacto
indirecto con superficies
medioambientales
contaminadas son factores
importantes en la
diseminación de Salmonella
en las parvadas, el papel
potencial de la transmisión
aerógena no está
claramente definido
46. Los resultados de estos
estudios sugieren que la
tráquea es un órgano viable
para la recuperación de
Salmonella
Reconfirma que el
movimiento aerógeno de
Salmonella en las casetas es
un punto de control relevante
para limitar la diseminación
de la infección dentro de las
parvadas.
49. Recomendaciones para el Control
• Roedores
• Aves silvestres
• Insectos
• Personal
• Fomites
• Medioambiente
• Instalaciones
• Equipo
• Transporte
• Reproductores
• Incubadora
• Entrega
• Parvadas de diferente
origen
• Alimento/Proteína
Animal
• Agua
• Vacunación
• Algunos
probióticos/EC
• Más….
50. Reducción de la Tasa Reproductiva de
casos (R0)
• Prevenir la exposición al patógeno – difícil en el
caso de Salmonella
• Reducir la exposición a nivel incapaz de causar la
infección –difícil pero no imposible en el caso de
Salmonella
• Reducir la tasa de diseminación del
microorganismo al medioambiente (transmisión
horizontal) o de los reproductores a través del
huevo (transmission vertical) disminuye el R0
52. La presión social ha llevado
a la creación de
regulaciones para restringir
el uso de antibióticos en la
producción avícola y la
ganadería.
• Actualmente hay mayor
interés público y científico
respecto a la administración
terapéutica y sub‐
terapéutica de antibióticos
a los animales.
53. Hay necesidad de evaluar el potencial de alternativas a los
antibióticos para mejorar la resitencia a las enfermedades en
la producción animal intensiva.
• Mejorar la resistencia a las
enfermedades de los
animales criados sin
antibióticos no solo
beneficia su salud, bienestar
y eficiencia productiva,
también es una estrategia
clave en el esfuerzo de
mejorar la seguridad
microbiológica de los
productos avícolas.
54. En los últimos 20 años
• Nuestro laboratorio ha
trabajado en la
identificación de candidatos
a probióticos para la
avicultura, los cuales
realmente pueden
desplazar a Salmonella y
otros patógenos entéricos
que han colonizado el tracto
gastrointestinal de pollos y
pollitas.
55. Floramax: Fabricado bajo
licencia exclusiva de la
Universidad de Arkansas
• El trabajo intensivo permitió la
identificación de 11 LAB (del
género o relacionado con
Lactobacillus en el producto
FloraMax B‐11® que fueron
eficaces en el tratamiento de
pollos y pollas infectados con
Salmonella.
56. Vicente, J.S. et al. 2007
J. of Applied Poult. Res. 16: 471‐476.
• La selección de parvadas
infectadas con Salmonella
antes del sacrificio,
demostró que el
tratamiento de dichas
parvadas con B11,
aproximadamente 2
semanas antes del
sacrificio, puede reducir
marcadamente la
recuperación
medioambiental de
Salmonella en pavos y
pollos comerciales.
-
10
20
30
40
50
60
70
80
90
100
Figure 3. Effect of Beneficial Bacteria Alone or in Combination with an
acidifier on Salmonella Isolation in Commercial Turkey Houses
a,b
Control Organic
Acidifier
B11 Acidifier
+ B11
a
a
a
a
PercentSalmonellapositiveswabs
a
Before trt
After trt
a,b
b
c
Ácidos Orgánicos
57. Incremento de la productividad y
reducción de costos de producción
• Ensayos comerciales
de gran escala
indican que la
administración
apropiada de esta
mezcla de
probióticos a pavos y
pollos.
• Vicente J. et al., 2006
• Torres A. et al., 2007
• Torres A. et al., 2007
100
300
500
700
900
1,100
1,300
Initial (11
days of
hatch)
+ 7 d + 14 d + 21 d + 26 d
Age (days)
Bodyweight(g)
Control Probiotic in Drinking Water
Probiotic in Drinking Water + Lactose Probiotic in Feed + Lactose
a a a a
a a
a
b
bb
bbaa
a a
a
b b
b75.6g
124.5g
173.6g
58. Mayor Resistencia a infecciones por
Salmonella spp.
• La extensiva investigación
de laboratorio y de
campo realizados con
este cutivo LAB ha
demostrado el desarrollo
acelerado de la
microbiota normal en
pollos y pavos.
• Tellez G. et al., 2001
• Farnell M. et al., 2006
• Tellez G. et al., 2006
• Vicente J. et al., 2007
• Higgins S. et al., 2007
• Higgins J. et al., 2007
• Wolfenden A., 2008
• Higgins J. et al., 2009
• Vicente J. et al., 2009
• Higgins S., et al., 2011
• Tellez G. et al., 2012
60. Hours post-treatment
6 h 12 h 19 h 24 h
Log10
cfuofSalmonellaenteritidis
0
1
2
3
4
Control
Treated
*
*
*
* Significantly less than control (p<0.05)
67. ¿Porqué es importante tener esa
respuesta immune mucosal?
Estos sitios anatómicos son las principales
áreas de interacción del cuerpo con el
medio externo y con patógenos
potenciales
Ingestión
Inhalación
Inseminación
68. Tejido linfoide asociado a mucosas
–MALT‐
• Difiere fundamentalmente de la respuesta immune
sistémica en:
• El isotipo principal en las secreciones de la mucosa es
la IgA secretoria
• La mayoría de las células productoras de anticuerpos y
linfocitos T efectores están en el MALT
• Sitios linfoides inductor y efector separados
69. El intestine es el órgano inmunológico
más grande en el cuerpo
• Comprende 70‐80% de las
células productoras de
inmunoglobulinas
• Produce más IgA
secretoria (SIgA) (50‐100
mg/kg peso corporal / día)
que la producción total de
IgG en el cuerpo (30
mg/kg/día).
70. Desarrollo de las vacunas mucosales
2006 Nov 2;126(21):2818‐21
• La vacuna active oral
contra la polio fue la
primera mucosal
aceptada para uso
general. Desde
entonces, se han
desarrollado vacunas
similares contra la
fiebre tifoidea, cólera
e infección por
rotavirus.
18a. Dinasty
71. Ventajas de la ruta de inmunización
mucosal
• Induce inmunidad protectora en el sitio de infección
• Induce inmunidad sistémica y mucosal
• Efectiva en presencia de anticuerpos maternos
• No hay reacción de inyección, No necesita agujas
• Fácil administración (vacunas orales combinadas con
el alimento)
72. Incluso si la inmunización mucosal no
elimina totalmente la infección
• Los anticuerpos de la
mucosa limitan el grado
de repicación y
diseminación del
patógeno; por lo tanto,
reduce la carga ambiental
del mismo y minimiza
dramáticamente la tasa de
infección en la parvada y
la transmisión de la
enfermedad.
73. También
• El diseño de sistemas de administración que se
enfoquen en la respuesta immune para conferir una
respuesta balanceada o una que se orientada ya sea
a Th1 o Th2
• Depende del patógeo de interés, se puede dirigir la
respuesta conforme se necesite para maximizar la
protección y reducir las consecuencias de la infección
con la mayoría de los patógenos.
74. Nuevos enfoques
• Identificación de antígenos protectores conservados
(normalmente no inmunogénicos)
• Desarrollo de plataformas efectivas de aplicación mucosal.
75. Moléculas inmuno‐estimulantes CD154 & HMGB1
• CD154
– Glicoproteína Tipo II
– Se une al CD40 en LB & LT activados
CD40 CD154
• HMGB1
– Proteína de Grupo B1 de alta
movilidad.
– Citocina mediadora de la
inflamación
– Se une al TLR4 y activa la
liberación de citocinas de los
macrófagos
76. Nueva tecnología de Adyuvantes
• La modificación de un
polisacárido de origen
natural permite la
adhesion a las células
presentadoras de
antígeno en la mucosa – y
union química a
antígenos autógenos
• Antígenos seleccionados
experimentalmente
ofrecen resultados
alentadores
77. Conclusiones
• En 2014, no hay “balas de plata” disponibles
• Algunos Probióticos dan eficacia y consistencia
similar a la de los antibióticos, y probablemente
mejor que las vacunas disponibles comercialmente.
• Las tecnologías nuevas y emergentes de las vacunas
pueden dar mejoras significativas
• Algunos adyuvantes recientes de actividad mucosal
pueden mejorar la eficacia de las vacunas inactivadas
autógenas.
78. • La producción de
animals para consumo
libres de estrés, en un
medio limpio, puede
tener implicaciones
para prevenir la
adquisición y
transmission potencial
de patógenos de origen
alimentario.
79.
80. Equipo de Integridad Intestinal 2001‐2013
• B. M. Hargis, D.V.M.,Ph.D.
