Microorganisms play important roles in food as pathogens that can cause disease, as spoilage organisms that degrade food quality, and as cultured microbes used in food processing. Fruits and vegetables naturally contain saprophytic bacteria and fungi that can lead to spoilage when the protective barriers are broken during harvesting or processing. The major factors affecting microbial growth in fruits and vegetables include physical damage, pH, moisture content, and temperature. Common preservation methods include drying, freezing, acidification, and use of preservatives.

1. Microorganism In Foods

2. INTRODUCTION
Microorganism In Foods
Micro-organisms, in relation to food, can have one of
these 3 roles:
• Pathogenic micro-organisms can cause infections or
intoxications
• Saprophytic micro-organism play a role in
biodegradation and cause food spoilage
• Cultured micro-organisms like probiotic bacteria are
used in food processing.

3. Basic Food Borne Pathogens
• Listeria monocytogenes
• Salmonella poona
• Shigella spp.
• S. aureus

4. FRUITS & VEGETABLE

5. INTRODUCTION
• Fruits and vegetables are rich source of energy, body-building nutrients, vitamins and minerals.
• Protected mechanically by the pectins which constitute a protective gum between the cell sand gives
firmness.
• Spoilage in fruits and vegetable starts with the hydrolysis of the pectin. Once the pectinases have
damage the structure of the fruit / vegetable, other organisms start to contribute to the soft rot.
• Majority of the microorganisms in vegetables are saprophytes, such as lactic acid bacteria,
coryniforms, coliforms, micrococci, spore-formers, and pseudomonas, which may be from the air,
soil, and water.
• The fungus namely Aureobasidium, Fusarium, and Alternaria, are also commonly present but lower
in number as compare to bacteria.

6. BASIC TYPES OF SPOILAGE
On the basis of appearance:
• Microbial growth
• Change in food colour
Textural change
• Slime formation
• Tissue softening
Changes in taste and odour
• Development of nitrogenous compounds
• Organic acids
• Sulfides

7. FACTORS AFFECTING MICROBIAL
GROWTH
In Fruits :-
• Physical damage during harvesting
causes breaks in outer protective
layers of fruits that spoilage organisms
can exploit.
• High levels of sugar and a low pH in
fruits juices generally favours growth
of yeasts, moulds and acid-tolerant
bacteria.
In Vegetables :-
• Bacterial spoilage start with softening
of tissues as pectins are degraded and
the whole vegetable finally become
slimy mass.
• The higher moisture content of
vegetables as compared to grains
allows different fungi to proliferate,
but some species of Aspergillus attack
onions

8. PRESERVATION METHODS
Use of Acidultants
• Lactic acid
• Acetic Acid
Other Acidulants
• Scalding or blanching in hot water
• Drying fruits and vegetables
• Natural sun drying
Drying with a food dehydrator
• Oven drying
• Pasteurizing sun dried fruits
• Conditioning dried fruits
• Freezing
• Use of ozone

9. CAUSATIVE MICROBES
Saprophytic microorganisms
P. fluorescens
E. agglomerans
E. herbicola
Yeast and molds
• Basidiophora
• Peronospora
• Phytophthora
• Plasmopara
Saprophytic microorganisms
P. fluorosceces
E. agglomerans
E. herbicola
Saprophytic microorganisms
• P. fluorescens
• E. agglomerans
• E. herbicola

10. Yeast and molds

11. Fruit Juices
• Fruit juices are commonly contaminated with yeasts and moulds, often from insect
damage.
• Fallen fruit should thus be avoided where possible, for all of the risks outlined
below.
• Sugars and sugar concentrates are commonly contaminated with osmophilic
yeasts, for example Z.Rouxii.
• Growth is slow in concentrated solutions, but one cell per container of diluted
stock is enough to cause spoilage (davenport, 1996). Flavourings, water and other
chemicals are all potential sources of microbial contamination.
• Process machinery and filling lines are particularly problematic and strict hygiene
is essential.

12. Pickles
• Pickling, also known as brining or corning is the process of
preserving food by anaerobic fermentation in brine (a
solution of salt in water) to produce lactic acid, or marinating
and storing it in an acid solution, usually vinegar (acetic acid).
• The resulting food is called a pickle. This procedure gives the
food a salty or sour taste. In South Asia, edible oils are used as
the pickling medium with vinegar. Another distinguishing
characteristic is a pH less than 4.6, which is sufficient to kill
most bacteria.

13. • Pickling can preserve perishable foods for months.
Antimicrobial herbs and spices, such as mustard seed, garlic,
cinnamon or cloves, are often added.
• If the food contains sufficient moisture, a pickling brine may
be produced simply by adding dry salt.
• Natural fermentation at room temperature, by lactic acid
bacteria, produces the required acidity. Other pickles are
made by placing vegetables in vinegar.
• Unlike the canning process, pickling (which includes
fermentation) does not require thatthe food be completely
sterile before it is sealed.

