PROCESSED CHEESE

INTRODUCTION

Cheese is the product made from the curd obtained from whole or skimmed milk, with or without added cream, by coagulating the casein and further treatment, of the separated curd by ripening ferments, special molds or seasoning.

Composition of Cheese

 

Processed cheese is generally prepared from natural cheese having different varieties with different moisture content.

The natural cheese manufactured all over the world are classified in the following groups as 80-55% moisture content 55-45% moisture content 45-34% moisture content, 34-13% moisture content. The mozzarella cheese is included into the 55-45% moisture group and cheddar cheese in the 45-34% moisture group.

The processed cheese prepared from these two and also other cheese has very good market potential.

 

Composition of Processed Cheese

 

MARKET SURVEY

 

Milk is one of the essential items of daily life in our country and it is more so as a majority of Indians are vegetarian and thus milk and milk products are indispensable necessity. The per capita consumption of milk was about 190 gms. per day at present as against 108 gms. during 1969-71. To achieve this goal, there is a need to make available milk and milk products to the people at reasonable price which can only be attained by setting up small scale modern dairy units in different milk producing areas to catter to the local needs. The development of this important agro-based industry will help in generating employment opportunities in the milk producing areas as well as in the consuming centers through well-knit market channels.

PROCESS OF MANUFACTURE

. The process may be divided into following steps.

Selection of milk and cream separator.

Setting of milk

Cutting or breaking of curd

Cooking curds

Draining or dipping

Curd knitting

Salting

Pressing

Conversion of natural cheese into processed cheese.

(1) Selection of milk and cream separator -- The milk is selected as desired under the heading of milk for cheese. Raw milk containing the fat is taken and pours into the cream separator. The cream present in the milk is separated out and now the skim milk is ready for cheese making.

(2) Setting of the milk -- Setting means preparing warm milk with starter and rennet extract or paste in order to form a smooth curd block in the vat. It may be either an acid iso-electric casein curd, set with starter only, or a sweeter, calcium paracassein curd, set with both starter and rennet extract.

(3) Cutting of curd -- A horizontal-wire knife is carefully inserted at the long end of the vat into the curd bottom with a swing gate motion. It is held upright and steadily pushed forward to the opposite end scrapping the floor of the vat. Then it is withdrawn, moved over one knife width, and is inserted. The knife is pushed back carefully on a slightly overlapping track. These movements are conducted on the uncut curd bed until all of it is in strips. The horizontal wire knife is not used to cut across the rat.

A vertical wire knife is then inserted and pushed forward in the same careful manner down the long path of the curd bed, withdrawn and reinserted, until all the area is cut once. Then it is removed and inserted to cut a cross the curd bed.

(4) Looking the curds -- Introduction of heat through the cut curds and whey for a specific time period, generally accompanied by agitation, constitutes cooking. For rennet curd cheese like cheddar, no water is let into the vat jacket. Steam alone in the vat jackets gives good maximum temperature control a very necessary requirement of rennet curd cheese.

(5) Draining whey or Dipping curds -- Draining of whey through a metal strainer. It requires 15 to 60 minutes.

Dipping is an alternative means of whey and curd separator.

(6) Curd knitting and transportation -- The knitting and transformation step entails a time period, usually following curd drainage, which permits the accumulating lactic acid to charge the curd chemically.

(7) Salting of Curds -- The salting step consists of spreading coarse salt over the curd surfaces manually, mechanically or by immersing the pressed cheese under brine. The salting of cheese improves of cheese improves its flavour, texture and appearance. The salting of various cheeses varies form 1 to 10 percent.

(8) Pressing -- The cheese prepared above is pressed into block sizes.

 

(9) Conversion of natural cheese into processed cheese

 

Natural cheese mild to sharp in flavor, after roper selection and cleaning by persons experienced in the art, are shredded or otherwise reduced in size, and heated at high temperatures in either steam-jacketed kettles or direct steam injector (vertical or horizontal closures or openers) stainless steel cookers. The melted cheese in the cooker initially separates into a fat and serum phase until the introduction of suitable emulsifying salts.

Heating, emulsification and unloading of the molten cheese requires only a few minutes. If the process is delayed, oiling off, body thickening, browning, and other undesirable features may result. At the proper time the blended smooth, textured, hot mass is ejected from the cooker into hoppers and packaged by high speed machines.

 

PROCEDURES

 

Selecting, Trimming and Reducing Cheese

8:00 A.M.

Select from cheese storage stocks, coded natural cheese lots of mild, medium, and sharp flavor-Lot size and number are determined by the final flavor desired in the processed cheese. In the mild flavor lots, no more than 15 percent of the cheese should be of acid or green character. Make a series of computations to arrive at the proper fat and solids-not-fat when a specific blend is to be processed, taking into account additives and water of condensation.

Let small-size cheese warm up to about 70oF (21.1oC). Strip the bandage or film off the cheese and scrape the surfaces very thinly with a sharp-edged, angled metal blade to remove the loose wax, mold, and other surface encrustations. Mechanical scraping machines may be used.

Grinding the Cheese

10:00 A.M.