• G.Tellez, D.V.M., Ph.D.
• L. Bielke, Ph.D.
• M. Morgan, Microbiologist
• N. Pumford, Ph.D.
• O. Faulkner, Ph.D.
• A. M. Donoghue, Ph.D.
• D.J. Donoghue, Ph.D.
1. L. Bielke, Ph.D. (2006)
2. A. Torres, Ph.D. (2006)
3. R. Jarquim, MS (2006)
4. J.L. Vicente, Ph.D. (2007)
5. S. Higgins, Ph.D. (2007)
6. J. Higgins, Ph.D. (2007)
7. S. Henderson, MS (2007)
8. F. Solis, Ph.D., (2007)
9. A. Wolfenden, MS (2008)
10. S. Layton, Ph.D. (2009)
11. R. Wolfenden, Ph.D. (2009)
12. G. Gaona, Ph.D. (2009)
13. S. Shivaramaiah, Ph.D. (2011)
1. A. Menconi, Ph.D.
2. J.D. Latorre, Ph.D.
3. G. Kallapura, Ph.D.
4. C. Pixley, Ph.D.
5. A. Wolfenden, Ph.D.
Current Graduate Students
83. Int. J. Poult. Sci., 12 (6): 318-321, 2013
319
63178) for approximately 8 h. The cells were washed 0.5% chitosan (N = 30) for 30s and drained off.
three times with 0.9% sterile saline by centrifugation Control and treated samples were placed in
(1,864 x g) and the approximate concentration of the individual sample bags and kept in a refrigerator at
stock solution was determined spectrophotometrically at 4°C. At 1 h, 24 h, 3, 6, 9 and 12 days, 5 control and
625 nm. The stock solution was serially diluted and 5 treated skin samples were homogenized within
confirmed by colony counts of three replicate samples sterile sample bags using a rubber mallet. Sterile
(0.1 mL/replicate) spread plated on brilliant green agar saline (5 mL) was added to each sample bag and
(BGA, Catalog No. 278820, Becton Dickinson, Sparks, hand stomached. Serial dilutions were spread
MD 21152) plates containing 25 µg/mL novobiocin (NO, plated on MacConkey agar (Becton, Dickinson and
Catalog No. N-1628, Sigma, St. Louis, MO 63178) and Co. Sparks, MD, USA). Each sample was plated as
20 µg/mL NA. triplicate. The plates were incubated at 37°C for 24
Chitosan: Deacetylated 95% food grade chitosan was enumerated respectively. The identification of
obtained commercially (Paragon Specialty Products, individual colonies with different morphology on
LLC Rainsville, AL) and used in all experiments. The MacConkey agar was determined using the API-20E
chitosan molecular weight was 350 kDa with viscosity of test kit for the identification of enteric Gram-negative
800 mPas and particle size of 100 US mesh (sieve size bacteria (BioMerieux, Inc., Hazelwood, MO).
0.152 mm). Chitosan was prepared by dissolving it in a
solution containing 0.5% (w/v glacial acetic acid (Catalog Statistical analysis: The Most Probable Number method
No. J41A08, Mallinckrodt Baker Inc, Phillipsburg, NJ was used to obtain the lowest possible detection limit:
08865). 0.5 log cfu/square cm in the enumeration of ST and
Chicken skin samples: As described by Sarlin et al. bacteria per square cm were converted to log10 numbers
(1998), raw chicken skin was used as an alternative to and analyzed using Analysis of Variance (ANOVA) with
other sampling methods (whole carcass rinse further separation of significantly different means using
procedure, excised skin sampling, or skin swabs) in all Duncan’s Multiple Range test using SAS (SAS Institute,
experiments. Chicken thighs were purchased from a 2002). Significant differences were reported at (p<0.05).
local super market and a strip of skin (approximately 2
by 2 cm) was aseptically collected using forceps and
scissors.
Microbiological procedures:
C Experiment 1: Two trials were conducted. In each
trial, skin samples (N = 20) were dipped into a
phosphate buffered saline (PBS) solution
containing 10 cfu/mL of ST for 30 seconds. Skin8
samples were then removed, drained off and
dipped for an additional 30s into a solution
containing PBS (control; N = 10) or 0.5% chitosan
(N 1 ). Control and treated samples were placed in
individual sample bags and kept in a refrigerator at
4°C. At one or twenty four hours, five control and five
treated samples were removed from the refrigerator
and cultured for ST recovery. Briefly, skin samples
were homogenized within sterile sample bags
using a rubber mallet. Sterile saline (5 mL) was
added to each sample bag and hand stomached.
Serial dilutions were spread plated on BGA plates
containing 25 µg/mL of NO and 20 µg/mL of NA.
Each sample was plated as triplicate. The plates
were incubated at 37°C for 24 h then viable colonies
were observed and enumerated.
C Experiment 2: Skin samples were dipped into a
solution containing either PBS (control; N = 30) or
h and then viable colonies were observed and
aerobic Gram negative bacteria. Colony forming units of
RESULTS AND DISCUSSION
Salmonella is one of the most widespread bacterial
species in poultry and it is often associated with
foodborne illness (Bailey et al., 2002; Lynch et al., 2006).
Cross-contamination by Salmonella in birds and
carcasses may occur during transportation and
processing (Cason et al., 1997; Corrier et al., 1999a).
Therefore, the poultry industry has the challenge of
monitoring and controlling Salmonella at all production
levels (Hargis et al., 1995; Corrier et al., 1999a;
Mikolajczyk and Radkowski, 2002). In the present study,
dipping ST contaminated skin samples for 30 s in a
solution of 0.5% chitosan was able to significantly
reduce the recovery of ST cfu/square cm after 24 h in
both trials (Table 1). The presence of spoilage bacteria
in food products is an important economic problem.
Therefore, an inexpensive and safe treatment to prevent
spoilage is needed. Chitosan has been shown to be an
effective antimicrobial, especially antibacterial. As shown
in Table 2, 0.5% chitosan was effective in reducing total
aerobic mesophilic Gram negative bacteria (spoilage
bacteria) to undetectable levels. The primary spoilage
bacteria in the control group of experiment 2 were
identified as Escherichia coli, Enterobacter aerogenes
and Pseudomonas aeruginosa using the API-20E test kit
for enteric Gram-negative bacteria (bioMerieux, Inc.,
Hazelwood, MO). The concentration of P. aeruginosa in
the control group increased from 7.5 x10 - 1.5x106 8
84. Int. J. Poult. Sci., 12 (6): 318-321, 2013
320
Table 1: Salmonella Typhimurium (log10 cfu±standard error)/square cm of
chicken skin treated with 0.5% chitosan solution in experiment
1
Trial 1 Trial 2
Dipping ---------------------------------- ---------------------------------
treatment 1 h 24 h 1 h 24 h
Control 6.57±0.11 6.03±0.02 6.78±0.06 7.36±0.06a a a a
Chitosan (0.5%) 6.23±0.03 5.81±0.06 7.06±0.08 6.6±0.17a b a b
Values within columns with different lowercase superscripts differ
significantly (p<0.05)
Table 2: Aerobic Gram negative bacteria (log10 cfu±standard
error)/square cm of chicken skin treated with 0.5%
chitosan solution in experiment 2
Sampling time Control Chitosan (0.5%)
1 h 1.31±0.83 Undetectable levelsa
24 h 1.20±0.73 Undetectable levelsa
3 days 4.70±0.31 Undetectable levelsa
6 days 6.25±0.21 Undetectable levelsa
9 days 7.12±0.11 Undetectable levelsa
12 days 8.15±0.11 Undetectable levelsa
Values within columns with different lowercase superscripts differ
significantly (p<0.05)
cfu/square cm from 6-12 days stored at refrigeration
temperatures (data not shown). The decreased growth
as shown in Table 2 indicates that chitosan was very
effective in controlling this and possible other spoilage
bacteria. These results are in agreement with those
published by Darmadji and Izumimoto (1994) who
described the effectiveness of chitosan on storage
stability of minced beef. Solutions of chitosan at 0.5-
1.0% were able to inhibit the growth of spoilage bacteria
on red meat after 10 days of storage at 4°C (Darmadji
and Izumimoto, 1994). The antimicrobial activity and film-
forming characteristic of chitosan makes it a potential
source of food preservative, increasing quality and shelf
life of different types of foods (Darmadji and Izumimoto,
1994; Ouattar et al., 2000; No et al., 2007; Friedman and
Juneja, 2010; Suman et al., 2010; Vargas and Gonzalez-
Martinez, 2010). The mechanism of the antimicrobial
activity of chitosan has not yet been fully elucidated;
nevertheless different hypotheses have been proposed.
