Soft - ripened cheese

Feta Cheese

Standards: Moisture 55%; Fat 22%

Traditional Procedure (Structured Feta)

  1. Standardize milk to P/F = 0.90 and pasteurize (72C, 16 S or 62C, 30 min.). The Greeks prefer a perfectly white smooth product made from sheep's milk. Goat's milk also produces a white cheese. If desired, a smoother cows' milk product can be made by selecting milk with higher fat contents in the range of 5.5 to 6.0%. The undesirable cream colour of cows' milk can be removed by treating the milk with 0.03 - 0.04% titanium dioxide. Titanium dioxide is diluted with 10x its weight of warm water and added to the milk before renneting. Whiter cheese can also be produced from cows' milk by homogenizing the milk.
  2. Adjust temperature to 30C. Add 3% of S. lactis and/or S. cremoris starter. and 3 g lipase per 1,000 kg milk. Ripen for about an hour until TA increases by at least 0.05% and pH is 6.6 - 6.5.
  3. Measure 120 ml rennet per 1,000 kg milk. Dilute the rennet with 10 volumes of water and add the mixture to the milk. Agitate for 3 minutes and then allow milk to set. Setting time should be 45 - 60 min.
  4. Cut the curd using Omega" (12.8 mm knives) knives.
  5. Stir gently for 20 min.
  6. Dip curd and whey into rectangular forms on a drain table.
  7. Drain for two hours at 30C, then place the curd in a room at 18C and 85% RH. In the absence of such a room, cover the cheese with a clean cloth and store overnight at room temperature and humidity.
  8. When the pH is 4.7, 20 - 24 hrs. after adding culture, take the cheese out of the hoops, weigh to the nearest 0.1 kg, and cut into 10 cm. cubes.
  9. The required salt is 50 g of salt per kg of cheese. Weigh all the salt for all the cheese at once and distribute it uniformly by rubbing salt on all sides of the cheese surfaces. Place the cheese in 1 l plastic tubs with the lids partially open to allow some drying off of the cheese, and store at room temperature for 24 h. An alternative process, is to dry off for 1 day under a damp cloth and then store in barrels or canisters for up to 30 days at 8 to 10C. After this ripening period, the cheese may be consumed as is or stored in 8% brine.
  10. Add sufficient 8% brine to cover the cheese, and ripen at 8-10C for up to 30 days. Subsequently store at 2-4C until consumed. The brine solution should contain 0.06% calcium chloride and sufficient acetic acid (vinegar) to adjust the pH to 4.6.

Distribution

Typically, Feta cheese is packaged and distributed to retailers and restaurants in one of four forms: (1) Cubes and brine in small tubs; (2) Crumbled product in a gas flushed package (nitrogen) ready for addition to salads; (3) Vacuum packed blocks; (4) Bulk shipments of cubes in large containers.

Process and Quality Control Notes

  • At least 0.05 increase in TA before renneting
  • pH 4.7 before surface salting
  • Yeast and mould counts are the best indicators of hygienic problems. The low pH keeps bacterial spoilage to a minimum.
  • A comfortable best before date is 6 months after manufacture. Good manufacturing practice and storage can achieve 12 months shelf life.

UF Procedure (Cast Feta)

  1. Standardize milk to P/F = 0.80.
  2. Ultrafilter until retentate is 40% solids.
  3. Add 3% S. lactis culture and 250 ml rennet/1,000 kg of precheese.
  4. Quickly pour into 1 l plastic containers (3/4 full). Cover and allow to ripen to pH 4.8 (18 - 24 hrs.).
  5. Add salt (3% of weight of cheese) to surface.
  6. Store at 18C for at least 1 week before consumption.