14. MEAT

15. INTRODUCTION
• Raw meat in general contains bacteria,
including pathogenic and spoilage
ones.
• As warm blooded animals naturally
carry bacteria such as salmonella spp.
• Raw meat may be contaminated with
bacteria during the slaughtering
process such as evisceration and
dressing procedures.

16. Microorganism In Meat
• Raw meat may contain bacteria such as
E.coli, Salmonella & Listeria.
• Thorough cooking these harmful microbes
but meat can become contaminated again if
it is not handled and stored properly.

17. Main cause of meat spoilage
• Three factor contribute to microbial growth
Heat is the foremost concern.
Microbes grow rapidly in a carcoss, if it allowed to stay
warm.
Meat begins spoil above 40F.
The most common microorganism involved in spoilage are
Psedomonas spp, Enterobacteriaceaae family, lactic acid
bacteria

18. Prevention Of Spoilage By Microbes
• Remove expired or spoiled.
• Store it in right place in fridge.
• Prevent mold growth in the fridge.
• Prefer freezer burn.
• Set foods on the counter or in the pantry.
• Separate some foods to prevent spoilage.

19. Spoilage
Types Of Spoilage :
Microbial spoilage
Non – Microbiaol
spoilage
Condition For Spoilage
Water
pH
Physical Structure
Oxygen
Temperature

20. POULTRY

21. INTRODUCTION
• Poultry can be defined as domestic
fowls, including chickens, turkeys,
geese and ducks, raised for the
production of meat or eggs and
the word is also used for the flesh
of these birds used as food.

22. Microorganism In Poultry
• The principal spoilage bacteria found
on poultry include Pseudomonas,
Staphylococcus, Micrococcus,
Acinetobacter, and Moraxella.
• In addition, poultry often supports
the growth of certain
pathogenic(disease-causing) bacteria,
such as Salmonella.

23. Spoilage Of Poultry
• Most of microbes grow on the surface of skin
lining of body cavity and any cut surface.
• Enzymes of the fowl contributes to the
deterioration of dressed birds.
• Microbes is the chief cause of spoilage and
intestion is the primary source

24. Contamination Of Poultry Food
• Some of the microbial contaminants can grow or
survive during food processing and storage.
• Contamination of the skin and the lining of the body
cavity occurs during washing, plucking, and
evisceration.
• The process of sticking and bleeding can also introduce
contamination.

25. Use Of Preservatives
• Poultry are soaked up in organic
acids (acetic, adipic, succinic) at pH
2.5 helps lengthen shelf life
• Some fowl, like Turkey, are cured
in a solution of salt, sugar, and
sodium nitrate for several weeks at
about 3.3𝑜C

26. Spoilage of Poultry
• Most bacterial growth takes place on the surfaces
(skin, lining of the body cavity, and any cut surfaces).
• Enzymes of the fowl contributes to the deteriorationof
dressed birds.
• Bacteria is the chief cause of spoilage and the intestines
is the primary source.

27. Signs Of Spoilage
• There is an off odour.
• Change in colour.
• Feels sticky, slimy or tacky to touch.

28. FISH

29. INTRODUCTION
• Fish is one of the most perishable food
products, and therefore, quality
deterioration of fresh fish occurs rapidly
during handling and storage and limits
the shelf life of the product .
• Many pathogenic and spoilage bacteria
are able to attach on food contact surfaces,
and remain viable even after cleaning and
disinfection

30. Microbial Quality of Fish and Fish Products
• Humans and microbes have a long history together.
• The normal microbial flora consists of organisms that make their home on or in
some part of the body. In a healthy person, such organisms rarely cause disease.
• Microorganisms of the normal flora may be in symbiotic relationship, where both
microorganism and host benefit.
• The enteric bacteria that form the normal flora of the intestine assist in the
synthesis of vitamin K and some of the vitamins of the B complex.
• In commensalism, microorganisms are neither beneficial nor harmful to their host
as in the case of the large group of microbial flora that live on the skin, and the
mucous membranes of the upper respiratory tract, intestines and vagina.
• Fish is very important foodstuff in developing countries due to its high protein
content, and nutritional value.

31. Fish Spoilage
• Fish spoilage is a complex process, in which physical, chemical and
microbiological mechanisms are implicated.Many spoilage producing
bacteria (Aeromonas, Alcaligenes, Bacillus, Enterobacter, Enterococcus,
Escherichia coli, Listeria, Pseudomonas, Shewanella) and fungi
(Aspergillus, Candida, Cryptococcus, Rhodotorula) are isolated from
fresh and spoiled fish and other sea foods.
• Microbiological Spoilag Live fish is normally considered to be sterile,
but microorganisms are found in varying numbers on all the outer
surfaces (skin and gills) and in the alimentary tract of live and newly
caught fish.