The most realistic hypothesis is that chitosan is able to
change cell permeability due to interactions between the
positive charges of its molecules and the negative
charges of the bacterial cell membranes (No et al.,
2007; Friedman and Juneja, 2010). Other hypotheses
include the chelation of metals and essential nutrients,
inhibiting bacterial growth (Rabea et al., 2003). Zheng
and Zhu (2003) had also suggested that high molecular
weight chitosan could be able to form a polymer
membrane around the bacterial cell, preventing it from
receiving nutrients. On the other hand, Zheng and Zhu
(2003) also proposed that the low molecular weight
chitosan could enter the bacterial cell through pervasion,
disrupting the physiological activities of the bacterium.
Conclusion: The results of these experiments suggest
that dipping raw chicken skin in a 0.5% solution of
chitosan can reduce populations of Salmonella
Typhimurium, thus enhancing general food safety and
maybe shelf life of chicken meat. Moreover, these results
also suggest that a solution of 0.5% chitosan can extend
the shelf life of chicken meat as well as cause
decreased growth of Gram negative spoilage bacteria.
Future research will be directed at determining the effect
of these organic compounds on the texture, color,
oxidative stability, pH and consumer acceptance of
chicken meat with treatment combinations that exhibited
the most effective antibacterial activity.
REFERENCES
Bailey, J.S., N.A. Cox, S.E. Craven and D.E. Cosby, 2002.
Serotype tracking of Salmonella through integrated
broiler chicken operations. J. Food Prot., 65: 742-
745.
Byrd, J.A., D.E. Corrier, M.E. Hume, R.H. Bailey, L.H.
Stanker and B.M. Hargis, 1998. Effect of feed
withdrawal on Campylobacter in the crops of
market-age broiler chickens. Avian Dis., 42: 802-
806.
Cason, J.A., J.S. Bailey, N.J. Stern, A.D. Whittemore and
N.A Cox, 1997. Relationship between aerobic
bacteria, Salmonella and Campylobacter on broiler
carcasses. Poult. Sci., 76: 1037-1041.
Chaine, A., E. Arnaud, A. Kondjoyan, A. Collignan and S.
Sarter, 2013. Effect of steam and lactic acid
treatments on the survival of Salmonella Enteritidis
and Campylobacter jejuni inoculated on chicken
skin. Int. J. Food Microbiol., 162: 276-282.
Corrier, D.E., J.A. Byrd, B.M. Hargis, M.E. Hume, R.H.
Bailey and L.H. Stanker, 1999a. Survival of
Salmonella in the crop contents of market-age
broilers during feed withdrawal. Avian Dis., 43: 453-
460.
Corrier, D.E., J.A. Byrd, B.M. Hargis, M.E. Hume, R.H.
Bailey and L.H. Stanker, 1999b. Presence of
Salmonella in the crop and ceca of broiler chickens
before and after preslaughter feed withdrawal.
Poult. Sci., 78: 45-49.
Darmadji, P. and M. Izumimoto, 1994. Effect of chitosan
in meat preservation. Meat Sci., 38: 243-254.
El-Hadrami, A., L.R. Adam, I. El-Hadrami and F. Daayf,
2010. Chitosan in plant protection. Mar. Drugs, 8:
968-987.
Friedman, M. and V.K. Juneja, 2010. Review of
antimicrobial and antioxidative activities of
chitosans in food. J. Food Prot., 73: 1737-1761.
Hargis, B.M., D.J. Caldwell, R.L. Brewer, D.E. Corrier and
J.R. Deloach, 1995. Evaluation of the chicken crop
as a source of Salmonella contamination for broiler
carcasses. Poult. Sci., 74: 1548-1552.
Kong, M., X.G. Chen, K. Xing and H.J. Park, 2010.
Antimicrobial properties of chitosan and mode of
action: a state of the art review. Int. J. Food
Microbiol., 144: 51-63.
85. Int. J. Poult. Sci., 12 (6): 318-321, 2013
321
Lynch, M., J. Painter, R. Woodruff and C. Braden, 2006. Sarlin, L.L., E.T. Barnhart, D.J. Caldwell, R.W. Moore, J.A.
Surveillance for foodborne-disease outbreaks- Byrd, D.Y. Caldwell, D.E. Corrier, J.R. Deloach and
United States, 1998-2002. Centers for Disease B.M. Hargis, 1998. Evaluation of alternative
Control and Prevention. Morbidity and Mortality sampling methods for Salmonella critical control
Weekly Report Surveillance Summaries, 55:1-42. point determination at broiler processing. Poult.
Mikolajczyk, A. and M. Radkowski, 2002. Salmonella Sci., 77: 1253-1257.
spp. on chicken carcasses in processing plants in SAS Institute Inc., 2002. SAS user’s guide: statistics.
Poland. J. Food Prot., 65: 1475-1479. SAS Institute Inc., Cary, N.C.
No, H.K., N.Y. Park, S.H. Lee and S.P. Meyers, 2002. Senel, S. and S.J. McClure, 2004. Potential applications
Antibacterial activity of chitosans and chitosan of chitosan in veterinary medicine. Adv. Drug Deliv.
oligomers with different molecular weights. Int. J. Rev., 56: 1467-1480.
Food Microbiol., 74: 65-72. Singla, A.K. and M. Chawla, 2001. Chitosan: some
No, H.K., S.P. Meyers, W. Prinyawiwatkul and Z. Xu, pharmaceutical and biological aspects-an update.
2007. Applications of chitosan for improvement of J. Pharm. Pharmacol., 53: 1047-1067.
quality and shelf life of foods: A review. J. Food Sci., Suman, S.P., R.A. Mancini, P. Joseph, R. Ramanathan,
72: R87-100. M.K. Konda, G. Dady and S. Yin, 2010. Packaging-
Northcutt, J.K., M.E. Berrang, J.A. Dickens, D.L. Fletcher specific influence of chitosan on color stability and
and N.A. Cox, 2003. Effect of broiler age, feed lipid oxidation in refrigerated ground beef. Meat Sci.,
withdrawal and transportation on levels of coliforms, 86: 994-998.
Campylobacter, Escherichia coli and Salmonella on Tellez, G., C.E. Dean, D.E. Corrier, J.R. Deloach, L.
carcasses before and after immersion chilling. Jaeger and B.M. Hargis, 1993. Effect of dietary
Poult. Sci., 82: 169-173. lactose on cecal morphology, pH, organic acids and
Ouattar, B., R.E. Simard, G. Piett, A. Begin and R.A. Salmonella enteritidis organ invasion in Leghorn
Holley, 2000. Inhibition of surface spoilage bacteria chicks. Poult. Sci., 72: 636-642.
in processed meats by application of antimicrobial Vargas, M. and C. Gonzalez-Martinez, 2010. Recent
films prepared with chitosan. Int. J. Food Microbiol., patents on food applications of chitosan. Recent
62: 139-148. Pat. Food, Nutr. Agric., 2: 121-128.
Petrovich, I., L.A. Grigor'iants, A.N. Gurin and N.A. Gurin, Zhang, L., P. Singh, H.C. Lee and I. Kang, 2013. Effect of
2008. Chitosan: structure, properties, use in hot water spray on broiler carcasses for reduction of
medicine and stomatology. Stomatologiia, 87: 72- loosely attached, intermediately attached and tightly
77. attached pathogenic (Salmonella and
Rabea, E.I., M.E.T. Badawy, C.V. Stevens, G. Smagghe Campylobacter) and mesophilic aerobic bacteria.
and W. Steurbaut, 2003. Chitosan as antimicrobial Poult. Sci., 92: 804-810.
agent: applications and mode of action. Zhao, T., P. Zhao and M.P. Doyle, 2009. Inactivation of
Biomacromolecules, 4: 1457-1465. Salmonella and Escherichia coli O157:H7 on lettuce
Ramirez, G.A., L.L. Sarlin, D.J. Caldwell, Jr.C.R. Yezak, and poultry skin by combinations of levulinic acid
M.E. Hume, D.E. Corrier, J.R. Deloach and B.M. and sodium dodecyl sulfate. J. Food Prot., 72: 928-
Hargis, 1997. Effect of feed withdrawal on the 936.
incidence of Salmonella in the crops and ceca of Zheng, L.Y. and J.F. Zhu, 2003. Study on antimicrobial
market age broiler chickens. Poult. Sci., 76: 654- activity of chitosan with different molecular weights.
656. Carbohydr. Polym., 54: 527-530.
Rose, B.E., W.E. Hill, R. Umholtz, G.M. Ransom and
W.O. James, 2002. Testing for Salmonella in raw
meat and poultry products collected at federally
inspected establishments in the United States,
1998 through 2000. J. Food Prot., 65: 937-947.
