Microbiology

1. MICROBIOLOGY OF
MILK PRODUCTS
KRISHNAKUMAR .C
BTM22021
1ST
YEAR
B.TECH (FT)

2. INTRODUCTION
 MILK AND MILK PRODUCTS CONSTITUTE AN IMPORTANT
ITEM OF OUR FOOD
 THESE PRODUCTS ARE VERY SUITABLE FOR MICROBIAL
GROWTH
 IT THUS ECOMES NECESSARY TO KNIW THE CHEMISTRY
OF MILK,ITS SPOILAGEMETHOD,PRESERVATION,AND
DIFFERENT DAIRY PRODUCTS WHERE MICROBES PLAY A
POSITIVE RATHAR THAN NEGATIVE ROLE

3. WHAT ARE THE DIFFERENTTYPE OF
DAIRY PRODUCTS ARE THERE?

4. DAIRY PRODUCTS

5. IMPORTANCE OF MILK PRODUCTS
 NUTRIENT RICH
 CALCIUM SOURCE
 BONE HEALTH
 PROTEIN
 GUT HEALTH
 VITAMINS AND MINERALS
 VERSATILE INGREDIENT

10. CURD [DAHI]
 CURD IS TRADITIONAL FERMENTED DAIRY
PRODUCT THAT ORIGINATED IN INDIAN
SUB – CONTINENT
 THE WORD DAHI SANSKRIT WORD MEANS
FERMENTED MILK
 CURD IS A TRADITIONAL FOOD MADE WITH
MILK AND BACTERIAL CULTURE.
 “LACTOBACILLUS” GROUP BACTERIA USE
FOR MAKING CURD.

11. CURD PRODUCTION

12. BACTERIA FOR CURD MAKING
 DOMAIN : BACTERIA
 PHYLUM : BACILLOTA
 CLASS : BACILLI
 ORDER : LACTOBACILLALES
 FAMILY : LACTOBACILLACEAE
 GENUS : LACTOBACILLUS
 SPECIES : IN INDIA TOTAL 250
TYPE SPECIES USED

13. LACTOBACILLUS
 PROBIOTIC BACTERIA
 USED ONVARIOUS FERMENTED FERMENTED PRODUCTS
INDUSTRIAL USE
 USED FOR SOUR BREAD,MILKYOUGHRT AND SAUSAGES
 LACTOBACILLI NEEDS MALTOSE,THE PRODUCE ETHYL ALCOHAL
AND CO2
 LACTOBACILLI PRODUCE LACTIC ACID AND ACETIC ACID GIVING
THE SOUR FLAVOUR
 PH 3.6-4.0 INHIBITS MICROBIAL GROWTH
 MILK IS SOURED BY STREPTOCOCCOUS LACTS,LACTOBACILLUS
LACTOSE ---- LACTIC ACID + ENERGY

14. SPOILAGE OF DAHI
 YEAST AND MOULDS ARE MOST
COMMON CONTOMINENT IN DAHI.
 THESE ORGANISMS GET ENTRY INTO
THE PRODUCT FROM ATMOSPHERE
 UTENSILS AND HUMAN HANDS
UNDER NATURAL CONDITIONS
 SPOILAGE OF DAHI THROUGH
SOURING OFYEAST AND MOULDS
DUE TO ITS ACIDIC NATURE.

15. 2.YOGURT
 YOGURT IS DIFFER FROM CURD USING ONLY
TWO SPECIFIC CULTURE OF BACTERIA
 THE BACTERIA ARE
STREPTOCOCCUS THERMOPHILUS
LACTOBACILLUS BULGARICUS
 THE BACTERIAS USED TO MAKEYOGURT ARE
KNOWN ASYOGURT CULTURES.
 COW MILK IS MOSTLY USED FOR MAKING
YOGURT
 SOME COUNTRIES REQUIREYOGURT MUST
CONTAIN A AMOUNT OF CFU OF BACTERIA