Camembert Cheese

Standards: 56% moisture; 22% fat

Procedure:

  1. Standardize milk to 0.86 P/F and pasteurize.
  2. Add 3% S. lactis and/or S. cremoris starter and spores of P. camemberti or P. candidum. according to the manufacturer's directions. Alternatively, mould spores may be sprayed on to the salted cheese after draining. Ripen 1 hr. at 32oC or until TA increases by 0.05%.
  3. Measure 250 ml rennet per 1,000 kg milk . Dilute rennet with 10 volumes of water before adding it to the milk. Agitate for 5 min. Setting will occur in about 15 min. but do not cut until 45 min. after renneting. The pH should be 6.2 - 6.3.
  4. Cut curd using Omega" (12.8 mm knives) knives. Allow the curd to settle for 1 hr.
  5. Drain the whey down to the level of the curd. Dip the curd and remaining whey into cylindrical Camembert moulds. The preferred mould dimensions are 11.5 cm in diameter and 11.5 cm high. Moulds available in the Food Science pilot plant are 8.5 cm in diameter and 10.5 cm high. Fill the moulds quickly to 1 - 2 cm from the top. Do not refill.
  6. Turn the hoops 4 to 6 times within 4 to 5 h. hrs. and then occasionally until pH is 4.6-4.9 (8 - 12 h after adding culture).
  7. Weigh sufficient salt to provide 8 g of salt per cheese. Dry salt the cheese (6 - 9 g salt/cheese) by rubbing the salt on all surfaces. Store the cheese at 85% RH and 12 - 14C for 24 h, or place the cheese on plastic mats in large plastic tubs with the lids partially open to allow some drying off of the cheese, and store at 12 - 13C for 24 h. 
  8. If culture is to be sprayed on the cheese, disperse culture in water and spray on all surfaces of the cheese. Store the cheese at 95% RH and 12 - 14C for 6-12 days, with daily turning, until a luxurious growth of white mould is evident. Alternatively, the cheese can be ripened on plastic mats in large plastic tubs with the lids slightly open to some oxygen entry for mould growth.
  9. Pack in waxed paper or foil and store at 4-8C. Camembert cheese is fully ripe when the entire cheese is soft and creamy. The pH will increase to near 7.0 or above, especially on the surface.

Process and Quality Control Notes

  • Camembert has some special safety concerns because the acidity decreases (pH increases) dramatically due to the proteolytic action of enzymes produced by the white moulds. This is a particular concern with respect to aciduric pathogens such as E. coli 0157: H7 and Listeria monocytogenes which survive the initial acidic conditions and then grow when the pH increases during ripening. Raw milk Camembert is, therefore, of particular concern relative to hard ripened cheeses.
  • To prevent accumulation of pathogens, Camembert curing rooms must be cleaned and sanitized regularly. It is no longer acceptable to cycle Camembert continuously through the same curing rooms.

Grading Schedule for Brie and Camembert (after Shaw, M.B., 1981, The manufacture of soft, surface mould ripened cheese in France with particular reference to Camembert. J. Society of Dairy Technol. 34(4):131).

  1. Cheese shape and exterior appearance
    1. Regular shape, thin rind, white with some red streaking due to red organisms (4 to 5 points).
    2. Irregular shape, malformed sides, irregular rind thickness, irregular white mould growth with spots of other moulds, 'toad skin effect', (3-3.5 points).
    3. Irregular shape, slimy rind, very moist, numerous spots (less than 2.5 points).
  2. Colour and consistency of body.
    1. Light creamy colour, very little or no openness in texture, supple body, smooth, not runny at consumption temperature (4 to 5 points).
    2. Some discolouration, some openness, slightly layered, body too firm or too runny, (3-3.5 points).
    3. Very discoloured, much openness, very firm or runny, granular, layered (less than 2.5 points.
  3. Flavour and aroma
    1. Pleasant, characteristic, rather mild with good aroma (8 to 10 points).
    2. Neutral, slightly acid, very slightly bitter, slightly salty, slightly ammoniacal (6 - 7.5 points).
    3. Over acid, bitter, very salty, metallic, pungent, very ammoniacal, soapy taste (less than 5.5 points).

Blue Cheese

Introduction

The origin of mould ripened cheese is lost in antiquity. It was made in France at least as early as the Roman era. The name" Roquefort" first appeared in the year 1070. Roquefort cheese is made from ewes' milk, and the trade name is protected throughout the world. Other cheese varieties that are ripened by the mould Penicillium roqueforti include Blue (Bleu, Blue-veined), Gorgonzola (Italy), Stilton, Wensleydale and Dorset Blue (Blue Vinney) of England, Niva of Czechoslovakia, Danablu and Mycella of Denmark, Nuworld, U.S. and Errmite, Canada. P. roqueforti has been known by other names such as P. glaucum, P. gorgonzola and P. stilton. A white mutant of P. roqueforti was developed by Knight of Wisconsin and the resulting cheese is called Nuworld.