87. this may be enough to eliminate Salmonella from most
poultry carcasses, chlorine may bind to organic matter
and be ineffective. In fact, the continued lack of decline
in rates of foodborne illness (MMWR, 2011; Scallan et
al., 2011) indicates that chlorine treatment of carcasses
in the processing facility is not effectively reducing the
incidence of Salmonella contamination. Moreover, fail-
ure to optimize the disinfectant properties of chlorine
(improper pH, concentration, or composition of incom-
ing water) may reduce its efficacy. Chlorine treatment
may also cause offensive and harmful odors due to the
production of chlorine gas and trichloramines (North-
cutt et al., 2005, 2008; Hinton et al., 2007). Because of
these reasons, alternative methods to disinfect poultry
carcass are needed. Studies using organic acids (OA)
to spray or dip poultry carcasses have shown as much
as 3 log10 of Salmonella reduction (Bilgili et al., 1998;
Vasseur et al., 1999; Kubena et al., 2001; Hinton and
Ingram, 2005; Lu et al., 2005; Harris et al., 2006; Van
Immerseel et al., 2006). A specific example was the use
of 2% lactic acid sprayed on chicken carcasses by Yang
et al. (1998), which resulted in a 2 log10 cfu per carcass
reduction of Salmonella.
In this regard, the use of OA may be a viable alterna-
tive to avoid hazards associated with chlorine. There-
fore, the objectives of these studies were to determine
the effects of a mixture of different concentrations of
OA rinse solutions at reducing foodborne pathogens
and spoilage organisms on the surface of contaminated
raw chicken skin during storage at 4°C.
MATERIALS AND METHODS
Chicken Skin Samples
Forceps and scissors were used to aseptically remove
strips of skin (approximately 2 cm × 2 cm) from chick-
en thighs (Sarlin et al., 1998) purchased from a local
supermarket.
Bacterial Strains
A poultry isolate of Salmonella enterica subspecies
enterica serovar Typhimurium was used for all experi-
ments. An enterohemorrhagic Escherichia coli O157:H7
strain, negative for sorbitol fermentation, as well as a
laboratory strain of L. monocytogenes, were obtained
from the Biomass Research Center and USDA Food
Safety Laboratory (University of Arkansas, Fayette-
ville). The amplification and enumeration protocol for
these isolates has previously been described (Tellez et
al., 1993).
Salmonella Typhimurium, E. coli O157:H7,
and L. monocytogenes Culture Preparation
A frozen aliquot of each pathogen was inoculated
into 10 mL of brain heart infusion (BHI) broth (Dif-
co, Sparks, MD) and incubated at 37°C for 24 h in a
shaking incubator (New Brunswick Scientific, Edison,
NJ) at 200 rpm. After 24 h, 10 mL of fresh BHI was
inoculated with 10 μL of this culture, vortexed, and
incubated at 37°C for 18 h at 10 × g to ensure that the
bacterial culture was in the exponential growth phase.
Finally, 10 mL of fresh BHI was inoculated with 20 μL
of the 18 h culture to obtain a concentration of approxi-
mately 108 cfu/mL.
OA Wash Solution
For use in these experiments, mixtures of equal con-
centrations (wt/vol) of acetic (Mallinckrodt Chemicals,
Phillipsburg, NJ), citric (Sigma, St. Louis, MO), and
propionic (Sigma) acids were prepared. All of these ac-
ids are considered generally recognized as safe (GRAS)
and are commonly employed in the food industry
(USDA Food Safety and Inspection Service, 2005).
Experimental Design
Experiment 1. Chicken skin samples were dipped
into a suspension of 108 cfu/mL of Salmonella Ty-
phimurium (n = 20), E. coli O157:H7 (n = 20), or L.
monocytogenes (n = 20) for 30 s. Skin samples were
then removed and dipped into a solution of PBS (con-
trol; n = 30) or an OA wash solution (n = 30) of 0.8%
final concentration of each of the acids for an additional
30 s. Control and treated samples were placed in indi-
vidual sample bags and kept in a refrigerator at 4°C.
At 1 and 24 h, 5 control and 5 treated samples were re-
moved from the refrigerator and cultured separately for
each pathogen. Briefly, skin samples were homogenized
within sterile sample bags using a rubber mallet. Sterile
saline (5 mL) was added to each sample bag and hand
stomached. Serial dilutions were spread plated on bril-
liant green agar (Becton, Dickinson and Co., Sparks,
MD) plates containing 25 μg/mL of novobiocin (Sigma,
St. Louis, MO) and 20 μg/mL of nalidixic acid (Sig-
ma) for Salmonella Typhimurium; MacConkey Sorbitol
Agar for E. coli O157:H7 (Becton, Dickinson and Co.);
or Oxoid Listeria selective agar (EMD Chemicals Inc.,
Gibbstown, NJ) for L. monocytogenes. Each sample was
plated in triplicate. The plates were incubated at 37°C
for 24 h, and viable colonies were observed and enumer-
ated.
Experiment 2. Skin samples (n = 40) were dipped
into a suspension of 106 cfu/mL of Salmonella Ty-
phimurium for 30 s. Skin samples were then removed
and dipped into a solution of PBS (control; n = 10)
or the OA wash solution at 0.2% (n = 10), 0.4% (n
= 10), or 0.6% (n = 10) final concentration of each of
the acids for an additional 30 s. Samples were placed
in individual sample bags and kept in a refrigerator at
4°C. At 1 or 24 h, 5 control and 5 treated samples were
removed from the refrigerator and cultured separately
for Salmonella Typhimurium recovery as described in
experiment 1.
2217BACTERIAL CONTAMINATION OF RAW CHICKEN SKIN
88. Experiment 3. Skin samples (n = 105) were dipped
into a solution of 106 cfu/mL of Salmonella Typhimuri-
um for 30 s. Skin samples were then removed and
dipped into a solution of PBS (control; n = 35) or the
OA wash solution at 0.4% (n = 35) or 0.8% (n = 35)
final concentration of each acid for an additional 30 s.
Control and treated samples were placed in individual
sample bags and kept in a refrigerator at 4°C. At 1
h, 24 h, 3 d, 6 d, 9 d, 12 d, and 15 d, 5 control and 5
treated samples were removed from the refrigerator and
cultured separately for Salmonella Typhimurium recov-
ery as described in experiment 1.
Experiment 4. Skin samples were dipped into a solu-
tion of PBS (control; n = 35) or the OA wash solution
at 0.4% (n = 35) or 0.8% (n = 35) final concentration
of each acid for an additional 30 s. Control and treated
samples were placed in individual sample bags and kept
in a refrigerator at 4°C. At 1 h, 24 h, 3 d, 6 d, 9 d, 12
d, and 15 d 5 control and 5 treated skin samples were
homogenized within sterile sample bags using a rub-
ber mallet. Sterile saline (5 mL) was added to each
sample bag and hand stomached. Serial dilutions were
spread plated on tryptic soy agar (Becton Dickinson
and Co.) and MacConkey agar (Becton, Dickinson and
Co.). Each sample was plated in triplicate. The plates
were incubated at 37°C for 24 h, and viable colonies
were observed and enumerated. Bacterial identification
of different morphology colonies that grew on MacCo-
nkey agar was determined using the API-20E test kit
for the identification of enteric gram-negative bacteria
(bioMerieux Inc., Hazelwood, MO).
Statistical Analysis
In all experiments, for each foodborne pathogen or
psychotropic bacteria, the cfu/skin section in control or
treated group, respectively, was analyzed using ANO-
VA with further separation of significantly different
means using Duncan’s multiple range test using SAS
(SAS Institute Inc., 2002). Significant differences were
reported at P < 0.05.
RESULTS
Table 1 summarizes the effect of 0.8% OA wash so-
lution on chicken skin inoculated with Salmonella Ty-
phimurium, E. coli O157:H7, or L. monocytogenes in
experiment 1. The OA wash solution caused a 3.8 and
3.2 cfu/skin section log10 reduction in presumptive
Salmonella Typhimurium and E. coli O157:H7, respec-
tively, 1 h after cold storage. By 24 h, no Salmonella
Typhimurium or E. coli O157:H7 were recovered from
treated samples. For presumptive L. monocytogenes,
there was a 1.85 and 2.87 cfu/skin section log10 reduc-
tion at 1 and 24 h, respectively.
Table 2 summarizes the results of 3 additional con-
centrations (0.2, 0.4, or 0.6%) of the same OA wash
solution used as a sanitizing dip for raw chicken skin
samples inoculated with Salmonella Typhimurium. All
3 concentrations were able to significantly reduce pre-
sumptive Salmonella Typhimurium at both 1 and 24 h
of storage, and no Salmonella Typhimurium were re-
covered from skin dipped in 0.6% solutions after 24 h
of storage. However, 0.6% OA mixture solution showed
complete bactericidal activity against Salmonella Ty-
phimurium by 24 h.