16. YOGURT PROCESSING

17. THE CHEMISTRY BEHIND INYOGURT
FERMENTATION

19.  THE BEST TEMPERATURE FOR
MAKINGYOGURT IS 36 TO 45 DEGREE
CELCIUS
 TOO HIGH TEMPERATURESTHE TWO
BACTERIAS ARE INACTIVATE
 LOWERTEMPERATURE SLOW THAT
GROWTH OFTHE TWO BACTERIA
AND PREVENT THEYOGURT BECAME
MORE ACIDIC

20. S.thermophilus
 DOMAIN : BACTERIA
 PHYLUM : BACILOTA
 CLASS : BACILLI
 ORDER : LACTOBACILLALES
 FAMILY : STREPTOCOCCACEAE
 GENUS : STREPTOCOCCUS
 SPECIES : S.thermophilus
 ITS A GRAM POSITIVE
BACTERIA,FACULATIVE ANAEROBE,NON
MOTILE

21. Spoilage of yogurt
 Moulds:
the most common mold causing yogurt
spoilage are
aspergillus,penicilium,rhizopus,fusarium, and
trichoderma
 Yeasts
candida spp,debaryomyces,kluveromyces etc..
YEAST AND MOULDS ARE PRIMARY
CONTOMINONTS INYOGURT

22. 3.CREAM
 IS A DAIRY PRODUCT COMPOSED OF
THE HIGHER FAT LAYER SKIMMED
FROM THE TOP OF MILK BEFORE
HOMOGENISATION.
 CREAM IS THE FAT RICH PORTION OF
MILK OBTAINED ON UNDISTURBED
FOR SOMETIME OR ON
CENTRIFUGING

23. FACTORS AFFECTING THE QUALITY
OFTHE CREAM
 RAW MILK QUALITY
 SEPERATION PROCESS
 HOLDING OF CREAM BEFORE
PROCESS
 STANDARIZATION
 HOMOGENISATION
 HEAT TREATMENT
 STORAGE AND DISTRIBUTION

24. SPOILAGE OF CREAM

26. 4.BUTTER
 MADE FROMTHE FAT AND PROTEIN
COMPONENTS OF CHURNED CREAM
 ITS CONTAINS 80% FAT
 ITS MADE BY CHURNING CREAMTO
SEPERATE THE FAT GLOBULES FROM
THE BUTTERMILK.
 BUTTER IS WATER IN OIL EMULSION

27.  BUTTER IS LESS SATISFACTORY FOR
GROWTH OF MICRBOES
BECAUSE
LESS LACTOSE
LESS MOISTURE 16%

28. MICROBES USAGE IN BUTTER
 DIACETYL PRODUCING SPECIES:
Lactobacillus lactis biovar diactyl lactis
Leuconostoc mesenteroides subsp.
Cremoris
The final acidity of creams may be ph 5.3
for mild ripened butters,ph 4.5 for
strongly flavoured butter.

29. Flavour defects in bacteria
 Rancid flavour – microbial,enzymatic
chemical degardation,the hydralysis of fat
in butter is mainly due to activity of
microbial lipases.
 Putrifactive taint – breakdown of proteins
Putrifactor organisms- Pseudomonas
putrifacien
Isovaleric acid will be produced responsible
for off flavour

30.  Cheese taints-cheese like flavours in butter
Due to association action of different gram
negative rod shaped bacteria
It will be occur store above 10 degree
 Other flavour taints
malty flavour - lactobacillus lactis var
maltigenes in cream
shunk flavour –pseudomonos mephitica

33. CHEESE
 IS A DAIRY PRODUCT PRODUCED IN
WIDE RANGES OF FLAVORSTEXTURES
AND FORMS BY COAGULATION OF
MILK PROTEIN CASEIN.
 IT COMPRISES PROTEINS AND FAT
FROM MILK.
 THE SOLID CURDS ARETHEN
SEPERATED FROM THE LIQUID WHEY
AND PRESSED INTO FINISHED CHEESE

34.  OVER A THOUSANDTYPES OF CHEESE
ARE THERE
 CHEESE ISVALUED FOR ITS
PORTABILITY AND LONG SHELF
LIFE,AND HIGH CONTENT OF
FAT,PROTEIN CALCIUM AND
PHOSPHOROUS.
 HARD CHEESES LIKE PARMESAN LAST
LONG LIFE THAN SOFT CHEESE

