this presentation includes a brief description about milk microorganism and general components of milk , sources of microorganism in milk , types of microorganism in milk ,significance of milk microorganism and also nutrients present as percentage in different animals like cow , buffalo and goat their milk constituents , how these all constituents affects the quality of milk

1. Session- 2020-2022
Sources and types of microorganism in Milk
PRESENTED TO,
SOS IN MICROBIOLOGY
JIWAJI UNIVERSITY GWALIOR
PRESENTED BY,
BHAVNA JHA
M.Sc 4th SEMESTER
(FOOD MICROBIOLOGY)

2. Contents
➢ Introduction
➢ General composition of Milk
➢ Sources of Microorganisms in Milk
➢ Types of Microorganisms in Milk
➢ Significance of Microorganisms in Milk
➢ Reference

3. INTRODUCTION
▪ Milk may be defined as the whole fresh , clean lacteal secretion obtained by the
complete milking of one or more healthy Milch animals, excluding obtained within
15 days before and 3 days after calving .
▪ It is an emulsion of Fat and Protein in water along with dissolved sugar minerals
,and Vitamins .
▪ Milk means the natural mammary secretion derived from complete
milking of healthy Milch animal.
▪ Without either addition there to or extraction there from , unless otherwise
provided in FSSAI regulations and it shall be free from Colostrum.
▪ Milk is a complex chemical substance in which Fat is present as emulsion
protein .

4. General composition of Milk
▪ Milk mainly contains water, lactose , butterfat , casein, Albumin and
minerals.
Water Lactose Butterfat Casein Albumin minerals
87.5% 5.0% 3.8% 3.2% 0.7% 0.7%
▪ Milk also contains Peptones , Amino acids, Nitrogen bases, Fatty acids , Sugar,
phosphates, Proteases, Enzymes and other Sugars.
▪ It contains Vitamins such as vitamin A,B,C and D.
▪ Fresh Milk contains Lactoperoxidase and Agglutinations but these
components becomes ineffective with time.

5. Animal % of
Water
% of Fat % of Milk
Protein
% of
lactose
% of
Minerals
Cow 87.25 3.80 3.50 4.80 0.65
Buffalo 76.89 12.46 6.03 3.74 0.89
Goat 87.88 3.86 3.21 4.54 0.55
▪ Milk contains nutrients, it is a best source of Calcium and it contains sodium, Magnesium,
Potassium, Zinc, Carotene , vitamins and essential Amino acids.
▪ Milk is complete food, with PH 7.0 that is an aqueous solution of Protiens, fats and
carbohydrates with many minerals and vitamins .

6. ▪ Milk constitutes an excellent medium for the growth of Microorganisms.
Sources of Microorganisms in Milk
▪ Sources of Microorganisms in Milk are :
➢ the udder of Cow
➢ Skin of the Cow
➢ Utensils and equipment
➢ Feeds
➢ Air of the Cow shed
➢ Milking Person
➢ water
➢ The udder of the cow : The Milk producing animals should be kept neat and clean.
More care should be taken keep the flanks , udder and tests clean. The interior of the
teats of the udder is warm and contains the last remains of the Milk which has microbes
which would have entered through opening of treat and multiplied.

7. ➢ Skin of the Cow: soil , faeces and dirt adhere to the skin andhairs of the cow.
Hair, dirt and dust fall into milking utensils or into the teat cups of milking machines .
➢ Utensils and equipments : Milking Utensils and equipments are major sources of
contamination of Milk . They have to be washed properly with detergent .
➢ Feeds : Dry feeds have more amount of Bacteria and less amount of fungi . These
organisms contaminate the Milk.
➢ Air of the cow shed : During the Mixing of feeds and during the cleaning process of
the floor , the air of the cow shed is highly contaminated and passed on to the milk.
➢ Milking person : Pathogenic microorganisms may enter through Milking person into
Milk. They should wear clean clothes and properly wash their hand before milking .
➢ Water : Pure water should be used for cleaning purpose. Water should be free from
Coliform organisms . Chlorination of water prevents such contaminations.

8. Types of Microorganisms present in Milk:
▪ Bacteria : Lactobaccilus is a species of lactic acid bacteria , the most common LAB
genera in Milk Lactococcus , Lactobacillus , Leuconostoc ,Streptococcus ,
Enterococcus , Psychrotrophic populations frequently include Pseudomonas and
Acinetobacter spp.
▪ The germs include Brucella , Campylobacter, Cryptosporidium , E.coli , Listeria and
Salmonella.
Microorganism present in milk are -
❑ Bacteria
❑ Molds
❑ Yeast
▪ Lactobaccilus casie and rhamnosus abundant in raw milk .

9. Bacterial types commonly associated with Milk

10. Coliforms :
▪ They are facultative anaerobes , an optimum growth at 37 C.
▪ They can cause rapid spoilage because they are able to ferment lactose with the
production of acid and gas , and able to degrade milk proteins .
▪ eg. Escherichia coli
Yeast :
▪ They are eukaryotic , single- celled microorganisms classified as members of
the fungus kingdom.
▪ Kluyvermnyce marxianus and Debaromyces hansenii and their asporogenous
counterparts , candida famata , candid kefyr and other candida spp.

11. Mold :
▪ They are present in air , water and soil and are regularly found on production
equipment and in dairy products.
▪ spoilage by Mold occur for many cheese types , but yogurt , sour cream
, butter , sweetened condensed milk, and other dairy products are also
ocasionally affected.
▪ most common mold on cheese and fermented dairy products are
Penicillium species .
▪ Mycotoxins are penicillic acid , potulin , orchratoxin A and citrinin .
▪ Mold genera frequently associated with dairy product spoilage include
Penicillium, Aspergillus, and Mucor. These molds are introduced into dairy
products through a number of environmental cross-contamination
pathways or, less commonly, by the introduction of contaminated
ingredients.

12. ▪ Mold and yeast are usually eliminated during pasteurization process and
they cause milk spoilage after the heat treatment .
Significance of Microorganisms in Milk :
▪ Microbes ferment the carbohydrates present in milk , which is mainly lactose to lactic
acid and some other products.
▪ The acid precipitates the protein in the milk ; therefore fermented products are
usually of thicker consistency then milk .
▪ Preservation of Milk born illness.

13. Reference:
➢ Frazier C William , Westhoff C Dennis, Food Microbiology , 2014,
5th edition , page no. 263-264
➢ Robinson K. Richard , Dairy Microbiology Handbook : The
Microbiology of Milk and Milk Products , 2007, 3rd edition , page no.
115,119
➢ https://www.slideshare. net > Bhattacharjee Saugat > Dairy
Microbiology > 2013
➢ https://www.slideshare.net >Mittal V. > Microbiology of
Milk>2016