Question

Milk as a substrate for microorganisms how to analyse

Answer 1

Milk is virtually sterile when it is synthesized in a healthy cow's udder (mammary gland). Cows, like humans, are natural reservoirs of bacteria. Many of these bacteria are not harmful to humans, but some may be harmful to humans even though the cows are not affected and appear healthy.Milk may become contaminated with bacteria during or after milking. The mammary glands of cows (and humans) can become inflamed due to a bacterial infection calledmastitis. During a mastitis infection, very high numbers of bacteria present can be in the udder and in the milk. Some disease causing organisms (pathogens) can be shed through cow feces and may contaminate the outside of the udder and teats, the farm environment (bedding, for example) and the milking equipment. Although optimal growth conditions for bacteria are different for different organisms, milk contains important nutritional components for mammal growth, and, therefore, it is also an ideal medium for the growth of many different bacteria. Temperature plays an important role in bacterial growth. Many bacteria prefer to grow at body temperature(86-98°F, 30-37°C), but will grow at lower temperatures (such as refrigerator temperature) at slower rates.The area of dairy microbiology is large and diverse. The bacteria present in dairy products may cause disease or spoilage. Some bacteria may be specifically added to milk for fermentation to produce products like yogurt and cheese. A detaileddiscussion of fermentation bacteria is outside the scope of this web site, althoughthese organisms are discussed briefly in the section onyogurt productionandcheese production. This section of the website is dedicated to the discussion of pathogens because of their importance in human health.