Table 3 summarizes the effect of the OA wash so-
lution at a concentration of 0.4 or 0.8% on Salmo-
nella Typhimurium skin rinse in experiment 3. At 1
h posttreatment, the 0.8% OA wash solution signifi-
cantly reduced (P < 0.05) presumptive Salmonella Ty-
phimurium cfu by 1.72 cfu/skin section log10 compared
with control skin samples, whereas at a concentration
of 0.4%, there was a numerical decrease in presump-
tive Salmonella Typhimurium cfu (P > 0.05). However,
both OA mixtures significantly reduced total presump-
tive Salmonella Typhimurium cfu recovered at all other
storage times (24 h, 3 d, 6 d, 9 d, 12 d, and 15 d). In
all samples treated with either concentration of the OA
wash solution, Salmonella was not detected at d 9, 12,
and 15 posttreatment. In contrast, control skin samples
Table 1. Experiment 1: effect of rinsing chicken skin with an organic acid mixture (OAM) on recovery of presumptive Salmonella
Typhimurium, Escherichia coli O157:H7, and Listeria monocytogenes1
Time of
sampling (h)
Control
Salmonella
Typhimurium
OAM
Salmonella
Typhimurium
Control
E. coli
O157:H7
OAM
E. coli
O157:H7
Control
L. monocytogenes
OAM
L. monocytogenes
1 6.0 ± 0.07a 2.20 ± 0.75b 7.57 ± 0.10a 4.32 ± 0.24b 7.39 ± 0.01a 5.54 ± 0.13b
24 6.90 ± 0.04a 0 ± 0b 7.12 ± 0.09a 0 ± 0b 7.21 ± 0.09a 4.34 ± 0.44b
a,bValues within rows for control or treated group for each foodborne pathogen, respectively, with different lowercase superscripts differ significantly
(P < 0.05).
1Data expressed as log10 cfu/skin section mean ± SE. OAM = 0.8% acetic acid, 0.8% citric acid, and 0.8% propionic acid.
Table 2. Experiment 2: effect of 3 different concentrations of
an organic acid mixture (OAM) rinse solutions on chicken skin
inoculated with Salmonella Typhimurium1
Treatment 1 h 24 h
Control PBS 6.8 ± 0.04a,x 6.2 ± 0.09a,x
0.2% OAM 5.5 ± 0.18b,x 2.08 ± 1.2b,y
0.3% OAM 4.6 ± 0.09c,x 1.4 ± 0.87b,y
0.4% OAM 4.6 ± 0.17c,x 0.0 ± 0.0c,y
a–cValues within treatment columns, or x,yvalues within time of evalu-
ation rows for each treatment with different superscripts differ signifi-
cantly (P < 0.05).
1Data expressed as log10 cfu/skin section mean ± SE. OAM = acetic
acid, citric acid, and propionic acid.
2218 Menconi et al.
89. showed a numerical increase in Salmonella Typhimuri-
um cfu at each day of sampling (Table 3).
The results of experiment 4, the effect of 0.4 or 0.8%
OA wash solutions on total aerobic bacterial cfu skin
section of chicken skin are summarized in Table 4. On
tryptic soy agar, after 1 h of cold storage, the total
number of aerobic bacteria detected was low in the con-
trol samples. However, in both OA wash solutions, no
bacteria were detected at this time of evaluation. At all
other times of evaluation, control samples showed an
increase in total cfu/skin section of chicken skin with
a sharp increase between 3 and 6 d poststorage and
was significantly different (P < 0.05) from both treated
groups. Compared with control samples, the 0.4% OA
wash solution showed a significant reduction (P < 0.05)
in total cfu/skin section at 24 h and 3 d poststorage. At
6, 9, 12, and 15 d, no aerobic bacteria were recovered
from skin samples treated with the 0.4% OA wash solu-
tion. Interestingly, at all times of evaluation, no aerobic
bacteria were recovered from skin samples treated with
the 0.8% OA wash solution (Table 4).
Samples from both control and treated bags were
plated on MacConkey agar for the detection of gram-
negative bacteria associated with food spoilage. Both
OA wash solutions inhibited to not detectable levels the
growth of gram-negative bacteria at all times of evalu-
ation. However, bacteria were recovered from the 24 h
samples and these numbers increased exponentially in
the control samples to levels that were too numerous
to count at d 9, 12, and 15, being Escherichia ssp.,
Enterobacter spp., and Pseudomonas spp. among the
predominant bacterial flora on the broiler skin (data
not shown).
DISCUSSION
In general, carcass rinse applications that decrease
Salmonella by 2 log10 cfu/mL are considered effective
because most carcasses are considered to have about
100 Salmonella cells (Jetton et al., 1992). Lactic acid
and citric acid at concentrations of 1 to 3% have been
shown to reduce E. coli O157:H7, Salmonella serotypes,
and L. monocytogenes when sprayed on beef and poul-
try carcasses by causing intracellular acidification (Vas-
seur et al., 1999). According to Vasseur et al. (1999),
citric acid showed to have the highest inhibitory effect
because of its ability to diffuse through the cell mem-
brane. In the same experiment, lactic acid decreased
the ionic concentration within the bacterial cell mem-
brane, leading to accumulation of acid within the cell
cytoplasm, disruption of the proton motive force, and
inhibition of substrate transport (Vasseur et al., 1999).
In these experiments, the blend of OA wash solution
showed significant antibacterial activity against 3 food-
borne pathogens commonly implicated in meat process-
ing (Table 1). Additionally, we also found that lower
concentrations of the OA wash solution are almost as
effective as higher concentrations, and based on these
experiments, we conclude that a concentration of 0.4%
demonstrates optimum antibacterial/bactericidial ac-
tivity (Tables 2, 3, and 4). Furthermore, the OA wash
solution, when used at a concentration of 0.4%, was able
Table 3. Experiment 3: effect of 2 different concentrations of an organic acid mixture (OAM) rinse
solution on chicken skin inoculated with Salmonella Typhimurium1
Sample time Control PBS 0.4% OAM 0.8% OAM
1 h 3.37 ± 0.20a,x 2.01 ± 0.83ab,x 1.65 ± 1.05b,x
24 h 3.55 ± 0.30a,x 1.26 ± 0.77bc,x 0 ± 0c,x
3 d 3.31 ± 0.30a,x 0 ± 0b,x 0.60 ± 0.60b,x
6 d 3.40 ± 0.31a,x 0.60 ± 0.60b,x 0 ± 0b,x
9 d 3.49 ± 0.33a,x 0 ± 0b,x 0 ± 0b,x
12 d 4.89 ± 0.32a,y 0 ± 0b,x 0 ± 0b,x
15 d 6.82 ± 0.15a,y 0 ± 0b,x 0 ± 0b,x
a–cValues within treatment rows, or x,yvalues within time of evaluation column for each treatment with different
superscripts differ significantly (P < 0.05).
1Data expressed as log10 mean ± SE. OAM = acetic acid, citric acid, and propionic acid.
Table 4. Experiment 4: effect of 2 different concentrations of organic acid mixture (OAM) rinse solu-
tions on total cfu/skin section of chicken skin plated on tryptic soy agar plates
Sample time Control PBS 0.4% OAM 0.8% OAM
1 h 0.60 ± 0.60a,x 0 ± 0b 0 ± 0b,x
24 h 1.62 ± 0.66a,x 0.60 ± 0.60ab,y 0 ± 0b,x
3 d 4.49 ± 0.39a,y 2.45 ± 1.51b,x 0 ± 0c,x
6 d 7.03 ± 0.37a,z 0 ± 0b,y 0 ± 0b,x
9 d 7.26 ± 0.19a,z 0 ± 0b,y 0 ± 0b,x
12 d 7.61 ± 0.23a,z 0 ± 0b,y 0 ± 0b,x
15 d 7.99 ± 0.27a,z 0 ± 0b,y 0 ± 0b,x
a–cValues within treatment rows, or x–zvalues within time of evaluation column for each treatment with different
superscripts differ significantly (P < 0.05).
1Data expressed as log10 mean ± SE. OAM = acetic acid, citric acid, and propionic acid.
2219BACTERIAL CONTAMINATION OF RAW CHICKEN SKIN
90. to prevent recovery of aerobic food-spoilage bacteria up
to 2 wk of storage at 4°C, indicating that one wash
with this solution may enhance shelf-life of packaged
meat significantly. Overall, the results of these experi-
ments suggest that dipping raw chicken skin in an OA
wash solution of citric, lactic, and propionic acids can
greatly reduce populations of pathogenic bacteria, thus
enhancing overall food safety and shelf life of chicken
meat. Poultry meat quality is a concern when using
different OA washes. In an earlier study, the quality
effects of acetic, citric, lactic, malic, mandelic, or tar-
taric acids at 0.5, 1, 2, 4, and 6% concentrations were
tested on broiler carcasses, revealing that in simulated
dip application, each of the acids decreased lightness
and increased redness and yellowness values in the skin
of broiler carcasses with increasing acid concentration
(Bilgili et al., 1998). Therefore, future research will be
directed at determining the effect of these OA on the
texture, color, oxidative stability, pH, and consumer ac-
ceptance of chicken meat with treatment combinations
that exhibited the most effective antibacterial activity.
