spoilage of fermented food products

1. AN ASSIGNMENT
ON
SPOILAGE OF FERMENTED
PRODUCTS
SUBMITTED BY
SATYAPRAKASH BARIK
O2VSC/Ph.D./17
ADVANCES IN PROCESSING OF HORTICULTURAL CROPS

2. CONTENTS
 What is fermentation??
 Spoilage
 Detection of spoilage
 Causes of spoilage
 Role of microorganisms in spoilage of fermented food products
 Mechanism of spoilage causing microorganisms
 Control of spoilage of fermented food products

3. Fermentation
Conversion of sugar into alcohol in anaerobic condition

4. What is spoilage???
Characteristics change in flavor and color is so
that its no longer acceptable for consumption.

5. Organoleptic Methods for Spoilage Detection
Odour
• Production of volatile metabolites by microorganisms that are
detectable by odour.
• Foul-smelling amines are often produced during proteolysis
.Fruity and alcoholic odours can be produced by sugar
catabolism.
Visual
• Ropy baked goods- stringy, mucilaginous appearance when the
crumb is pulled apart.
• Fermentation of high sugar products- visible bubbling of the
product from gas produced or by expansion of the hermetically
sealed packages.
• The surface growth of spoilage microorganisms- slime or
isolated colonies that are sometimes pigmented.
• Mold spoilage - fuzzy white colonies that turn various colors as
spores are produced.
DETECTION OF MICROBIOLOGICAL SPOILAGE

6. Taste
• In fruit juices, yeast spoilage produces a buttery taste caused
by diacetyl.
• A phenolic-tasting compound, guiaicol, is produced when
Alicyclobacillus grows in fruit juices.
• Sour tastes are produced in dairy, meat, and vegetable products
after extensive acid production by lactic acid bacteria.
Microbiological Methods for Spoilage Detection
• Performed during research and development of food products
in order to establish and optimize a product’s shelf life and, as
part of quality assurance programs during commercial
production, to verify that the anticipated shelf life can be
attained.
Chemical Methods for Spoilage Detection
• The detection of spoilage by acid production : pH
measurements or by titration
• Gas chromatography can be used to detect volatile, short-chain
alcohols, carbonyls, amines, aldehydes, and aromatic
compounds

7. MAJOR CAUSES OF FOOD DETERIORATION
 Growth and activities of microorganisms (bacteria, yeasts and
molds)
 Activities of food enzymes and other chemical reactions within the
food itself
 Infestation by insects (parasites and rodents)
 Inappropriate temperature for a given food
 Either the gain or loss of moisture
 Reaction with oxygen
 Exposure to light
 Physical stress or abuse
 Time

8. GROUPS OF MICROORGANISMS INVOLVED IN SPOILAGE
 Molds : Penicillium, Aspergillus, Rhizopus, Mucor, Geotrichum,
Fusarium, Alternaria, Cladosporium, Eurotium, and Byssochlamys.
 Yeast : fermentative and oxidative yeast)
 Pseudomonadaceae
 Enerobacteriaceae :Escherichia, Erwinia, Enterobacter, Citrobacter,
Serratia, and Proteus
 Lactic acid bacteria :Lactococcus, Leuconostoc, Enterococcus, and
Pediococcus
 Coryneforms :Corynebacterium (facultatively anaerobic) and
Brevibacterium (aerobic)
 Sporeforming Bacilli :Bacillus, Clostridium, and Alicyclobacillus
 Alicyclobacillus acidoterrestris

9. Microbiological Food Spoilage Mechanisms
 Sugar fermentation with acid production
 Sugar fermentation with gas production.
 Protein hydrolysis (bacteria produce proteolytic enzymes that hydrolyze proteins in foods)
 Digestion of complex carbohydrates (Amylolytic enzymes produced by molds and bacteria
digest starches to polysaccharides and simple sugars, which destroys the viscosity of products
in which starches are used as thickening agents)
 Lipolysis (pseudomonas, molds, and staphylococci, produce lipolytic enzymes that hydrolyze
lipids, producing readily oxidizable substrates that have a rancid odor.)
 Oxidation of organic acids and alcohols (molds and oxidative yeasts can grow on acidified
foods and metabolize the organic acid. Thus the pH of the food raises to levels high enough to
permit the growth of other types of spoilage organisms)
 Guaiacol production. (Alicyclobacilli can grow in some fruit or vegetable juices, metabolizing
vanillin and other precursor molecules to guaiacol, a product with an asphalt-like or phenolic
odor)
 Surface growth (by growing on the surface. It is caused simply by the accumulation of very
high numbers of microbial cells )

10. Spoilage of Wine
Wine flower
spoilage Causal
microorganism
Ester and aldehyde taints:
increased volatile acidity
Pichia,
Hanseniaspora,
Hansenula, Candida
Formation of surface films Candida, Pichia
Mousy, horsy taints Brettanomyces
Refermentation in the bottle Saccharomyces,
Zygosccharomyces
baiili
Oxidized taint form
acetaldehyde
Saccharomycodes
ludwigii, Pichia
Deacidifiction of wine Schizosccharomyces
Considine and Frankish, 2014