For small-size cheese manufacturer, cut the wheels or blocks into quarters or fifths, and place them in separate bins. The division should be uniform for each lot. Then reduce them in a meat grinder or in a chopper. Large manufacturers grind or pulverize whole wheels and blocks without quartering, and blend the natural cheese lots cold as pre-mixes in stainless steel wagons with the necessary salt and emulsifiers.

Heating the Cheese

10:30 A.M.

Turn on the steam, usually 10-15 p.s.i. for jacketed steam kettle and higher for direct steam. Insert the blend, or the separate cheese components, into the kettles or the horizontal cookers. Heat with slow agitation, between 50-80 rpm, for block cheese.

Adding Water, Salt, and Emulsifiers

10:45 A.M.

Add enough water to attain the moisture content of the final cheese (as for example, in Cheddar cheese, of 39.9%), taking into account from previous experience either the loss from evaporation in steam-jacketed kettles, or the gain from the steam condensate of the direct steam injection, horizontal cookers. Then insert enough sodium chloride to give the cheese a total level of 2.5-3.0%. Natural Cheddar cheese already has about 1.4% salt. Optionally introduce annatto or appropriate other color up to 4 fluid oz. per 100 lb. cheese.

Some Emulsifier Blend Samples

1% sodium citrate plus 1% disodium phosphate

or

2% anhydrous disodium phosphate plus 0.3% trisodium phosphate

or

2% anhydrous disodium phosphate plus 1% sodium phosphate

(Graham salts ie polyphosphate)

Add 1.5%-3% emulsifier combination of choice to raise the pH of the finished cheese to 5.6-6.8. Emulsifier additions are preferably made before the temperature of the cheese attains 120oF (48.9oC) and may be in dry form or suspended in water.

Not the various texture changes in the cooking kettle. At the first heating stage, a clear layer of fat occurs. After the addition of emulsifying salts and when the temperature is at 135oF, (57.2oC), the butter oil layer disappears and a rough-textured homogeneous curd appears. At 158oF, or higher, the hot, emulsified curd mass assumes a velvety sheen.

Striking the Batch

11:00A.M.

At 158-176oF (71-80oC), hold the cheese for 3 min, then immediately empty the contents of the cooker into a filler. Conduct confirming moisture and a pH determination on the hot cheese.

Filling Containers

Fill the hot plastic mass immediately into metal foil-lined, or plastic film boxes of 1/2 to 5-lb. capacity, and load the containers, after proper labeling, into standard cardboard cases. Hold the cases inverted at room temperature for 4-18 hrs. Filled cases are coded with the date and lot number. Then store at 40oF (4.4oC) but do not freeze. Run further analytic tests including the melting.

 

Ricotta and Ricottone

 

Ricotta cheese made exclusively from whey is called “Ricotone;” if milk is added to the whey or if the cheese is made entirely from milk it is called Ricotta. At pH 6.3, the solids will precipitate from the liquid and float thereby forming a layer of curd on top. This is then carefully ladled off and drained to make the cheese. At lower pH values, the precipitate will begin to sink to the bottom of the vat. This fine (more fragile) curd can be removed after the whey has been drained out of the vat.

This recipe works for a mixture of 2 parts fresh whey to 1 part milk.

Take whey directly from the cheese vat at the time of dipping or draining.

Heat without agitating to 160° F before adding any milk (to destroy the rennet enzyme and prevent early coagulation of the proteins).

Continue heating to 170° F. Add 2 teaspoons of salt per one gallon of liquid (0.25% by weight) and mix in quickly.

Continue heating without agitation to 185° F.
Mix 0.1% of citric acid (100% pure solids) per weight of liquid. This is approx. 4 grams ((heaping 1/2 tsp.) per gallon of liquid. The citric acid should be dissolved in water. Add quickly to the center of the vat and stir in rapidly for 5-10 seconds. Watch for the curd to precipitate as small grains and blooms of larger curd masses. Add more citric acid solution if necessary. If too acid much is added at this time, the curds will begin to sink to the bottom and the cheese will not be sweet. The amount of citric acid used depends on the pH of the liquid. If the whey is more acidic, less may be used. If the whey is too acidic, the curd will precipitate and remain at the bottom of the vat. If the correct amount of acid is added, a clear separation of white curds and bright green whey will be seen.

 

As the curds are precipitating, use a perforated ladle to gently move them from the sides to the center of the vat. These lumps of curds will begin to stick together thereby forming a homogeneous mass, which remains floating on top of the liquid. The color of the whey will change during this time, becoming clear green. Work around the vat with the ladle until the precipitation is finished.
Let the curds rest for 10-15 min.

 

Ladle the curds gently into draining forms. Let the curds drain for 15-30 min. after ladling is completed. Move to a refrigerator or cold room. The cheese can be also being spooned out of the draining forms into plastic containers with lids and cooled in ice water. This disrupts the structure of the curd somewhat. Traditionally, a perforated metal can (similar in size to a can used to make milk shakes at soda fountains) was used for draining and the cheese was sold in the can with wax paper bound over the top. There are thin, plastic cup-style draining forms available now for this purpose.

 

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