REFERENCES
Bilgili, S. F., D. E. Conner, J. L. Pinion, and K. C. Tamblyn. 1998.
Broiler skin color as affected by organic acids: Influence of con-
centration and method of application. Poult. Sci. 77:752–757.
Bourassa, D. V., D. L. Fletcher, R. J. Buhr, M. E. Berrang, and
J. A. Cason. 2004. Recovery of salmonellae from trisodium
phosphate-treated commercially processed broiler carcasses after
chilling and after seven-day storage. Poult. Sci. 83:2079–2082.
Dickson, J. S., G. R. Siragusa, and J. E. Wray Jr. 1992. Predicting
the growth of Salmonella Typhimurium on beef by using the
temperature function integration technique. Appl. Environ. Mi-
crobiol. 58:3482–3487.
Harris, K., M. F. Miller, G. H. Loneragan, and M. M. Brashears.
2006. Validation of the use of organic acids and acidified so-
dium chlorite to reduce Escherichia coli O157 and Salmonella
Typhimurium in beef trim and ground beef in a simulated pro-
cessing environment. J. Food Prot. 69:1802–1807.
Hinton, A., Jr., and K. D. Ingram. 2005. Microbicidal activity of tri-
potassium phosphate and fatty acids toward spoilage and patho-
genic bacteria associated with poultry. J. Food Prot. 68:1462–
1466.
Hinton, A., Jr., J. K. Northcutt, D. P. Smith, M. T. Musgrove,
and K. D. Ingram. 2007. Spoilage microflora of broiler carcasses
washed with electrolyzed oxidizing or chlorinated water using an
inside-outside bird washer. Poult. Sci. 86:123–127.
Jetton, J. P., S. F. Bilgili, D. E. Conner, J. S. Kotrola, and M. A.
Reiber. 1992. Recovery of salmonellae from chilled broiler car-
casses as affected by rinse media and enumeration method. J.
Food Prot. 55:329–332.
Kubena, L. F., J. A. Byrd, C. R. Young, and D. E. Corrier. 2001. Ef-
fects of tannic acid on cecal volatile fatty acids and susceptibility
to Salmonella typhimurium colonization in broiler chicks. Poult.
Sci. 80:1293–1298.
Laury, A. M., M. V. Alvarado, G. Nace, C. Z. Alvarado, J. C.
Brooks, A. Echeverry, and M. M. Brashears. 2009. Validation of
a lactic acid- and citric acid-based antimicrobial product for the
reduction of Escherichia coli O157: H7 and Salmonella on beef
tips and whole chicken carcasses. J. Food Prot. 72:2208–2211.
Lu, Z., J. G. Sebranek, J. S. Dickson, A. F. Mendonca, and T. B.
Bailey. 2005. Application of predictive models to estimate Liste-
ria monocytogenes growth on frankfurters treated with organic
acid salts. J. Food Prot. 68:2326–2332.
Lynch, M., J. Painter, R. Woodruff, C. Braden, and Centers for Dis-
ease Control and Prevention. 2006. Surveillance for foodborne-
disease outbreaks—United States, 1998–2002. MMWR Surveill.
Summ. 55:1–42.
MMWR (Morbidity and Mortality Weekly Report). 2011. Vol. 60,
No. 22. Accessed Jun. 16, 2011. http://www.cdc.gov/mmwr.
Mountney, G. J., and J. O’Malley. 1965. Acids as poultry meat pre-
servatives. Poult. Sci. 44:582–586.
Northcutt, J. K., M. E. Berrang, J. A. Dickens, D. L. Fletcher, and
N. A. Cox. 2003. Effect of broiler age, feed withdrawal, and trans-
portation on levels of coliforms, Campylobacter, Escherichia coli
and Salmonella on carcasses before and after immersion chilling.
Poult. Sci. 82:169–173.
Northcutt, J. K., D. Smith, R. I. Huezo, and K. D. Ingram. 2008.
Microbiology of broiler carcasses and chemistry of chiller water as
affected by water reuse. Poult. Sci. 87:1458–1463. http://dx.doi.
org/10.3382/ps.2007-00480.
Northcutt, J. K., D. P. Smith, M. T. Musgrove, K. D. Ingram, and
A. Hinton Jr. 2005. Microbiological impact of spray washing
broiler carcasses using different chlorine concentrations and wa-
ter temperatures. Poult. Sci. 84:1648–1652.
Parveen, S., M. Taabodi, J. G. Schwarz, T. P. Oscar, J. Harter-
Dennis, and D. G. White. 2007. Prevalence and antimicrobial
resistance of Salmonella recovered from processed poultry. J.
Food Prot. 70:2466–2472.
Ramirez, G. A., L. L. Sarlin, D. J. Caldwell, C. R. Yezak Jr., M. E.
Hume, D. E. Corrier, J. R. Deloach, and B. M. Hargis. 1997. Ef-
fect of feed withdrawal on the incidence of Salmonella in the crops
and ceca of market age broiler chickens. Poult. Sci. 76:654–656.
Sarlin, L. L., E. T. Barnhart, D. J. Caldwell, R. W. Moore, J. A.
Byrd, D. Y. Caldwell, D. E. Corrier, J. R. Deloach, and B. M.
Hargis. 1998. Evaluation of alternative sampling methods for Sal-
monella critical control point determination at broiler processing.
Poult. Sci. 77:1253–1257.
SAS Institute Inc. 2002. SAS User’s Guide: Statistics. SAS Institute
Inc., Cary, NC.
Scallan, E., R. M. Hoekstra, F. J. Angulo, R. V. Tauxe, M. A. Wid-
dowson, S. L. Roy, J. L. Jones, and P. M. Griffin. 2011. Food-
borne illness acquired in the United States—Major pathogens.
Emerg. Infect. Dis. 17:7–15.
Tellez, G., C. E. Dean, D. E. Corrier, J. R. Deloach, L. Jaeger, and
B. M. Hargis. 1993. Effect of dietary lactose on cecal morphology,
pH, organic acids, and Salmonella enteritidis organ invasion in
Leghorn chicks. Poult. Sci. 72:636–642.
USDA Food Safety and Inspection Service. 2005. FSIS Directive
7120.1 Amendment 5: Safe and suitable ingredients used in
the production of meat and poultry products. Accessed Jan. 5,
2009. http://www.fsis.usda.gov/OPPDE/rdad/FSISDirectives/
7120.1_Amend_5.pdf.
Van Immerseel, F., J. B. Russell, M. D. Flythe, I. Gantois, L. Tim-
bermont, F. Pasmans, F. Haesebrouck, and R. Ducatelle. 2006.
The use of organic acids to combat Salmonella in poultry: A
mechanistic explanation of the efficacy. Avian Pathol. 35:182–
188. http://dx.doi.org/10.1080/03079450600711045.
Vasseur, C., L. Baverel, M. Hebraud, and J. Labadie. 1999. Ef-
fect of osmotic, alkaline, acid or thermal stresses on the growth
and inhibition of Listeria monocytogenes. J. Appl. Microbiol.
86:469–476.
Yang, Z., Y. Li, and M. Slavik. 1998. Use of antimicrobial spray
applied with an inside-outside birdwasher to reduce bacterial
contamination on prechilled chicken carcasses. J. Food Prot.
61:829–832.
Zhao, T., P. Zhao, and M. P. Doyle. 2009. Inactivation of Salmo-
nella and Escherichia coli O157:H7 on lettuce and poultry skin
by combinations of levulinic acid and sodium dodecyl sulfate. J.
Food Prot. 72:928–936.
2220 Menconi et al.
92. Int. J. Poult. Sci., 12 (2): 72-75, 2013
73
Salmonella determined by spread plating were reported In experiment 2, 80 day-of-hatch broiler chicks were
as the concentration of Salmonella (in cfu/mL) for in vitro
experiments and total colony-forming units for in vivo
challenge experiments.
Experimental Design - in vitro crop assay: An assay
previously described (Barnhart et al., 1999) was used
with modifications. Briefly, 1.25g of unmedicated chick
starter feed was measured into 13×100 mm borosilicate
tubes and autoclaved. The feed was suspended in 4.5
mL sterile saline and inoculated with 0.5 mL of a
Salmonella Typhimurium culture containing
approximately 10 cfu/mL. The tubes were treated with4
either: 1) saline as a control; 2) OAM, having a final
concentration of acetic, citric and propionic acids at
0.031 % or; 3) OAM, having a final concentration of
acetic, citric and propionic acids at 0.062 %. Each
sample was run as triplicate, each treatment had 5
replicates, and the entire assay was repeated in 2
additional trials. After administering the treatment, the
tubes were vortexed and incubated at 37EC for 30
minutes and an additional 6 h. The tubes were then
agitated and 20 µL of the content was serially diluted
and plated as triplicates on BGA containing novobiocin
and nalidixic acid. Typical ST colonies were counted
after 24 h of incubation.
