CHEESE PRODUCTION – GENERAL PROCEDURES FOR HARD AND SEMI-HARD CHEESE

 Cheesemaking involves a number of main stages that are common to most types of cheese. There are also other modes of treatment that are specific to certain varieties. The main stages for production of hard and semi-hard cheese are illustrated schematically on the block chart in Figure 14.1.

The cheese milk is pre-treated, possibly pre-ripened after addition of a bacteria culture appropriate to the type of cheese, and mixed with rennet. The enzyme activity of the rennet causes the milk to coagulate into a solid gel known as coagulum. This is cut with special cutting tools into small cubes of the desired size – primarily to facilitate expulsion of whey.
During the rest of the curdmaking process, the bacteria grow and multiply and form lactic acid from the lactose. The curd grains are subjected to mechanical treatment with stirring tools, while at the same time the curd is heated, according to a pre-set programme. The combined effect of these three actions – growth of bacteria, mechanical treatment and heat treatment – results in syneresis, i.e. expulsion of whey from the curd grains. The finished curd is placed in cheese moulds, mostly made of plastic, which determine the shape and size of the finished cheese.
The cheese is pressed, either by its own weight or more commonly by applying pressure to the moulds. Treatment during curdmaking, pressing, brining and storage conditions determines the characteristics of the cheese.
The process flow chart in Figure 14.1 also shows salting and storage. Finally, the cheese is coated, wrapped or packed.

CHEESE MILK-

• Fat standardization
• Fat relative to SNF (Casein) = F/SNF (Casein) 
• Pasteurization
• 70-72 °C/15-20 s (not always employed)
• Cooling to renneting temperature about 30 °C
• Options
• Mechanical reduction of bacteria
• Spore and bacteria removing separators 
• Microfiltration

FROM MILK TO CHEESE-

• In the cheese vat
• Conditioning of cheese milk
• Additives:
• – Calcium chloride
• – Saltpetre, if permitted by law
• – Starter bacteria, appropriate to type of cheese
• – Rennet as coagulant
• Coagulum
• Cutting into grains (curd)
• Removing part of the whey
• Adding water to wash curd (semi-hard cheese production)
• Heating, scalding, directly or indirectly, depending on type of cheese
• Collection of curd for pre-pressing and/or final moulding/pressing, and if required
• Brine salting or for cheddar cheese
• Cheddaring followed by milling, salting, hooping, and pressing
• Formed, pressed, and salted cheese to ripening room storage for required time

MILK TREATMENT PRIOR TO CHEESEMAKING-

The suitability of milk as a raw material for cheese production depends largely on conditions at the dairy farm. Quite apart from the general demand for strict hygienic conditions, milk from sick cows or animals undergoing treatment with antibiotics must not be used for cheesemaking, or any other milk product.

Feeding animals on badly prepared silage can adversely affect the quality of several varieties of cheese.

MILK COLLECTION-

With the traditional method of milk reception, i.e. morning delivery of milk in churns to the dairy in the course of a few hours of all milk needed for the day’s production, the milk was treated almost immediately after being weighed in. The fat content was then standardized in conjunction with separation and pasteurization and, after regenerative cooling to renneting temperature, the milk was pumped to the cheesemaking tanks.

The practice of collecting milk from farms at intervals of two or three days is widespread. This means that particularly stringent requirements must be met regarding the way the milk is treated by the producers. Especially a quick cooling of the collected milk to 4 °C is essential. These requirements also extend to the tanker driver, who collects the milk at the farmhouses. He must have the authority to refuse to accept milk that is even slightly affected and/or impaired by off-flavours. Bovine mastitis is a common disease that causes the cow pain as well as drastically affecting the composition and the quality of the milk; farmers must discard such milk, or at least not send it to the dairy.