Microorganisms in Milk
Milk is sterile at secretion in the udder but is contaminated by bacteria even before it leaves the udder. Except in the case of mastitis, the bacteria at this point are harmless and few in number. Further infection of the milk by microorganisms can take place during milking, handling, storage, and other pre-processing activities.
Lactic acid bacteria: 
This group of bacteria is able to ferment lactose to lactic acid. They are normally present in the milk and are also used as starter cultures in the production of cultured dairy products such as yogurt. Note: many lactic acid bacteria have recently been reclassified; the older names will appear in brackets as you will still find the older names used for convenience sake in a lot of literature. Some examples in milk are:
·         Lactococci
Image result for milk
o   L. delbrueckii subsp. lactis (Streptococcus lactis )
o   Lactococcus lactis subsp. cremoris (Streptococcus cremoris )
·         Lactobacilli
o   Lactobacillus casei
o   L.delbrueckii subsp. lactis (L. lactis )
o   L. delbrueckii subsp. Bulgaricus (Lactobacillus bulgaricus)
·         Leuconostoc
Coliforms: 

Coliforms are facultative anaerobes with an optimum growth at 37° C. Coliforms are indicator organisms; they are closely associated with the presence of pathogens but not necessarily pathogenic themselves. They also can cause rapid spoilage of milk because they are able to ferment lactose with the production of acid and gas, and are able to degrade milk proteins. They are killed by HTST (high temperature short time) treatment; therefore, their presence after treatment is indicative of contamination. Escherichia coli is an example belonging to this group.

Related Posts:

  • List of Category A Infectious Substances A Category A substance (pathogen or agent) is “an infectious substance which is transported in a form that, when exposure to it occurs, is capable of causing permanent disability, or life- threatening or fatal disea… Read More
  • Limitation of Gram Staining We all know that Gram stain is the most important staining technique for identifying bacteria using light microscopy but Gram staining techniques also have some limitations. We know how to perform gram stain but we may … Read More
  • Food poisoning Bacteria & Virus 1.      Bacillus cereus Ingestion of food contaminated with Bacillus cereus or toxins produced by this organism is responsible for foodborne illness. Bacillus cereus produces enterotoxins. It… Read More
  • Disease of E coli What Is an Intestinal Infection Due to E. Coli?  E. coli is a type of bacteria that normally live in the intestines of people and animals. However, some types of E. coli, particularly E. coli 0157:H7, can cause inte… Read More
  • Serological Diagnosis of Hepatitis B virus Infection HBsAg and hepatitis B e antigen (HBeAg) are the first markers identified in the serum of patients acutely infected with HBV. Detection of Antigen: 1.       HBsAg (also called Australia a… Read More

0 Comments:

Powered by Blogger.

Visitors

198673
Print Friendly Version of this pagePrint Get a PDF version of this webpagePDF


 download University Notes apps for android

Popular Posts

Flag Counter