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In this article we will discuss about the process of cheese making.
The large number of microorganisms play a role in the ripening process. On the first day of cheese making process, the microbial number in the starting material ranges from one to two billion g_1. Therefore, the production declines because of insufficient oxygen, high acidity and the presence of inhibitory compounds that are produced as the cheese ripens.
It is mainly the action of their cellular enzymes on lactose, fat and proteins that creates the ripened cheese flavour. The gas forming culture of Propionibacterium shermanii is essential for giving swiss cheese its eye, or holes and flavour. The specificity of cheese depends upon the varieties of microorganisms used.
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The process of cheese making, involves nine steps:
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(a) preparing the milk,
(b) forming a curd,
(c) cutting,
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(d) cooking,
(e) separating the whey,
(f) salting the residue,
(g) applying microbes,
(h) pressing the curd,
(i) ripening the young cheese.
Mostly, a ripened cheese is made from raw or under pasteurized milk which must be held for at least 60 days. During that time the salt, the acidity, the metabolic compounds of ripening and the absence of oxygen usually destroy food-poisoning organism.
During preparation of the milk, some colouring agents can be added which includes β-carotene and extracts of plants e.g. Bixa orellana and Capsium spp. Milk is transformed into smooth, solid curd more commonly known as chymosin which converts milk curd at 32°C in 30 min.
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Rennet can be extracted from Mucor miehei, M. pusillus and Endothica parasiticus. The rennin attacks casein and forms lattice or curd. The protein in this chymosin curd is called paracasein, because it is bound largely with calcium, it appears initially as dicalcium paracasein. In the third step, the wire knives or cutting bars are used to reduce the large bed of curd into small cubes of 1.5 cm.
This step increases the surface area. During the cooking period, small cubes contracts and expel whey. For cheddar and related cheeses the optimum temperature is 37°C while Emmentaler and Gruyere curds are cooked at about 54°C. The cooking continues for a period ranging from 1 hour to an hour and half.
Next process is salting where cheese maker applies dry salt to the curd. The immature cheese in saturated brine is immersed for about 2 to 72 hours. In the pressing stage, sometimes external pressure is applied on the wet, warm curd which is confined in wood, plastic or metal form or a cloth bag. Pressing is the end of preparatory phase of making a ripened cheese.
