this presentation gives you a brief introduction about food spoilage, factors affecting spoilage, microbes involves in food spoilage. intrinsic and extrinsic factors involves in food spoilage.

1. FOOD SPOILAGE
By-
Kratika Mehta
Harsh Kumar Singh

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WHAT IS SPOILAGE?
 Spoilage is the process in which food deteriorates to the
point in which it is not edible to humans or its quality of
edibility becomes reduced OR
 Any change which renders a product unacceptable for
human consumption.
 Complex event in which a combination of microbial and
biochemical activities may interact.
 One of the major reason that led to preservation.

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FACTORS DETERMINING THE SPOILAGE
• Microbial colonization depends on
– characteristics of product
– The way processed
– The way stored
• Factors are characterized into four:
– Intrinsic parameters
– Extrinsic parameters
– Modes of preservation and processing
– Implicit parameters

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INTRINSIC PARAMETERS EXTRINSIC
PARAMETERS
 Physical, chemical and structural
properties.
 Inherent in the food itself.
 Important factors include water
activity, acidity, redox potential,
available nutrients and natural
antimicrobial substances.
 Factors in the environment
where food is stored
 Temperature, humidity
and atmosphere
conditions

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MODES OF PRESERVATION AND PROCESSING
 Physical or chemical treatment.
 Change characteristics of food product .
 Determine the micro flora associated with the
product
IMPLICIT PARAMETERS OR MICROBIAL
INTERFERENCE
 These are the result of the development of
synergistic or antagonistic microbes.
 It can be said as the destruction of one
organism by another species releasing H2 O2 ,
bacteriocin and other di-acetyl compounds.

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Synergistic Production or availability of
essential nutrients due to the growth of
certain organisms, which allow the
growth of another group which were
otherwise unable to grow.
Antagonistic : Competition for essential
nutrients, changes in pH value or
redox potential or formation of
antimicrobial substances.

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TYPES OF SPOILAGE
Two types of Spoilage:
• Microbial spoilage
• Non- Microbial
Based on rate of spoilage:
• Highly perishable – Meat, fish, poultry,
eggs, milk, most fruits and vegetables.
• Semi perishable – Potatoes, some apple
varieties, nutmeats
• Stable or non-perishable – Sugar, flour,
dry beans

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SPOILAGE OF FRUITS AND VEGETABLES
o The organism responsible for taints are acid tolerant bacteria:
– Lactobacillus spp.
o Deterioration can be caused by action of animals, birds, bruising,
wounding, cutting, freezing, desiccation or other mishandling and growth
of microorganisms; environmental conditions, contact with spoiled foods.
o Microbial spoilage maybe due to: –
- Plant pathogens acting on stems, leaves, flowers or roots ,
-Saprophytic organisms

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Types of spoilages:
 Bacterial soft rot
• Caused by Erwinia carotovora, ferment pectin's
• Pseudomonas marginalis, Bacillus and Clostridium cause water
soaked appearance, a soft, mushy consistency and bad odor.
 Anthracnose
• Caused by Collectotrichum lindemuthianum.
• Spotting of leaves and fruits
 Black mold rot
• Caused by Aspergillus niger
• Dark brown to black masses of spores of the mold termed as
smut

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 Rhizopus soft rot
• Caused by species of Rhizopus
• Soft and mushy rot
• Cottony growth of mold forms black spots of sporangia covering the
foods.
 Alternaria rot
• Caused by Alternaria tenuis
• Greenish-brown to brown black spots
Fungal spoilage results in water soaked mushy areas, brown or
cream colored areas. Rots of juicy fruits result in leakage.

11. SOME MICRO-ORGANISMS INVOLVED IN THE SPOILAGE OF FRESH
VEGETABLES
Micro-organism
Bacteria
Corynebacterium sepedonicum
Ralstonia solanacearum
Pectobacterium carotovorum
var.atrosepticum
Streptomonas campestris
Xanthomonas campestris
Fungi
Botrytis cinerea
Botrytis allii
Mycocentrospora acerina
Trichothecium roseum
Fusarium coerulrum
Aspergillus alliaceus
vegetable
Potato
Potato
Potato
Potato
Brassicas
Many
Onions
Carrots
Tomato cucurbits
Potato
Onion garlic
symptom
Ring rot of tubers
Soft rot
Soft rot
Scab
Black rot
Grey mold
Neck rot
Liquor ice rot
Pink rot
Dry
Black rot
11

12. SPOILAGE OF FRUIT AND VEGETABLE JUICES
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 The fermentation of organic acids of the juice by lactic acid bacteria.
E.x. Lactobacillus pstorianus, malic acid to lactic acid and succinic
acid,quinic acid to dehydroshikimic acid, and citric acid to lactic and
acetic acids.
 Slime production by Leuconostoc mesenteroides, Lactobacillus brevis,
and lactobacillus plantarum in apple juice and by L.plactarum and
Streptocooci in grape juice.
 Vegetable juices contain sugars but less acid than fruit juices and have
pH around 5.0 to 5.8..
 Concentrates of fruit and vegetable juices contain high sugar
content.It favors the growth of yeast like acid and sugar tolerant like
Leuconostoc and Lactobacillus species.

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SPOILAGE OF CEREALS
• Moisture content above 12 to 13 percent may cause spoilage of
cereals
• Little moisture cause mold growth and high moisture may cause
growth of yeasts and bacteria.
• Microbial content, physical damage and temperature are also
some factors.
• Aspergillus, Penicillium, Mucor, Rhizopus, Fusarium are some
common molds; produce mycotoxins.
• Acetobacter spp, lactics and Coliforms, Micrococci and Bacillus
are some species causing spoilage.

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 Cause flour dough to develop an odor of acetic acid and esters.
 Ropiness of bread is common in home baked bread
– Caused by Bacillus subtilis, B. licheniformis and other species.
– Due to the capsulation of Bacillus ropiness occurs.
– First odour is evident, then discolouration and finally softening of the crumb with
stickiness and stringiness.
 Red bread is caused by the pigmented growth of Serratia marcescens. Molds such as
Neurospora sitophila and Geotrichum aurantiacum can also cause red colouration.

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o Chalky bread: it is due to yeast like fungi Endomycopis fibuligera and
Trichosporon variable.
o Pasta,macroni and tapioca:
 Swelling of moist macaroni is caused by gas production by bacteria resembling
Enterobacter clocae.
 Purple streaks are produced by Manilia.
 Tapioca is spoiled by orange pigmented starch hydrolyzing bacterium.
o Breakfast cereals and other cereal snacks: in the initial steps of manufacturing
of these products there are high levels of moisture and therefore the possibility
of microbial growth. Finished products contain low number of micro organism.
o Prepared dough: these products contain a yeast or a lactic acid bacteria
inoculum. Microbial contamination depends on quality of ingredients used and
sanitary practices employed.

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o Molds:
 Bread mold- Rizopus stolonifer or Rhizopus nigricans bread mold
contains white cottony mycelium and black dots of sporangia.
 Green spores are produced by Penicillium expansum Penicillium
stoloniferum,Aspergillus niger.
 Monilia sitophila produces pink conidia give a pink or reddish
color to its growth.
 Species of mucor or Geotrichumalso contaminate the bread and
produces spores.
o Cake and Bakery products:molds cause chief spoilage. Topping
fillings are more prone to microbial spoilage than actual baked
portion. Frostings due to high sugar content spoiled by molds or
yeast upon storage

17. THANK YOU