Short presentation on Microbiology of Milk

1. Noman Tahir Faiq
BBTF17M056

2. Microbiology of milk

3. What is microbiology of milk?
 Basically it is the study of milk and the microorganisms which are present in
the milk
 Like : bacteria, virus, protozoal parasites and fungi

4. Introduction about milk!
 Actually it’s the white liquid produced by the mammary
gland of animals
 Rich in fat and protein
 Also contain lactose, and various vitamins and minerals
 Primary source of nutrition for young mamals before they
are able to digest other type of food

5. Properties
 Milk is white emulsion or colloid of butter fat globules
 Presence of fat globules and the smaller casein micelles
provide the opacity to the milk
 Yellow-orange carotene imparts the creamy yellow colour
to a glass of milk
 It contains many other nutrient

6.  Milk contain 30-35 grams of protein per liter of which about
80% is arranged in cassien micelles
 Different carbohydrates including lactose, glucose,
galactose, and other oligosaccahrides
 Calcium, phosphate, magnesium, sodium, potassium,
citrate, and chlorine, all are included
 Vitamins A, B6 ,C, D, K, E, B12, thiamine, niacin, biotin,
riboflavin,folates and pantothenic acid are all present in the
milk

7. Types of microbes
 There are two types of microbes
 Favourable and pathogenic

8.  Favourable:
 These are those microbes which brings favourable changes
in flavour and appearance
 For example: Lactobacillus, Streptococcus
 Pathogenic:
 These are those which may cause disease
 For example:Bassilus cereus, listeria monocytogenes

9. Microorganims in milk

10. How milk is contaminated?
 Milk is sterile at the secretion in the udder but is
contaminated by bacteria even before it leaves the udder
 Further infection of the milk by microorganism can take
place during milking, handling, storage and other pre-
processing activities
 Milk sport the growth of variety of bacteria including
pathogenic one

11. Action of microbes on milk
>Streptococcus Lactis _________________ Souring
>Lactobacillus casei _________________ chees repining
>E coli _________________ Souring & gasiness
>Bacillus substallis _________________ Protecolysis
>Alkailigenes viscus _________________ Ropiness
>St. liquifiecence _________________ Bitter flavor
>B. substallis __________________ Sweet curdling
>St. paracitrovorus __________________ Attacks citric acid

12. Spoilage of milk

13.  Spoilage is a term used to describe the deterioration of
foods’ texture, colour, odour or flavour to the point where it
is unappetizing or unstable for human consumption
 Microbial spoilage of food often involves the degradation
of protein, carbohydrates, and fats by the microorganisms
or their enzymes
 Bacillus, Clostridium, Cornebacterium, Arthrobectar,
Lactobacillus, Microbacterium, Micrococcus, and
Streptococcus

14. Milk pasteurization
 It is the process used to destroy bacteria in milk
 Milk is heated to a sufficient temperature to kill pathogenic
bacteria
 It also kills many non-pathogenic organisms and thereby
extends the storage stability of milk
 Most commonly heating milk upto atleast 161.1 degrees
Fahrenhiet for 15 seconds

15. Milk sterilization
 It is aimed to killing all organisms, eliminating all growth
forms of bacteria
 Sterilized by heating at high temperature for few seconds to
kill the bacteria
 Enabling the milk to stored for long period of time at room
temperature