Processing of Feta cheese

Feta cheese is a protected designation of origin (PDO) soft white cheese ripened in brine and can be manufactured from ewes’ milk or a mixture of ewes’ and goats’ milk (up to 30%) raised on local grass. Feta is the most well-known cheese in Greece. It is a soft, white, brined cheese that is very nutritious and is an excellent source of calcium.

Traditionally feta was made with unpasteurized milk however industrial diaries now use pasteurized milk due to concerns over public health and export regulations. They also use commercial lactic acid cultures.

The milk is pasteurized at a minimum of 72 °C for 15 seconds or any equivalent time-temperature combination.

After pasteurization, lactic acid starter cultures and calcium chloride are added, as the milk is being held at 34-36 °C. After the milk has been refrigerated for 20 minutes enough rennet is added to coagulate the milk and coagulation takes place in about 40-45 min.

Coagulation process is essential for the development of a uniformed gel and finally Feta with firm texture. When coagulation is complete, the curd is cut into small cubes and, in order to increase cohesion, it is left to stand in the whey for about 5–10 min.

The small cubes are transferred into molds, in order to drain and shape the small pieces. The filled molds are stored at 16-18 C for 18 up to 24 hours and turned upside down every 2–3 h to ensure even drainage occurs and that all the curds are subject to equal amounts of pressure.

When the desired amount of whey has been removed, the fresh cheese is taken out of the mould and placed temporarily either in wooden barrels or metal containers, where salt is added in layers. The final concentration of salt in the mass of cheese is roughly 3%.

The next stage is to mature the salted cheese for 14 – 20 days in brine, at 16-18 °C in order to obtain humidity less than 56% and pH 4.4 – 4.6. At this temperature and RH a product of better texture and flavor is produced.

The second phase of maturation takes place when feta cheese is kept refrigerated in its brine, at 1-4 °C, for two months. Usually formed in square-shape blocks, Feta cheese has a somewhat grainy consistency (and is therefore crumbly), usually is white and has tangy and salty flavor.

Finally, when the cheese is ready to be distributed to consumers, it is cut up, shipped, and sold still in its brine, typically in a plastic container.
Processing of Feta cheese

Processing of set style yoghurt

Yoghurt is mainly of two types i.e. set yoghurt and stirred yoghurt. Set yoghurt (which includes fruit-on-the bottom) is formed in retail pots as lactic acid bacteria ferment lactose into lactic acid giving a continuous gel structure in the consumer container. Yoghurt properties can be enhanced by the addition or treatment with various additives.

In processing, set style yoghurt is incubated and cooled in the final package and is characterized by a firm jelly like texture. Set-style yoghurt is fermented in a retail container, filled after milk inoculation and is incubated in an incubation room at a suitable temperature normally40-43°C for approximately 2:30 to 4 hrs. Yoghurts are directly transferred to a cold store or blast chilled in cooling tunnels.

Fruit and flavors are added at different steps depending on the type of yoghurt. For set style yoghurt the fruit is added in the bottom of the cup and then the inoculated yoghurt is poured on top and the yoghurt is fermented in the cup.

Set-style yoghurt should have smooth consistency without cracks or holes, custard like, semi solid consistency without any surface whey.

Processing of set style yoghurt

Feta cheese traditional method processing

Feta cheese belongs to the co-called ‘white pickled’ group of cheeses. It requires simple equipment for its manufacture and it keeps well.

Traditional Feta cheese is produced mainly in the mountainous regions of Greece from mixture of sheep’s milk and cow’s and/or goat’s milk. It is a table cheese, a favored ingredient in salads and pastries.

The milk is heated to 32-34 ° C and traditional rennet extract from lamb’s /kid’s abomasa is added to give a coagulum ready for cutting after 50 min. Rennet mixed is at 120 ml/1000g milk.

Coagulation process is essential for the development of a uniformed gel and finally Feta with firm texture. The coagulum is the cut into 2 -3 cm cubes, left for 5-10 min in whey, and then transferred gradually into circular molds, placed on an inclined table, and turned occasionally. This facilitates whey drainage.

The curd is stored overnight in a room maintained at 18 ° C and 85% relative humidity. At this temperature and RH a product of better texture and flavor is produced. The curd should achieve pH of 4.7 in about 24 hours

When the curd is firm enough, it is then removed from the molds, cut into slices and rubbed or sprinkled them with granulated salt. The cheeses are left until a slimy layer has formed within 1 to 2 weeks; then the surfaces are cleaned and the cheeses placed into barrels, leaving no space between slices.

Brine of 6-8% NCL is added and the barrels are closed. The cheese slices remain in ripening rooms until their pH reaches 4.4-4.6 and then transferred to cold stores at 3-4 C. Maturations of Feta cheese actually begins before the curd making is finished and can be separated into two phases. The first one takes place simultaneously with dry salting in the ripening plants, at 18 ° C while the second one occurs during the storage of Feta in refrigeration.

Usually formed in square-shape blocks, Feta cheese has a somewhat grainy consistency (and is therefore crumbly), usually is white and has tangy and salty flavor.

Feta cheese can only be produced under strict product specifications in certain areas of Greece. Feta is registered as a Protected Designation of Origin (PDO) product.
Feta cheese traditional method processing

Processing of buttermilk

Natural buttermilk is a byproduct of butter manufacture and is categorized as sweet (non-fermented) or acidic (fermented).

Sweet buttermilk is obtained during butter manufacture from pasteurized non-fermented cream. Depending on the processing conditions, which may involve heating the cream before ripening at 90°C for 15 seconds or 105°C- 110°C with no holding, sour cream or sweet cream buttermilk may be produces.

Sweet cream buttermilk can be further fermented by mesophilic lactic acid bacteria.

The basic manufacturing steps of cultured buttermilk involved standardization of the fat and solids-not-fat contents, followed by homogenization heating (85° C for 30 min), fermentation by starter cultures, breaking the fermentate, cooling and packaging. The buttermilk also can be powdered.

Fermented buttermilk contains around 0.7% lactic acid and traces of diacetyl in addition to protein, minerals and about 80% of the non-fermented lactose.

Only a minor percentage of the buttermilk produced is consumed directly, the commercial use of buttermilk includes applications in the baking and dairy industries.
Processing of buttermilk