1. Feta Cheese

Standards

Maximum moisture 55%; minimum fat 22% (Table 6.1).

Milk

Traditionally made from goat or sheep milk. A protein/fat ratio up to about 0.91 will ensure a legal minimum fat content according to Canadian standards. A smoother cow milk product can be made by selecting milk with higher fat contents in the range of 5.5 to 6.0%. Whiter cheese can be produced from cow milk by homogenizing the milk.

Traditional Procedure (Structured Feta)

1. Pasteurize 72°C for 16 s or 62.5°C for 30 min.
2. Add sufficient mesophilic DVS (direct-to-the vat) culture to lower the pH to less than 4.6 within 24 h. Normally Lactococcus lactis and/or Lactococcus cremoris cultures are used. Ripen 1 hr. at 30 – 31°C or until TA increases by 0.01%.
3. While the milk is ripening: (1) add 20 mL of a solution of 30% CaCl₂ per 100 Kg of milk; and (2) if desired, add 0.1 to 0.5 g of lipase per 100 Kg milk.
4. Measure 6,000 IMCU of coagulant per 100 Kg milk. Dilute the coagulant in at least 200 mL of water per 100 Kg of milk. Ensure the milk temperature is stabilized at 30 – 31°C, then, add the diluted rennet into the vat with the agitators running. Agitate for about two minutes and then remove the agitators. Setting should occur in 30 to 40 min. However, allow the curd to set for 60 min.
5. After setting for 60 min, cut the curd into pieces of about 7 – 15 mm.
6. Agitate for 20 min. Agitation should be as gentle as possible without allowing the curd to settle or form clumps.
7. Dip curd and whey into rectangular molds on a drain table at room temperature (20°C). Optionally, you can drain off some whey before dipping to reduce the amount of whey that has to be transferred to the forms. Fill the forms in succession and then refill again to ensure sufficient curd after overnight fermentation in the forms.
8. Turn the molds 4 – 6 times within 4 – 5h. Then cover with plastic sheets and store overnight at room temperature.
9. When the pH is less than 4.7, take the cheese out of the molds, weigh to the nearest 0.1 Kg, and cut into 10 cm cubes or to fit selected containers.
10. Weight 50 g of salt per Kg of cheese. Rub the salt uniformly on all sides of the cheese. Place the cheese cubes in plastic tubs with the lids partially open to allow the cheese surfaces to dry, and store at room temperature for 24 h.
11. Add sufficient brine (8% NaCl, 0.5% CaCl₂, pH 4.6) to completely fill the containers and ensure that no head space (oxygen) will remain to support mold growth after the lid is on. Vinegar can be used to adjust the pH. CaCl₂ is best added as a food grade solution, which is readily available from dairy suppliers. An approximate formula per litre of brine is: 80 g salt + 16 g of 30% CaCl₂, + 9 ml of vinegar + tap water to make up to 1 L.
12. Ripen at 8 – 10°C for up to 30 days.
13. Store at 2 – 4°C until consumed.

Distribution

Feta cheese is packaged and distributed to retailers and restaurants in one of four ways: (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; and (4) Bulk shipments of cubes in large containers.

Process and Quality Control Notes

Yeast and mold counts are the best indicators of hygienic problems. 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.

2. Camembert cheese

Standards

56% moisture; 22% fat (Table 6.1).

Milk

Traditionally made from goat or sheep milk. A protein/fat ratio up to about 0.86 will ensure a legal minimum fat content according to Canadian standards.