Standards: 47% moisture; 27% fat. In practice, the fat content is usually higher.

Procedure

  1. Pasteurize milk. P/F ratio of about 0.87 is desirable. Milk may also be homogenized before pasteurization to promote lipolysis in the cheese. If the milk is not homogenized, add 30 g lipase per 1,000 kg of milk. If the milk is highly coloured, 0.03 - 0.04% titanium dioxide diluted with 10x its weight of warm water may be added to the milk before renneting, to prevent green cheese.
  2. Add 3% mesophilic lactic starter and ripen for about an hour at 32C until TA increases by at least 0.05% and pH is 6.6 - 6.5
  3. Measure 200 ml rennet per 1,000 kg milk (dilute rennet about 20 times with water and add to the milk). Setting will occur in 20 - 30 min. but do not cut until 1 hr. after renneting.
  4. Cut curd with Omega" (12.8 mm knives). Allow curd to settle for 10 min. then agitate gently to prevent matting. When the acidity is 0.02% above cutting acid (about 80 min. after cutting) push curd away from the gate and allow it to settle for 10 min.
    [Feta cheese can be made from the same vat as Blue cheese, by dipping some of the curd and whey into rectangular forms when the acidity is about .01% above cutting acid (20-40 min after cutting), and then proceeding from Step 7 in the Feta procedure above. Similarly, Camembert cheese can be made by removing some curd and whey at 45 - 60 minutes after cutting
    and proceeding from Step 5 in the Camembert procedure above.]
  5. Remove whey to the level of the curd. Break up curd and remove remaining whey. Ditch curd and turn over after 10 min. After an additional 10 min. break up the curd to prepare for salting.
  6. Add salt, 1% of weight of curd. Sprinkle blue mould powder (Penicillium roqueforti over all the curd. It should look like well peppered scrambled eggs. Mix the mold powder thoroughly, and then place curd in cylindrical hoops on a drain table. Be certain that blue cheese is kept well apart from other cheeses in the make room.
  7. Turn cheese 5 - 10 min. after filling and then at 30 min. intervals for 2 Omega hrs. Cover with broad cloth and incubate overnight at room temperature for 16 - 20 h or until cheese pH is 4.5 - 4.7.
  8. Weigh sufficient salt to provide 50 g of salt per kg of cheese. Salt the cheese by rubbing the salt on all surfaces. Store the cheese at 85% RH and 12 - 14C for 24 h, or place the cheese on plastic mats in large plastic tubs with the lids partially open to allow some drying off of the cheese, and store at 12 - 13C for 24 h.
  9. If desired, the cheese can be treated with paraffin (waxed) before skewering and ripening. Alternatively, the cheese may be turned and brushed regularly while curing (Step 11) to encourage development of smear on the surface.
  10. Put about 60 holes on both sides of each cheese with a 3 mm diameter skewer.
  11. Store the cheese at 95% RH and 12 - 14C for 6 - 8 weeks. Alternatively, the cheese can be placed on plastic mats in large plastic tubs with the lids slightly open to allow some oxygen entry for mould growth, and ripened at 12 - 14C. Turn every day for several days and then turn once a week. The pH should increase to 6.0 - 6.25 after 8 weeks.
  12. Vacuum pack and store at 7C until consumed (up to 3 months).

Curing

Few lactic starter bacteria survive the first few weeks of curing due to acid and salt inhibition. P. roqueforti becomes evident 8 - 10 days after pricking. This mould grows well because it is more tolerant of salt and low oxygen than other moulds. The smear which forms on the surface is due to B. linens or B. erythrogenes. Too much smear is undesirable.

Activities of mould lipases and added lipases produce butyric, caproic, caprylic, capric and higher fatty acids. A predominant flavour compound is methyl-n-amyl Ketone (heptanone 2).

Caprylic acid CH3(CH2)6.COOH

Methyl-n-amyl Ketone CH3(CH2)4.COCH3