Most abundant facultative anaerobe in colon and feces
Lactose fermenter (This property distinguishes it from Salmonella and Shigella-two most common intestinal pathogen)
Antigenic properties: There are more than 1000 antigenic types of Escherichia coli.
a. O-Cell wall antigens (>150 types)
b. H- Flagellar antigen (>50 types)
c. K- capsular antigen (>90 types)
Features of E.coli which helps for Laboratory diagnosis
E.coli, ferments lactose and produces pink colonies in MacConkey Agar. (E.coli O157:H7) does not ferment sorbitol, which serves as an important criterion that distinguishes it from other strains of E.coli
On EMB agar, E coli produces characteristics green sheen
Physiological Grouping of Bacteria
Physiological Grouping
Acid producers
The organisms capable of fermenting lactose to form
lactic acid are known as acid producers. Lactic acid coagulates milk by
producing precipitation of Casein at 4.6 pH.
Hom…Read More
Classification of Dairy Bacteria
MORPHOLOGY AND CLASSIFICATION OF DAIRY BACTERIA
Introduction
Micro-organisms found in milk can be studied as groups
possessing one or more major characteristics in common. These may be divided on
the basis of their action…Read More
Pathogenic Microorganisms
in Milk
Hygienic milk production practices,
proper handling and storage of milk, and mandatory pasteurization has decreased
the threat of milkborne diseases such as tuberculosis, brucellosis, an…Read More
Spoilage Microorganisms in Milk
Spoilage Microorganisms
in Milk
The microbial quality of raw milk is
crucial for the production of quality dairy foods. Spoilage is a term used to
describe the deterioration of a foods' texture, colour, odour or flavour to…Read More
Microorganisms in Milk
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. F…Read More
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