Procedure

1. Pasteurize (72°C, 16 s or 62.5°C, 30 min).
2. Add sufficient mesophilic DVS (direct-to-the vat) culture to lower the pH to less than 4.6 within 24 h. Normally Lactococcus lactis and/or Lactococcus cremoris cultures are used. Ripen 1 hr. at 30 – 31°C or until TA increases 0.01%.
3. While the milk is ripening, add 20 mL of a solution of 30% CaCl₂ per 100 Kg of milk.
4. Measure 6,000 IMCU of coagulant per 100 Kg milk. Dilute the coagulant in at least 200 mL of water per 100 L of milk. Ensure the milk temperature in the vat is stabilized at 30 – 31°C; then add the diluted rennet into the vat with the agitators running. Agitate for about two minutes and then remove the agitators. Setting should occur in 30 to 40 min. However, allow the curd to set for 60 min.
5. After setting for 60 min, cut the curd into pieces of 7 – 15 mm.
6. Agitate for 20 – 40 min. Agitation should be as gentle as possible without allowing the curd to settle or form clumps.
7. Dip curd and whey into cylindrical Camembert molds on a drain table at room temperature (20°C). The preferred mold dimensions are 11.5 cm in diameter and 11.5 cm high. Molds available in the Food Science pilot plant are 8.5 cm in diameter and 10.5 cm high. Optionally, you can drain off some whey before dipping to reduce the amount of whey that has to be transferred to the forms. Fill the forms in succession and then refill again to ensure sufficient curd after overnight fermentation in the forms. Note: if some of the curd is to be used for Feta cheese. Fill the Feta forms first and then fill the Camembert forms.
8. Turn the molds 4 – 6 times within 4 – 5 h. Then cover with plastic sheets and store overnight or until the pH is 4.6 – 4.9.
9. Weigh sufficient salt to provide 3% of the weight of the cheese. Rub the salt uniformly over the surfaces of the cheeses. Place the cheese on plastic mats in plastic tubs with the lids partially open to allow some drying off of the cheese, and store at 12 – 13°C for 24 h.
10. If Camembert culture is to be sprayed on the cheese, disperse it in water and spray on all surfaces of the cheese. The cheeses can also be inoculated by dipping them in mold spores dispersed in water. Store the cheese at 95% RH and 12 – 14°C for 6 – 15 days, with daily turning, until a luxurious growth of white mold is evident. Alternatively, the cheese can be ripened on plastic mats in large plastic tubs with loose fitting lids to maintain humidity and allow some air exchange.
11. Wrap in semi-permeable paper or foil and store at 4 – 8°C. 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 molds. This is a particular concern with respect to aciduric pathogens such as E. coli 0157: H7 and Listeria monocytogenes, which may survive the initial acidic conditions and then grow when the pH increases during ripening.

To prevent accumulation of pathogens, Camembert curing rooms must be cleaned and sanitized regularly. It is no longer acceptable to cycle Camembert continuously through curing rooms.

Grading Schedule for Brie and Camembert

(after Shaw, M.B., 1981, The manufacture of soft, surface mold ripened cheese in France with particular reference to Camembert. Society of Dairy Technol. 34(4): 131).

Cheese shape and exterior appearance:

• Regular shape, thin rind, white with some red streaking due to red organisms (4 – 5 points).
• Irregular shape, malformed sides, irregular rind thickness, irregular white mold growth with spots of other molds, “toad skin effect,” (3 – 3.5 points).
• Irregular shape, slimy rind, very moist, numerous spots (less than 2.5 points).

Colour and consistency of body:

• Light creamy colour, very little or no openness in texture, supple body, smooth, not runny at consumption temperature (4 – 5 points).
• Some discolouration, some openness, slightly layered, body too firm or too runny, (3 – 3.5 points).
• Very discoloured, much openness, very firm or runny, granular, layered (less than 2.5 points).

Flavour and aroma:

• Pleasant, characteristic, rather mild with good aroma (8 – 10 points).
• Neutral, slightly acid, very slightly bitter, slightly salty, slightly ammonia odour (6 – 7.5 points).
• Over acid, bitter, very salty, metallic, pungent, strong ammonia odour, soapy taste (less than 5.5 points).

3. Blue Cheese

Introduction

The origin of mold 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 sheep milk, and the trade name is protected throughout the world. A few of many other cheese varieties that are ripened by the mold Penicillium roquefortiare are Blue (Bleu, Blue-veined), Gorgonzola (Italy), Stilton, Wensleydale and Dorset Blue (Blue Vinney) of England, Niva of Czechoslovakia, Danablu and Mycella of Denmark, Nuworld of U.S., and Ermite of Canada. P. roqueforti has been known by other names such as P. glaucum, P. gorgonzola and P. stilton.