Experimental design with chickens: In experiment 1, 64
day-of-hatch broiler chicks were obtained from a local
hatchery. Chicks were randomized and challenged with
2 x 10 cfu/mL of ST. The chicks were then held in chick5
boxes for 1 h and then randomly assigned to 1)
untreated control or continuous treatment in the drinking
water with: 2) Optimizer at commercial recommended®
doses; 3) OAM, having a final concentration of acetic,
citric and propionic acids at 0.031 % or; 4) OAM, having
a final concentration of acetic, citric and propionic acids
at 0.062%. Chicks were housed in brooder batteries with
food and water ad libitum. At 24 hr post-challenge,
chicks were humanely killed by CO inhalation and crop,2
both ceca and cecal tonsils were aseptically harvested
separately. Salmonella recovery procedures have been
previously described by our laboratory and were followed
with some modifications (Tellez et al., 1993). Briefly, crop
and cecal tonsils were enriched in 10 mL of tetrathionate
broth overnight at 37EC. Following enrichment, each
sample was streaked for isolation on BGA plates
containing 25 µg/mL NO and 20 µg/mL NA. The plates
were incubated at 37EC for 24 h and examined for the
presence or absence of the antibiotic resistant ST. Ceca
were weighed and then homogenized within sterile
sample bags using a rubber mallet. Sterile saline (4X5
weight to volume) was added to each sample bag and
hand stomached with the cecal contents. Dilutions were
spread plated on BGA plates containing 25 g/mL NO
and 20 µg/mL NA. The plates were incubated at 37EC for
24 h and cfu of ST per ceca were determined.
obtained from a local hatchery. Chicks were randomized
and challenged with 2 x 10 cfu/mL of ST. The chicks5
were then held in chick boxes for 1 h and then randomly
assigned to 1) untreated control or continuous treatment
in the drinking water with: 2) Optimizer® at commercial
recommended doses; 3) OAM, having a final
concentration of acetic, citric and propionic acids at
0.031 % or; 4) OAM, having a final concentration of
acetic, citric and propionic acids at 0.062 %. Chicks were
housed in brooder batteries with food and water ad
libitum. At 24 hr post-challenge, chicks were humanely
killed by CO inhalation and crops were aseptically2
harvested, weighed and were homogenized within
sterile sample bags using a rubber mallet. Sterile saline
(4X weight to volume) was added to each sample bag
and hand stomached with the crop contents. Dilutions
were spread plated on BGA plates containing 25 µg/mL
NO and 20 µg/mL NA. The plates were incubated at
37EC for 24 h and cfu of ST per crop were determined.
Following this, crops were enriched with a 2X solution of
tetrathionate broth overnight at 37EC. Following
enrichment, each sample was streaked for isolation on
BGA plates containing 25 µg/mL NO and 20 µg/mL NA.
The plates were incubated at 37EC for 24 h and
examined for the presence or absence of the antibiotic
resistant ST.
Statistical analysis: The incidence of Salmonella
recovery within experiments was compared using the
chi-square test of independence (Zar, 1984) testing all
possible combinations to determine significant (P<0.05)
differences between control and treated groups. Cecal
cfu data were converted to log10 cfu numbers and then
compared using the GLM procedure of SAS (SAS
Institute, 2002) with significance reported at P < 0.05.
RESULTS AND DISCUSSION
Salmonella colonization of poultry flocks can occur via
horizontal transmission (Bailey et al., 2002; Kim et al.,
2007; Alali et al., 2010; Vandeplas et al., 2010). Once
cecal tonsil colonization is established, the bacterium is
consistently shed in the feces (Bailey et al., 2002; Foley
et al., 2008). Feed Withdrawal induces pecking of the
contaminated litter which may contaminate the crop
(Corrier et al., 1999c) and if the crop is ruptured during
processing, Salmonella may contaminate raw poultry
products (Corrier et al., 1999b). Because the crop is
more likely to rupture than the ceca, the crop represents
an important source of Salmonella contamination to
carcasses (Hargis et al., 1995; Corrier et al., 1999a).
Table 1 summarizes the results of effect of OAM on ST in
an in vitro crop assay. In 3 independent trials, the
0.031% OAM reduced ST by 6 h and the 0.062 % OAM
was also efficacious. However, when 0.062 % OAM was
tested in chickens, it had a similar effect as Optimizer®
showing a significant reduction in total number of ST
93. Int. J. Poult. Sci., 12 (2): 72-75, 2013
74
Table 1: Effect of organic acid mix (OAM) on Salmonella Typhimurium (ST) in an in vitro crop assay
Trial 1 Trial 2 Trial 3
------------------------------------------- ------------------------------------------- -------------------------------------------
30 minutes 6 hours 30 minutes 6 hours 30 minutes 6 hours
Control (ST) 6.25±0.13 7.09±0.09 7.42±0.03 7.07±0.04 4.95±0.13 5.99±0.22a a a a a a
0.031% OAM 6.08±0.8 5.98±0.01 7.43±0.03 5.86±0.03 4.88±0.24 4.56±0.07a b a b a b
0.062% OAM ND ND 7.39±0.04 6.24±0.12 4.70±0.22 4.56±0.07a b b b
Organic acids mix= acetic, citric, and propionic acid. ND= Not determined. Data are expressed as log mean ± standard error.10
Values within columns with different lowercase superscripts differ significantly (P < 0.05).
Table 2: Experiment 1, effect of Optimizer or organic acids mix (OAM)®
on Salmonella Typhimurium (ST) infection in broiler chicks
during 24 hours period
Crop Cecal tonsils Log ST/gram10
Enrichment Enrichment of ceca
Treatment culture culture content
Control ST 15/16 (94%) 14/16 (87%) 2.43±0.35a
Optimizer 13/16 (81%) 3/16 (19%) ** 0.22±0.22® b
0.031% OAM 16/16 (100%) 12/16 (75%) 2.02±0.35a
0.062% OAM 13/16 (81%) 8/16 (50%) * 1.34±0.40a
Organic acids mix= acetic, citric, and propionic acid. Data of enrichment
culture is expressed as positive/total chickens for each tissue sampled
(%). * Indicates significant difference at P < 0.05. ** Indicates
significant difference at P < 0.001.
Log ST/gram of ceca content data is expressed as mean ± standard10
error. Values within columns with different lowercase superscripts differ
significantly (P < 0.05).
Table 3: Experiment 2, effect of Optimizer or organic acids mix®
(OAM) on Salmonella Typhimurium (ST) infection in
broiler chicks during 24 hours period
Crop Log ST/gram10
enrichment of crop
Treatment culture content
Control ST 20/20 (100%) 5.21 ± 0.31a
Optimizer 18/20 (90%) 3.73 ± 0.25® b
0.031% OAM 20/20 (100%) 3.96 ± 0.37b
0.062% OAM 18/20 (90%) 3.89 ± 0.22b
Organic acids mix= acetic, citric, and propionic acid
Data of enrichment culture is expressed as positive/total chickens
for each tissue sampled (%).
Log ST / gram of crop content is expressed as mean ± standard10
error. Values within columns with different lowercase superscripts
differ significantly (P < 0.05).
positive chickens in cecal tonsils (Table 2), and reducing
the number of ST in the crop (Table 3) when compared
with controls.
In the present study, Optimizer® reduced ST colonization
in both crop and ceca (Tables 2 and 3) as has been
previously reported (Jarquin et al., 2007; Wolfenden et
al., 2007). In experiment 1, treatment with OAM in the
drinking water caused a significant reduction (P<0.05) in
ST recovery from cecal tonsils when compared with the
controls (OA treated = 19% vs. controls = 87%). Also,
treatment with OAM reduced 2.21 logs of ST when
compared with controls (Table 2). While any of the
treatments reduced recovery of ST from the crop by
enrichment, all treatments reduced the number of ST
recovered from crop content at 24 h (Table 3). The
organic acids used in this study (citric, acetic and
propionic) as well as others have been shown to be
individually effective in reducing Salmonella in vitro (Van
Immerseel et al., 2006). The biocidal efficacy and the
effect on virulence of Salmonella differ with each organic
acid treatment and each organic acid has a unique effect
on bacteria normally present in the crop and
gastrointestinal tract (Furuse et al., 1991; Byrd et al.,
2001; Castro Gonzalez et al., 2001; Kubena et al., 2001).
