Download GENERAL MICROBIAL ANALYSIS OF COW`S RAW MILK FROM

GENERAL MICROBIAL ANALYSIS OF COW'S RAW MILK FROM SOUTH-KAZAKHSTAN
COUNTRYSIDE
Sbasheva L. M.
al-Farabi Kazakh National University
[email protected]
Milk is a complex biological fluid probably containing about 100,000 different molecular species in
several states of dispersion. Major components of milk are proteins, lactose, fat, and minerals. Milk is an
excellent source of nutrients for humans, and yet in a different context these same nutrients provide a most
suitable medium for microbial growth and metabolism. Thus the raw milk contains a lot of different
microorganisms both as initial microflora and as a result of contamination. The initial microflora of milk
includes lactic acid bacteria (LAB), which are used in many industrial fermentation processes. In addition,
LAB are very useful for human health. Nearly all traditional dairy products as koumiss, kefir, yogurt,
cottage cheese are produced by the use of LAB. Most of LAB used in industry nowadays have already been
studied. However, the microflora of the raw milk of countryside is basically unknown.
The purpose of the study was to analyze the initial microflora of cow's raw milk delivered from
South-Kazakhstan and to isolate pure bacterial cultures for further biotechnological studies.
The study used following methods: isolation of bacteria on selective nutrient media, determination
of Coli-titer on Kessler's selective medium.
1:100 ml and 1:1000 ml dilutions of fresh cow's raw milk were cultivated on 6 different selective
media (Nutrient Broth, Mac Conkey Broth, Sabourad dextrose agar, Tryptone glucose yeast extract agar,
Milk agar, MRS agar) in 3 fold repetition. Colonies were counted, analyzed by morphology and the reaction
to Gram staining. Each colony was isolated in pure culture. The experiment was repeated after 14 days. In
total 23 pure cultures were isolated. Among them most colonies are related to cocci, 4 colonies are bacilli,
according to the morphology. It is believed that one culture is related to the genus Lactobacillus according
to morphological characteristics of the colony on the agar and the microscopic analysis.
Coli-titer was determined by cultivating milk in selective medium for coliforms. Mac Konkey Broth
was used instead of Kessler's medium. According to results coli-titer was equal to 3ml.
In conclusion, investigated raw milk due to its high nutritional content showed a rich microbiota. In
brief, the dominant microflora of raw milk generally include species of LAB (Lactococcus and/or
Lactobacillus) and yeasts. The received results will encourage future research, focused on creating a
polyfunctional and heterogeneous dairy based product.
Supervisor: PhD Akimbekov N. Sh.