Fresh Cheese

There are four principal types of acid coagulated fresh cheese: Cottage cheese (North American), Quark types such as Baker's cheese (European), Cream cheese, and heat-acid precipitated types including Paneer (India) and traditional Queso Blanco (Latin American). With some qualifications it can be said that these types are all made by acid coagulation of caseins rather than rennet coagulation. The qualifications are that small amounts of rennet are used to improve the texture of cottage cheese, and both Queso Blanco and Paneer manufacture employ the principle of heat-acid precipitation which includes whey proteins in the casein coagulum. Cottage cheese, quark and cream cheese are normally acidified by lactic fermentation while Paneer and traditional Queso Blanco are acidified by the addition of organic acids to hot milk. In modern commercial manufacture most Latin American white cheese is coagulated with rennet (with no culture addition) and consumed fresh.

Cottage Cheese - Short Set (Emmons & Tuckey, 1967)

Manufacturing procedures may differ considerably and still yield a high-quality product. They differ chiefly in temperature of setting and in amounts of starter and rennet. Procedures differ also in the size of curd, creaming rates, type of cream, the degree of "cottage cheese flavour" and added condiments. With any procedure, though, it is vital that the cheese maker follow it carefully and consistently from day to day.

The short-set procedure is widely used chiefly because it can be carried out within one working day and the time in a vat is minimal. It can be considered as labour-saving because the approximate time for cutting may be predicted fairly closely and the cheese maker does not have to wait for the proper cutting time. Steps in this process are:

  1. Add 5% of starter to pasteurized skim milk at 32C. Stir well for 10-15 min.
  2. Add rennet at the rate of 3 ml per 1,000 kg of skim milk at the time the starter is added, or 1 to 1 Omega hours later. If the A-C test is used to determine the cutting time, take the A-C test sample before adding the rennet.
  3. Determine the cutting time using pH measurements of the curd, the A-C test or titratable acidity of the whey. Optimum values for pH at cutting depend on the heat treatment and composition (total solids) of the skim milk. Generally, pH of 4.80 in the curd can be used for normal skim milk when rennet is used. Use 1.2 cm (3/8") knives.
  4. After cutting, the curd is left undisturbed for 15 to 20 min while the water in the jacket is heated in preparation for cooking.
  5. Raise the temperature of the heating water at a rate such that the temperature in the vat rises 0.5C each 5 min for the first 30 min. After this , the rate may be doubled and eventually tripled until a final cooking temperature of 54 - 57C is reached about 2 hours later. Stirring should be gentle to prevent shattering, yet frequent enough to prevent matting. If both matting and shattering occur, the rate of heating is probably too fast.
  6. The proper firmness should be reached after holding 15 to 20 minutes at 54-57C. The curd should be checked frequently during cooking to ensure that it does not become too firm. The pH or acidity at cutting is the chief factor influencing the firmness of curd at the final cooking temperature. If curd is consistently too firm at 54-57C, the cutting acidity should be raised, or the cutting pH should be lowered slightly. If curd is consistently too soft at 54-57C, the cutting acidity should be lowered, or the cutting pH should be raised slightly. Judge firmness of curd after cooling in water to 15-20C.
  7. After cooking, drain the whey until the whey first disappears below the surface of the curd mass, and then add the first wash water. If three wash waters are used, the first is at 20-25C the second at 10C and the third at 1.5-5C. If two wash waters are used, the first is at 15C and the second at 1.5-5C. The curd should remain in contact with each wash for 15 to 20 min and should be stirred frequently but carefully.
  8. Trench the curd carefully while draining the final wash water. Continue draining until the free water has completely drained (30-60 min).
  9. Add salt (1% of the weight of curd) either directly to the curd or in the cream.
  10. Add homogenized cream (18%) to give 4% fat in the creamed curd. If cream of lower fat content is used it is necessary to increase its viscosity using stabilizers to prevent excess free cream in the curd.

Expected yield: 6 x casein content or about 14 - 16%.

The A-C Test

  1. Add starter to the skim milk in the vat. Mix well.
  2. Place a sample of the well-mixed starter and skim milk in the A-C test beaker. Cover and take precautions against cooling.
  3. Add rennet to the skim milk in the vat immediately after taking the A-C test sample. Mix well.
  4. Immediately suspend the A-C test beaker in the vat so that the surface of the skim milk in the beaker is a little below that in the vat. Cover the vat.
  5. Periodically check the vat for coagulation. After it is coagulated begin to check the A-C beaker for coagulation with a spatula or thin knife with as little disturbance of the skim milk as possible.
  6. As soon as coagulation in the A-C beaker is first detected, cut the coagulating skim milk 2 or 3 times with the spatula and repeat the operation at 5 min intervals.
  7. Observe the surface of the A-C test samples for the appearance of fine lines of whey in the cuts made previously with a spatula. The A-C end-point is that time when the fine lines of whey first appear and usually occurs 1 - 20 min after coagulation is first detected.

