PROCESSED CHEESE

Processed cheese may be defined as a modified form of natural cheese prepared with the aid of heat, by comminuting and blending one or more lots of cheese, except certain types such as cream, cottage cheese, etc. with water, salt, colour, emulsifier into a homogeneous plastic mass, which is usually packed while hot.

As per the PFA rules (1976), processed cheese refers to a product obtained by heating cheese with permitted emulsifiers and / or stabilizers, viz. citric acid, sodium citrate, sodium salts of orthophosphoric and polyphosphoric acid, with or with out added condiments and acidifying agents, viz. lactic acid, vinegar, phosphoric acid and citric acid.

Processed cheese may contain not more than 4.0% of anhydrous permitted emulsifiers, and / or stabilizers, provide that the content of anhydrous inorganic salts in no case exceeds 3.0% of the finished product. It should not contain more than 47.0% moisture. The milk fat content should not be less than 40.0% of the dry matter. Processed cheese may contain 0.1% sorbic acid, or its sodium, potassium or calcium salts or 0.1% of nicin, either singly or in combination.

Specifications for processed cheese, foods and spreads

How to make processed cheese?

Receiving raw cheese (Natural cheese)

The manufacturers of processed cheese generally prefer to control the ripening of cheeses intended for processing in order to get the desired quality and quantity of the end product.

Analysis of raw cheese

Each and every block of cheese is sampled and analyzed for important parameters such as acidity, fat, moisture, salt etc. Records of analysis shall be maintained properly till the processed cheese is marketed.

Selection and Blending of natural cheese

Different age groups of cheeses are selected and brought together depending on the need and this process is called blending. Proper blending results in desired physical characteristics and uniformity of chemical composition in the end product. An experienced blender should possess judgment, experience, and technical skills to achieve success.

Although different blenders follow different guidelines, the generally practiced blending method involves selecting 75% of the cheese from 0-3 months age group and 25% of the cheese from 6-12 months old. Inclusion of highly sour cheese shall be limited to 5% and gassy cheese to 2% of the total cheese. Raw cheese selection requires great skill and age, acidity, pH, body, texture, and composition of the cheese blocks available are among the factors that have to be taken into account. 

Tempering and cleaning of raw cheese

It refers to bringing the cheese to proper consistency and hardness. Removal of inedible portion from the chesses before processing is referred to as cleaning. Cheese is brought from the curing room to the blending room till it attains room temperature and this usually takes 24-48h, referred to as tempering. It helps to soften cheese and aids in cleaning, cutting and grinding operations. Tempering operation is generally followed by cleaning and later it is processed. The outer layer, consisting of paraffin wax is removed followed by removal / scraping off of inedible portions of cheese.

Quartering and grinding

Cutting the cheese blocks into four pieces each is called quartering to facilitate grinding. Depending on the size, the individual blocks are further cut into smaller pieces or fed as such into the grinder which is similar to meat grinder. Heavy metal grinder is used to grind large sized cheese blocks.

Processing

It includes different operations including addition of water, colour, salt, emulsifiers followed by heating, stirring and emptying the kettle and packaging.

Addition of water, colour, emulsifiers and salt

Initially a part of shredded cheese is added to the processing kettle to which are added calculated amount of water, colour, emulsifier and salt. Later the remaining portions oof ground cheese is added to the kettle. The emulsifier helps to prevent fat separation during heating, imparts specific soft and smooth characteristics in the body and texture of the finished product and produces desirable melting and slicing properties in the processed cheese. Disodium phosphate and trisodium citrate are the two commonly used emulsifiers. Some times Rochelle salt, sodium pyrophosphate and sodium metaphosphate are also used. The amount of emulsifiers added varies from 0.5 to 3.0% by weight of cheese. It is usually added after mixing it with required quantity of water.

Heating, stirring and emptying of kettle

During early periods, the kettle used was open, upright, steam jacketed with dual agitators. But the modern kettle used nowadays is a closed type with provision for vacuum or air supply to aid in heating or emptying the kettle. The optimum temperature – time combination of processing the cheese is 65°C for 5 minutes. A higher heating temperature time combination is followed nowadays at 80°C for 10 minutes which results in better microbial destruction besides improving the shelf life of the product.

Packaging

The cheese when processed is conveyed straight to the filling machine when operated on a large scale basis. When operated on a small scale level, it is usually sent to the final package itself. Care has to be exercised while packaging the cheese to see that it is hot and well stirred and under semi fluid condition which is a pre requisite for packaging.

Cooling and storage

Slow cooling of packaged processed cheese is done to a temperature of 18-21°C and then it may be stored under refrigerated temperature (2-4°C).

Nutrients present in processed cheese

The emulsifying salts hydrates casein and peptidizes the processed cheese during production and hence the proportion of water soluble protein increases considerably. During the storage, the polyphosphates are converted into di and mono phosphates. Processed cheeses generally contain the same amount of nutrients as those present in cheese from which it is prepared. The protein content varies between 8 and 24% and the fat 9 and 31%. The mineral content does not vary significantly except for sodium and potassium which are present at higher proportions. Some losses in Vitamin B1 and B2, niacin, pantothenic acid and Vitamin B12 were noticed during the manufacture of processed cheese.

The free amino acids content and in-vitro digestibility of proteins increases during the processing of cheese and utilization of proteins is considered better than the raw or natural cheese. The polyphosphates added during the preparation will even contribute to the daily requirement of phosphorous. Since the recommended long term daily intake is of polyphosphate is 40 mg per kg of body weight, there is no danger of over dosage in consuming the processed cheeses regularly.

The additional phosphorous consumed on account of eating processed cheese is less than 1.2 g per day which is well within the permissible level. Moreover, processed cheese can be considered as health food because phosphates present in them will inhibit the formation of dental caries. The citrates used in the manufacture of processed cheese will cause no harm to the body since citric acids and its salts are normally present in many foods.