35. CHEESE PRODUCTION

36. TERMS IN CHEESE
 CURD-SOLID CLUSTERS WHEN SOLID
SEPERATES FROM LIQUID MILK
 WHEY-THE LIQUD PART
 CASEIN-THE PROTEIN FOUND IN MILK
AND CHEESE
 RENIN/CHYMOSIN-ENZYME EXTRACTED
FROM STOMACH OF CALVES
 RENNET-COMMERCIAL FORM OF RENIN
USED TO CURDLE MILK FOR CHEESE

43. MICROORGANISMS HELPS CHEESE
PRODUCTION
 PENICILIUM CAMEMBERTI
USED IN PRODUCTION OF
CAMEMBERT,COULOMMIRES CHEESES
USE
ITS FORMS HARD,WHITE CRUST,IT IS
RESPONSIBLE FOR GIVING THESE CHEESE THEIR
DISTICTIVE FLAVOURS.

44.  BLUE CHEESE –PENICILIUMM
ROQUEFORTI
 BLUE CHEESE IS MADE WITH ADDITION
OF CULTURES OF EDIBLE
MOULDS,WHICH CREATE BLUE GREEN
SPOTS ORVEINS THROUGH THE CHEESE
 IT HAS DISTINCTIVE SMELL EITHER FROM
THE MOLD ARE SPECIALY CULTIVATED
BACTERIA SUCH AS BREVIBACTERIUM
LINENS

45. PENICILIUM ROQUEFORTI
 RESPONSIBLE FOR THE GREENISH
 BLUE MOLDY ASPECT OF BLUE
CHEESE
 IT PRODUCE SEVERAL MYCOTOXINS
LIKE ROQUEFORTINE ETC

46. SWISS CHEESE
 A MILK BASED FOOD PRODUCED LARGE RANGE
OF FLAVOURS,TEXTURES AND FORMS
 LACTOBACILLUS HELVETICUS-PROUCES CO2 THA
GIVES SWISS CHEESE ITS HOLES.

47. PARMESAN
 ITALIAN HARD GRANULAR CHEESE
 “KING OF THE CHEESES”
 BUTRIC ACID AND ISOVALARIC ACID TOGETHER USED TO IMITATE THE
DOMINANT AROMAS
 LACTOBACILLUS LACTIS,BULGARICUS,STREPTOCOCCUS
THERMOPHILLUS,CREMORIS ARE USED

51. Milk powder
 Milk is highly perishable in nature,so it is
desirable to preserve it for later
consumption.
 Drying is the most important method of
preservation.
 In modern technologies it is possible to
convert the milk to powder without any loss
in nutritive value,i.e milk.
 Milk from powder has the same food value as
fresh milk.

52.  Milk powder manufacuturing is a process
carried out on a large scale.
 It involves removal of water under stringent
conditions while retaining all the desirable
natural properties of the milk.
 Ex colour flavour,soluability,nutritional value.
 The heat processing of milk reduced water
activity,subsequently destroy pathogenic and
spoilage microorganisms and inactive
enzymes.

53. Spoilage of milk powder
 High microbial load in milk and dairy
products is leads to spoilage
 Heat resistant microorganisms and
moulds are responsible of deteriotion of
milk powder.
 Salmonella contamination is a major
serious hazard in dried milk products.
 Staphylococcus aureus-its produce heat
staple toxin staphyloccoal entrotoxin.

54.  Listeria monocytogenes also present in
dried milk powders
 Bacillus cereus – common contominent in
dried milk. Its spores viable in dried milk
products more long time.
 Enterobactor spp. – sakazakii associated
wiyh dried milk powder.its survey in spray
drying by inoculated in skim milk powder.

55. IMPORTANCE OF
MICROBIOLOGY
IN MILK PRODUCTS

56. WHY MILK IS CALLED
COMPLETE FOOD

57. WHICH TEST WILL BE USED FOR
DETECTION OF MICROBES IN MILK

58.  METHYLYNE BLUE REDUCTION AND
PHOSPHATASE TEST METHODWIDELY
USED PRESENTS OF MICROBES IN
PASTEURIZED MILK.

59. THANKSYOU