ABSTRACT
Milk provides water, sugar, proteins and minerals that are suitable for the growth of microorganisms. While some microorganisms can be pathogenic for animals and humans, others render the milk unsuitable for consumption. Spoilage is defined as becoming unfit for human consumption due to changes in the food's texture, colour, odour or flavour. These changes can occur through chemical or microbiological mechanisms. Enzymatic activity leading to spoilage can include proteolysis, lipolysis and carbohydrate degradation. The sources of contamination of milk by spoilage microorganisms are essentially the farm environment, cows, milking equipment, tanker and transport chain during milk production. At the beginning of lactation, microbial numbers are low, but as milking progresses over the season, microorganisms can accumulate to the upper reaches of the teat. Understanding and preventing spoilage of cow's milk microbial load of the milk determines the time milk can be held.
