Microbial spoilage of milk and milk products

MICROBIAL SPOILAGE OF MILK AND MILK PRODUCTS
  • Spoilage occurs when microorganisms degrade the carbohydrates, proteins, fats of milk and produce noxious, end products. Milk products as follows;

Spoilage type

Organisms involved

Signs of spoilage

Souring

Lactobacillus sp.
Streptococcus sp.

Sour milk, Curd formation

Proteolysis

Pseudomonas sp.Bacillus sp. Bacillus subtilis,

B. cereus var. mycoides,

Pseudomonas putrefaciens, p. viscose, Streptococcus, liquefaciens, and proteus spp.

Bitterness

Sweet curdling

Bacillus sp.

Proteus sp.

Micrococcus sp.

Alkaline pH

Curd formation

Lipolysis

Pseudomonas sp. Pseudomonas fluorescens

Achromobacter lipolyticum;

yeasts, e.g., Candida lipolytica; and

moulds, e.g., Pencillium spp.,Geotrichum candidum.

Rancid odour

Gas production

Clostridium sp.

Coliform bacteria, Certain yeasts, e.g., Torula cremoris,

Candida pseudotropicalis, and Torulopsis sphaerica

Gassiness

Ropiness

Alcaligenes sp.,Klebsiella sp.,Enterobacter sp.

Stringy or slimy milk

Red rot

Serratia marcescens

Red coloration

Grey rot

Clotridium sp.

Gray coloration, Foul smell

Dairy mould

Aspergillus sp. Penicilium sp., Geotrichum sp.

Mouldy appearance

 

 
Last modified: Thursday, 12 April 2012, 7:12 AM