Standards

47% moisture; 27% fat (Table 6.1). In practice, the fat content is usually higher.

Milk

Blue cheese is traditionally made from goat or sheep milk. A protein/fat ratio up to about 0.91 will ensure a legal minimum fat content according to Canadian standards. Whiter cheese for better blue-white contrast can be produced from cow milk by homogenizing the milk. Homogenization also encourages more lipolysis resulting in more flavour development during ripening.

Procedure

1. Pasteurize (72°C for 16 s or 62.5°C for 30 min).
2. Add sufficient mesophilic DVS (direct-to-the vat) culture to lower the pH to less than 4.6 within 24 h. Normally Lactococcus lactis and/or cremoris cultures are used. Ripen 1 hr. at 30 – 31°C or until TA increases by 0.01%.
3. While the milk is ripening add 20 mL of a solution of 30% CaCl₂ per 100 Kg of milk
4. Measure 6,000 IMCU of coagulant per 100 Kg milk. Dilute the coagulant in at least 200 mL of water per 100 L of milk. Ensure the milk temperature in the vat is stabilized at 30 – 31°C; then add the diluted rennet into the vat with the agitators running. Agitate for about two minutes and then remove the agitators. Setting should occur in 30 to 40 min. However, allow the curd to set for 60 min.
5. After setting for 60 min, cut the curd into pieces of about 5 – 10 mm.
6. Agitate for 20 min. Agitation should be as gentle as possible without allowing the curd to settle or form clumps. Note: if it is desired to make Feta and Camembert from the same vat, stir the curd in the whey for about 20 minutes and then remove the desired amount of curd and whey for the Feta and Camembert as directed in Step 7 of the Feta and Camembert procedures above. The remaining curd will be used for Blue as described below.
7. About 60 min after cutting push curd away from the gate and allow it to settle for 10 min. 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.
8. Weigh the curd and measure salt equal to 1% of the weight of the curd. Sprinkle blue mold inoculum (Penicillium roqueforti) over the curd according to the manufacturer’s instructions. Mix the mold spores and salt into the cheese thoroughly, and then place the curd in cylindrical molds on a drain table. Be certain that blue cheese is kept well apart from other cheeses in the make room.
9. Turn the molds 4 – 6 times within 4 – 5 h. Then cover with plastic sheets and store overnight or until the pH is 4.6 – 4.9.
10. Weigh sufficient salt to provide 30 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 – 14°C for 24 h, or place the cheese on plastic mats in large plastic tubs with the lids loosely in place to allow air exchange. Store at 12 – 13°C for 24 h.
11. If desired, the cheese can be waxed before skewering and ripening. Alternatively: (1) the cheese may be turned, brushed and washed regularly while curing to encourage development of smear on the surface; or (2) the surface flora may be allowed to grow “wild;” it can then be brushed off before packaging.
12. Put about 40 holes on both sides of each cheese with 3 mm diameter skewer. Similarly, pierce the sides of the cheese. To obtain thoroughly veined cheeses, pierce them again after 7 – 14 days of ripening.
13. Store the cheese at 95% RH and 12 – 14°C for 6 – 8 weeks. Alternatively, the cheese can be placed on plastic mats in large plastic tubs with loose fitting lids to allow some air exchange and ripened at 12 – 14°C. Turn every day for several days and then turn once a week. The pH should increase to 6.0 – 6.25 after 8 weeks.
14. Vacuum in film or wrap in foil or other papers and store at 4 – 7°C until consumed (up to 12 months).

Curing

Few lactic starter bacteria survive the first few weeks of curing due to acid and salt inhibition. Growth of roqueforti becomes evident 4 – 8 days after skewering. This mold grows well because it is more tolerant of salt and low oxygen tension than other molds. The smear that forms on the surface is due to Brevibacterium linens or Brevibacterium erythrogenes. Too much smear is undesirable.

Activities of mold 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