Characteristics of organic acids such as chain length,
side chain composition, pkA values and hydrophobicity
could be factors that effect biocidal activity (Van
Immerseel et al., 2006). For these reasons, a mixture of
organic acids was tested to reduce ST crop
contamination. Further studies are being conducted to
evaluate these new formulations of OAM during the pre-
slaughter feed withdrawal period in commercial
chickens to evaluate water consumption and bactericidal
activity against Salmonella in the crop.
REFERENCES
Alali, W.Q., S. Thakur, R.D. Berghaus, M.P. Martin and
W.A. Gebreyes, 2010. Prevalence and Distribution of
Salmonella in Organic and Conventional Broiler
Poultry Farms. Foodborne Pathog. Dis.
Bailey, J.S., N.A. Cox, S.E. Craven and D.E. Cosby, 2002.
Serotype tracking of Salmonella through integrated
broiler chicken operations. J. Food Prot., 65: 742-
745.
Barnhart, E.T., L.L. Sarlin, D.J. Caldwell, J.A. Byrd, D.E.
Corrier and B.M. Hargis, 1999. Evaluation of
potential disinfectants for preslaughter broiler crop
decontamination. Poult. Sci., 78: 32-37.
Byrd, J.A., B.M. Hargis, D.J. Caldwell, R.H. Bailey, K.L.
Herron, J.L. McReynolds, R.L. Brewer, R.C.
Anderson, K.M. Bischoff, T.R. Callaway and L.F.
Kubena, 2001. Effect of lactic acid administration in
the drinking water during preslaughter feed
withdrawal on Salmonella and Campylobacter
contamination of broilers. Poult. Sci., 80: 278-283.
Castro Gonzalez, M.I., S. Montano Benavides and F.
Perez-Gil Romo, 2001. Fatty acids in sardine
canned in tomato sauce from different fishing areas
of the Mexican Pacific. Arch. Latinoam. Nutr., 51:
400-406.
Corrier, D.E., J.A. Byrd, B.M. Hargis, M.E. Hume, R.H.
Bailey and L.H. Stanker, 1999a. Survival of
Salmonella in the crop contents of market-age
broilers during feed withdrawal. Avian Dis., 43: 453-
460.
Corrier, D.E., J.A. Byrd, B.M. Hargis, M.E. Hume, R.H.
Bailey and L.H. Stanker, 1999b. Survival of
Salmonella in the crop contents of market-age
broilers during feed withdrawal. Avian Dis., 43: 453-
460.
94. Int. J. Poult. Sci., 12 (2): 72-75, 2013
Catalog No. N-4382, Sigma, St. Louis, MO 63178 USA1
Catalog No. 211822, Becton Dickinson and Co., Sparks, MD 21152 USA2
Catalog No. 278820, Becton Dickinson, Sparks, MD 21152 USA3
Catalog No. N-1628, Sigma, St. Louis, MO 63178 USA4
Catalog No. B00679WA, Nasco, Fort Atkinson, WI 53538-09015
75
Corrier, D.E., J.A. Byrd, B.M. Hargis, M.E. Hume, R.H. Van Immerseel, F., J.B. Russell, M.D. Flythe, I. Gantois,
Bailey, and L.H. Stanker, 1999c. Presence of L. Timbermont, F. Pasmans, F. Haesebrouck and R.
Salmonella in the crop and ceca of broiler chickens Ducatelle, 2006. The use of organic acids to combat
before and after preslaughter feed withdrawal. Salmonella in poultry: a mechanistic explanation of
Poult. Sci., 78: 45-49. the efficacy. Avian Pathol., 35: 182-188.
Foley, S.L., A.M. Lynne and R. Nayak, 2008. Salmonella Vandeplas, S., R. Dubois Dauphin, Y. Beckers, P.
challenges: prevalence in swine and poultry and Thonart and A. Thewis, 2010. Salmonella in
potential pathogenicity of such isolates. J. Anim. Sci. chicken: current and developing strategies to reduce
86: E149-62. contamination at farm level. J. Food Prot., 73: 774-
Furuse, M., S.I. Yang, N. Niwa and J. Okumura, 1991. 785.
Effect of short chain fatty acids on the performance Vicente, J., S. Higgins, L. Bilke, G. Tellez, D. Donoghue,
and intestinal weight in germ-free and conventional A. Donoghue and Billy M. Hargis, 2007a. Effect of
chicks. Br. Poult. Sci., 32: 159-165. Probiotic Culture Candidates on Salmonella
Hargis, B.M., D.J. Caldwell, R.L. Brewer, D.E. Corrier, Prevalence in Commercial Turkey Houses. J. Appl.
and J.R. Deloach, 1995. Evaluation of the chicken Poult. Res., 16: 471-476.
crop as a source of Salmonella contamination for Vicente, J.L., L. Aviña, A. Torres-Rodriguez, B. Hargis
broiler carcasses. Poult. Sci., 74: 1548-1552. and G. Tellez. 2007b. Effect of a Lactobacillus spp-
Hinton, A.,Jr., R.J. Buhr and K.D. Ingram, 2000. based Probiotic Culture Product on Broiler Chicks
Reduction of Salmonella in the crop of broiler Performance under Commercial Conditions. Int. J.
chickens subjected to feed withdrawal. Poult. Sci., Poult. Sci., 6: 154-156.
79: 1566-1570. Vicente, J., A. Wolfenden, A. Torres-Rodriguez, S.
Jarquin, R.L., G.M. Nava, A.D. Wolfenden, A.M. Higgins, G. Tellez and B.M. Hargis, 2007c. Effect of
Donoghue, I. Hanning, S.E. Higgins and B.M. a Lactobacillus-based Probiotic and Dietary Lactose
Hargis, 2007. The Evaluation of Organic Acids and Prebiotic on Turkey Poult Performance With or
Probiotic Cultures to Reduce Salmonella enteriditis Without Salmonella enteritidis challenge. J. Appl.
Horizontal Transmission and Crop Infection in Poult. Res., 16: 361-364.
Broiler Chickens. Int. J. Poult. Sci., 6: 182-186. Voetsch, A.C., F.J. Angulo, T. Rabatsky-Ehr, S. Shallow,
Kim, A., Y.J. Lee, M.S. Kang, S.I. Kwag and J.K. Cho. M. Cassidy, S.M. Thomas, E. Swanson, S.M. Zansky,
2007. Dissemination and tracking of Salmonella M.A. Hawkins, T.F. Jones, P.J. Shillam, T.J. Van
spp. in integrated broiler operation. J. Vet. Sci., 8: Gilder, J.G. Wells, P.M. Griffin and Emerging
155-161. Infections Program FoodNet Working Group. 2004a.
Kubena, L.F., J.A. Byrd, C.R. Young and D.E. Corrier, Laboratory practices for stool-specimen culture for
2001. Effects of tannic acid on cecal volatile fatty bacterial pathogens, including Escherichia coli
acids and susceptibility to Salmonella typhimurium O157:H7, in the FoodNet sites, 1995-2000. Clin.
colonization in broiler chicks. Poult. Sci., 80: 1293- Infect. Dis. 38 Suppl 3:S190-7.
1298. Voetsch, A.C., T.J. Van Gilder, F.J. Angulo, M.M. Farley, S.
Lynch, M., J. Painter, R. Woodruff, C. Braden and Shallow, R. Marcus, P.R. Cieslak, V.C. Deneen, R.V.
Centers for Disease Control and Prevention. 2006. Tauxe, and Emerging Infections Program FoodNet
Surveillance for foodborne-disease outbreaks- Working Group. 2004b. FoodNet estimate of the
United States, 1998-2002. MMWR Surveill. Summ., burden of illness caused by nontyphoidal
55: 1-42. Salmonella infections in the United States. Clin.
Mikolajczyk, A. and M. Radkowski, 2002. Salmonella Infect. Dis. 38 Suppl 3: S127-34.
spp. on chicken carcasses in processing plants in Wolfenden, A.D., J.L. Vicente, J.P. Higgins, R. Andreatti,
Poland. J. Food Prot., 65: 1475-1479. S.E. Higgins, B.M. Hargis, G. Tellez, 2007. Effect of
SAS Institute Inc., 2002. SAS user’s guide: statistics. organic acids and probiotics on Salmonella
SAS Institute Inc., Cary, N.C. enteritidis infection in broiler chickens. Int. J. Poult.
Tellez, G., C.E. Dean, D.E. Corrier, J.R. Deloach, L. Sci., 6: 403-405.
Jaeger and B.M. Hargis, 1993. Effect of dietary Zar, J., 1984. Pages 348-351 In: Biostatistical Analysis.
lactose on cecal morphology, pH, organic acids, 2nd ed. Prentice-Hall. Englewood Cliffs, NJ.
and Salmonella enteritidis organ invasion in
Leghorn chicks. Poult. Sci., 72: 636-642.
