Listeria monocytogenes in seafood f

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Listeria monocytogenes in seafood f

  1. 1. Listeria monocytogenes in seafood A Presentation for Specific and Emerging Topics in Food Microbiology Mansooreh Jami, Ph.D Student Institute of Food Science Department of Food Science and Technology BOKU-University of Natural Resources and Life Sciences Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 1
  2. 2. The Listeria genus Six identified species L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, L. ivanovii, and L. grayi Primary human pathogen L. monocytogenes • Gram (+), non-spore, motile, rod Aerobic and facultative anaerobic Psychotropic and halo-tolerant Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 2
  3. 3. Significance of L. monocytogenes Ubiquitous presence Widely distributed in the environment L. monocytogenes is found in relatively low number but under certain conditions facilitate higher number Soil & vegetation Fecal water Animal feed Foodborne pathogen that causes listeriosis Listeriosis is a serious infection caused by eating foods contaminated with the bacterium L.monocytogenes. Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 3
  4. 4. Symptoms This disease affects primarily pregnant women, newborn, and adults with weakened immune systems. Pregnant women Flu-like illness, fever, muscular pain, headache or asymptomatic Spontaneous abortion, stillbirth, septicemia, meningitis. Non-pregnant adults Mild gastroenteritis, septicemia, meningitis. Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 4
  5. 5. Food-borne listeriosis Foodborne illness caused by L. monocytogenes 14 serotypes of L. monocytogenes have been designated 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4a,4b, 4bX, 4c, 4d, 5, 6a, 6b Serotype 1/2a, 1/2b, and 4b account for 96% of human infections in the United States Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 5
  6. 6. Circulation of L. monocytogenes Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 6
  7. 7. Factors affecting growth and survival Temperature Growth range = -1 to 45°C Optimum = 30 to 37°C Psychrotrophic (refrigeration temperature; <5 °C) Mesophilic (room to body temperature; 18-38 °C) Temperatures < 0 moderately inactivate LM LM can survive freezing Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 7
  8. 8. Factors affecting growth and survival Acidity Typical pH range is 5.0 to 9.6 Optimum =neutral conditions ~6.0 - 7.0 Growth at pH of <4.3 has not been demonstrated LM can tolerate lower pH when kept at near refrigeration temperatures (vs. room & body temperatures) Most strains of LM are unlikely to grow in food products with pH < 5.2 Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 8
  9. 9. Factors affecting growth and survival Water activity Water activity (aw) LM grows well at aw of >0.95; can multiply at aw of 0.90 Some LM can survive at aw of <0.90 Salt concentration Growth at 10% Survival at 25.5% Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 9
  10. 10. L. monocytogenes in seafood Fresh seafood Raw fish Raw mollusc Raw crustacean Ready to eat seafood Cold smoked fish Hot smoked fish Gravad Semi processed seafood Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 10
  11. 11. Fresh seafood products Listeria as indigenous pathogens in aquatic environment The prevalence of L. monocytogenes in raw fish is quite low, ranging from 0 to 1% (Autio et al., 1999) to 10% (Jemmi & Keusch, 1994). An overall prevalence 3% of L. monocytogenes was observed in European fish (Davies et al., 2001). Swetha et al., 2012; L. monocytogenes was isolated from 8 % fish samples. Different geographical area, Different type of products The problems can arise when handling, processing or storing conditions provide favourable conditions for the growth of the pathogenic bacteria. Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 11
  12. 12. L. monocytogenes in lightly preserved seafood  15,000 samples  1988-2007 • • • Cold smoked fish: Aw (0.89 – 0.99), pH (3.1-7.2), Temperature (25-28 ºC) Hot smoked fish: Aw (0.89 – 0.99), pH (4.1 – 8.4), Temperature (70-90 ºC) Gravad: Aw (0.97-0.99), pH (6.1-6.3) Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 12
  13. 13. Seafood/lightly preserved seafood implicated in human listeriosis Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 13
  14. 14. EU criteria for L. monocytogenes  a n = number of units comprising the sample;  c = number of sample units giving values over m or between m and M bm=M Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 14
  15. 15. Conclusion The prevalence of L. monocytogenes generally increases along the food production chain, mainly due to crosscontamination in the production plants making this pathogen a major threat to the seafood industry. Attention must be paid to the design of food-processing equipment and to the effectiveness of the cleaning and disinfecting procedures in the production facilities, based on the known imperative preventive measures, such as Good Agricultural Practices (GAP) in the primary production, Good Hygiene and Manufacturing Practice (GMP) and also Hazard Analysis and Critical Control Points (HACCP). Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 15
  16. 16. Thanks for Your Attention! Specific Emerging Topics in Food Microbiology I Listeria monocytogenes in seafood I 27, May 2013-SS 16

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