11. Microorganisms sensory visual problems, such
as sediment (A1 and A2) ; film formation (B);
and turbidity and viscosity (C).
Acetic acid bacteria spoilage of red wine
Bartowsky and Henschke (2008) and Cosme et al (2018)

12. Spoilage of Beer
Spoilage by anaerobic bacteria
Propionispira raffinosivorans
Spoilage by wild yeast
Juvonen, 2015
Spoilage causing micro-
organisms
Lactobacillus plantarum
Lactobacillus mali
Lactobacillus collinoides
Pediococcus cerevisiae
Leuconostoc oenos
Zymomonas mobilis

13. Spoilage of Cidar
• Pellicle
• Due to exposure of wild yeast to oxygen
• Caused by- Brettanomyces sp.

14. Spoilage of sauerkraut
Softness: insufficient salt, high temperatures during
fermentation, uneven salt distribution or air pockets
caused by improper packing.
Pink colour: growth of certain types of yeasts on the
surface of the kraut. These may grow if there is too much
salt, an uneven distribution of salt or if the kraut is
insufficiently covered during fermentation.
Rotted kraut: found at the surface, where the cabbage
has not been covered sufficiently to exclude air during
fermentation.
Darkness: by unwashed and improperly trimmed
cabbage, insufficient juice to cover the cabbage during
fermentation, uneven salt distribution, exposure to air,
high temperatures during fermentation, processing or
storage, or by a long storage period.

15. Blue or Green Garlic
• Garlic contains sulfur compounds that might react
with cooper to form copper sulfate, a blue or blue-
green compound.
• Storing garlic bulbs in dry air for 32 days at or above
70 to 80oF before use will prevent formation of
green or blue-green pigments.
Black pickles
• formation of a ferrous sulfide complex
• Due to growth of a black-pigmented bacteria,
Bacillus nigrificans..
Clouding of pickle
• Cloudy liquid might be a sign of spoilage. Due to
mold
Spoilage of Pickle

16. Spoilage of cheese
Spoilage causes symptoms Related microorganism
Mould Production of mycotoxins
Penicillium, Aspergillus,
Cladosporium, Mucor, Fusarium,
Monilia and Alternaria
Yeast Gassiness, off-flavor and
odors, slime production
Candida, Pichia, Yarrowia lipolytica,
Geotrichum
candidum, Kluyveromyces
marxianus and Debaryomyces
hansenii.
Bacteria Rancidity, liquefication, slime
formation
pseudomonads and certain
Coliforms, Clostridium botyricum

17. Due to
Caliform bacteria
Due to
Butyric acid bacteria
Due to mold

18. Spoilage by mold
Spoilage of yogurt

19. CONTROL OF MICROBIOLOGICAL SPOILAGE
Affect the type and rate of microbial spoilage.
• water activity
• pH
• preservative compounds
• O/R potential
Each of these properties, while present in the food at some “natural”
level, can be manipulated during food product formulation to better
control food quality and safety.
Intrinsic Factors to Control Microbiological Spoilage

20. Extrinsic factors to control microbiological spoilage
Temperature
• Influences enzymatic reactions as it has an important
role in promoting or preventing microbial growth.
microorganis
ms
Optimum
temperature
Growth
range
Thermophiles 55 °C 30 - 75 °C
Mesophiles 35 °C 10 - 45 °C
Psychrotrophs 20 - 30 0 - 40 °C
Psychrophiles 15 °C -5 - 20 °C
Atmosphere
• by altering the atmosphere within a food package (oxygen and
CO2) the growth of micro-organisms can be controlled.
• Vacuum packing food removes available oxygen and thereby
prevents the growth of aerobic organisms
Relative Humidity
• The relative humidity in which a food is stored can
have an influence on the water activity of that product
and an influence on the growth of microorganisms on
the surface of a product
Hurdle concept
• control microbial growth by placing small barriers against micro-organism growth
by the various intrinsic and extrinsic influences, the micro-organisms are unable
to overcome all the small ‘hurdles’ and are unable to grow

21. REFERENCE
 Considine, J.A. and Frankish, E., 2014. A Complete Guide to Quality in Small-
Scale Winemaking, first ed. Academic Press, Waltham, USA.
 Bartowsky EJ and Henschke PA. 2008.Acetic acid bcateri soilage of bottled red
wine-A review. International Journal of food microbiology. 125(11): 60-70.
 Cosme F, Vicela A, Ribeio LF, Ines A and Nunes FM. 2018. Wine microbial
spoilage:Advances in defects remediation. Microbial contamination and food
degradation.271-314
 Juvonen R. 2015.Strictly anaerobic beer spoilage bacteria. Brewing
microbiology.195-218