Reference

Emmons, D.B. and Tuckey, S.L. 1967. Pfizer cheese Monographs -7. Cottage cheese and other cultured products. Pfizer & Co. New York, N.Y.

Quark

Quark (sometimes called European style cottage cheese or quarg) represents a group of soft fresh cheese of varying moisture and fat contents. The procedure described below produces a relatively firm, granular curd structure. If a smooth textured product (such as Baker's cheese) is desired, the pH at the time of breaking the curd should be 4.5 to 4.4 and no cooking is required. The soft smooth curd must then be separated in cloth bags or by a centrifuge. In Europe the majority of Quark and Cream type cheese are produced using ultra filtration to concentrate skim milk protein either before or after ripening.

Procedure

  1. Pasteurize the skim milk at 62C for 30 min.
  2. Cool the skim milk to 32C.
  3. Add a low temperature cheese starter (Streptococcus lactis or cremoris) at the rate of 5%. Let milk set for 4-6 h until a soft gel is formed. The pH should be about 4.8 and clear whey should appear when the curd is cut with a spatula. Alternatively 1% of culture may be used with a setting time of 12-18 hours.
  4. Stir gently to break up the curd and heat slowly to 52C. Initial heating rate should not exceed 0.5C in 5 min. Hold at 52C until the curd is firm (about 1.5 h from the time of breaking the curd).
  5. Drain most of the whey and replace it with 10C water to leach the acid flavour from the curd. Washing may be omitted if you prefer an acid cheese. It may be convenient to drain the curd in a cloth bag, in which case, it could be washed by soaking the whole bag in cold water for 15 min.
  6. Add cream or cream dressing to the curd according to taste. Suggestion: 4 - 8% using 18% homogenized cream.

Cream cheese

Cream cheese according to the Food and Drug Directorate is the cheese made from cream or milk to which cream has been added. It may contain not more than 0.5% stabilizer and shall not contain more than 55% moisture and not less than 30% milk fat.

The following procedure is a cold pack method. For greater shelf life and smoother texture, cream cheese or Neufchatel cheese can be blended with 50% cream, heating, homogenizing and hot-packing. Neufchatel cheese is similar to cream cheese, but has a lower fat content. Cream cheese is now frequently made by ultra filtration procedures.

Conventional Procedure 

  1. Standardize: Cream should be 11-20% fat. Cream of 11% fat is required to make a legal cheese.
  2. Pasteurize the cream (70C, 30 min).
  3. Homogenize at 1000-1500 psi (6900 - 10300 kPa) at 63C and cool to 30C.
  4. Add 30 kg (lb) starter and 1 cc rennet per 1000 kg (lb) of cream.
  5. When the acidity increases to 0.6 -.75 (pH 4.6) stir the curd thoroughly to remove lumps. Add water at 76C directly to the curd until the temperature is 51C. Curd should be smooth and creamy. Coarseness or mealiness is due to low fat or lack of acid development.
  6. Pour the hot curd and whey into draining bags. Sterilize the bags in boiling water before use.
  7. Allow the whey to drain freely for about 2 h. After the correct consistency is obtained, salt the curd with 0.75% salt.
  8. Pack the cheese in appropriate sized moulds lined with Saran, press lightly and chill to 2C. 

Yield: 2.7-3.1 kg of cheese per kg of fat.

Flavouring: Many flavouring materials may be used such as olives, nuts, mayonnaise, pickles, relish and pimento.

Ultra filtration Procedure For Cream Cheese

The following procedure was developed by Maubois of France and is described along with other UF cheese making procedures by Glover (1985).

  1. Pasteurize 11% cream.
  2. Add 1% lactic starter.
  3. Ultrafilter 3.3x based on fat content. This provides 30 kg of pre-cheese per 100 kg 11% cream. The pre-cheese will contain 36.5% fat (11 x 3.3), about 11% protein and about 48% total solids.
  4. Ripen to pH 5.6.
  5. Add .16 kg salt per 100 kg original cream.
  6. Add .16 kg locust bean gum per 100 kg original cream.
  7. Heat to 54C.
  8. Homogenize.
  9. Package.

Reference

Glover, F.A. 1985. Ultra filtration and Reverse Osmosis For the Dairy Industry. Technical Bulletin 6. National Institute for Research in Dairying, Reading, England.