Processing of milk - Contd...

Additives

Certain additives such as calcium chloride and colouring matter are added to the cheese milk after pasteurization. Calcium chloride helps to provide appropriate balance between the soluble and colloidal calcium in milk, which leads to successful coagulation. It as been shown that a calcium concentration of 140 – 160 mg per 100 ml is ideal but larger doses can destabilize some of the casein fractions. The most popular colouring matter used in the cheese industry is the water soluble annatto, which is extracted from the fruits of Bixa orellana .

The addition of annatto per 450 litres of milk may be less than 35 ml for slightly coloured cheese, 35 - 55 ml for medium coloured cheese and 115 – 230 ml for highly coloured cheese varieties.

The annatto is normally added to the cheese milk with the starter culture or 15 minutes before the addition of coagulating agent.

Starter cultures

The starter cultures are used in the cheese industry for production of D, L or DL-lactic acid as a result of lactose fermentation, which is important during the coagulation and texturizing of the curd. Secondly, for the production of flavor compounds and in some cases, for e.g. Swiss cheese gas production. Thirdly, the enzymes such as peptide hydrolase, lipases released by the starter bacteria play an important role in the maturation of cheese. Finally the lactic acid produced by the starter bacteria contribute towards flavour and the acidic condition prevents the growth of pathogens and spoilage causing organisms.