Thursday, August 27, 2009

New Bacteria In Raw Milk

Raw milk usually cow milk, often contaminated with bacteria if on take a milk is not with a safe method. Some contamination on milk can spoil the milk and make it taste sour or even bitter and turn thick and sticky. Now scientists have discovered new species of bacteria that can grow at low temperatures, spoiling raw milk even when it is refrigerated. According to research published in the November issue of the International Journal of Systematic and Evolutionary Microbiology, the microbial population of raw milk is much more complex than previously thought.

The scientist found the bacteria is Chryseobacterium oranimense, which can grow at cold temperatures and secretes enzymes that have the potential to spoil milk. New technologies are being developed to reduce the initial bacterial counts of pasteurized milk to very low levels. Most enzymes will be denatured at the high temperatures used during pasteurisation, which means they will stop working. However, the heat-stable enzymes made by cold-tolerant bacteria will still affect the flavour quality of fluid milk and its products. Because of this, research into cold-tolerant bacteria and the spoilage enzymes they produce is vital.

Raw milk usually consume in the morning as opening drink before breakfast or together with their breakfast. Raw milk believe have natural benefit to the body if no contamination, but if contaminated with a bacteria may can cause sick, stomachache and even diarrhea. To make the bacteria die people also some time make a pasteurization process first to raw milk.

Pasteurization is by heating the milk to around 72°C for 15-20 seconds, by this method hope can reduce the bacteria number especially that can cause diseases. Some bacteria produce extracellular enzymes that are remarkably heat tolerant and can resist pasteurization. Lipase enzymes cause flavor defects and proteases can lead to bitterness and reduced yields of soft cheese.

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