STORAGE OF CHEESE

Cheese - Storage

The quality of any cheese variety is dependent on many factors such as the quality of the milk, the activity of starter cultures and the manufacturing stages. But the criterion such as handling of cheese in the storage room and conditions provided during the maturation period are important. The latter aspects can have a bearing on the biochemical changes that take place in the curd during the storage period. This will ultimately have an effect on the final quality of the cheese. The handling ad storage conditions may vary depending on the variety of cheese and below are given some examples.

Swiss cheese

The Emmental and Gruyere type cheese undergo a secondary fermentation during the early stages of storage and the “eye” formation take place in cheese due to the metabolic activity of the propionic acid bacteria. Thus the wheel shaped Swiss cheese are matured under controlled temperature and relative humidity conditions and the following parameters amply illustrates this.

Gruyere cheese

The cheese is stored under 10°C for 3 weeks and then at 15 – 20°C for 2 – 3 months in an atmosphere of 90 – 95% relative humidity. The storage is completed at 12 – 15°C and 85% RH for 8-12 months. The cheese is turned regularly and rubbed with a damp cloth to aid the growth of those bacteria that provide the red brown smear coat.

Pressing, packaging and storing of cheese

PRESSING

The very hard, hard and semi hard varieties of cheeses are pressed in either vertical or horizontal presses under normal atmospheric condition or under vacuum. The pressing parameters, i.e. application of right amount of pressure for a specific duration of time, gives the cheese its final shape, produces a cheese with a firm and smooth surface and helps to lower its moisture content to the desired level. The pressure applied is dependent on the type of cheese, and it can be achieved using one of the following parameters.

Spring loaded or screw mechanisms

Hydraulic presses

Pneumatic systems or

Vacuum presses.

The former type is manually operated and hence the other systems are more common in mechanized cheese factories. One important aspect, which must not be overlooked, is the difference between airline pressure and the actual pressure applied to the cheese; the former pressure is actually lower. Since pressure is defined as a mass per unit area and the calculated actual pressure on the cheese takes into account

The air line pressure

The diameter of the cylinder head and

The surface of the cheese.

Therefore different cheese varieties are pressed at different pressures. In general, the cheeses are pressed in individual moulds or in bulk.

MOULD FILLING

The art of filling the cheese mould

The mould filling equipment is primarily designed to deliver a certain amount of curd to a mould and hence to produce cheeses, after pressing, of roughly the same weight. Such equipment could be incorporated either as a part of the curd handling system or in a position dependent on the variety of cheese produced.

The traditional wheel shaped cheese – The Emmental

The entire curd content from each vat is delivered to a mould after e-wheying , and the cheese maker has to alter the volume of the milk used in order to overcome the effect of seasonal variation on yield. Thus producing the cheese of roughly the same weight.

Cheddar and related varieties

The sequence of filling the salted, curd chips in to moulds is given below

• Tare of weight of mould
• First stage filling – up to 70% or more of the final weight of the cheese is delivered in to the mould
• Pre press the curd
• Second stage filling of the mould to the desired weight e.g. 20 kg and
• Transfer cheese moulds to the press

Two stage filing ensures that the pressed cheeses are uniform in weight. A different approach to the filling of cheddar cheese mould is the Press-n-fill Mk v, which is volumetric hoop filler. The salted curd is pre pressed in to a small, rectangular chamber of similar dimension to a 20 kg block shaped hoop.

While the discharged door is in the closed position, a horizontal guillotine cuts the curd and an ejector-ram pushes out the block and gives the curd a second pre press in the hoop. During the mould filling stroke, the mould liners are held in position by a clamp frame which also prevents the spillage of curd. The rate of filling is 3 x 20 Kg moulds per minute and the mould filing can be arranged either from the right hand or left hand side.

The amount of salt in cheese

The amount of salt retained in the cheese is governed by a multitude of factors, as given below.

• The level or percentage of added salt
• Method of salting (I.e. addition of salt to the milled curd or brining the pressed cheese);
• Duration of salting
• Moisture content of the cheese and
• Type of cheese etc.

Caerphilly cheese is the only British variety where the curd is salted at the rate of 1.0%. he cheese is dry salted while it is being turned in the press, and finally immersed in brine (i.e. 18% concentration) at 15-16°C for 12 – 24 h.

Percentage of Salt added	Cheese variety
1.6 – 1.8	Wensleydale
1.7 – 1.9	Single and double Gloucester
1.8 – 2.0	Cheshire, Cotswold, Derby, Dunlop, Kingston and Leicester
2.5 – 3.0	Cheddar

Cheese brine is a sodium chloride solution and its concentration is expressed either as percentage NaCl (w/w) (e.g. saturated brine is 35% NaCl) or Baume. The brining conditions of the Swiss, Italian and Dutch cheese may vary slightly.

SALTING OF CHEESE

SALTING EQUIPMENT

· The salting should be completed in an atmosphere isolated from any humidity in order to avoid the ingress of moisture to the metering device and thus the changes in accuracy of salting. The salting equipment in the Alf-O-Matic operates as given under:

· Warm, dry air transfers the salt from storage to a salt metering belt;

· Hot air passing through the valve transfers the salt to a stainless steel, oscillating distribution tube to be spread on to the cheese curd. The oscillating pipe is driven by an electric, geared motor;

· The amount of salt added is controlled by a floating sensor that determines the depth of the milled curd and actuates the salt metering device either to increase or decrease the salt dosage in line with the height of the milled curd; and

· Salt mixing and mellowing take place on conveyor where the curd chips are treated in a series of resting and turning periods. The residence time varies between 10 and 30 minutes.

The salt retention unit developed by Damrow Company has the following sequence of operations

· The curd chips are air conveyed from the cheese making equipment to a cyclone situated on top of the salt retention unit (SRU);

· The curd chips fall to the bottom of the cyclone and are delivered to a weighing belt and the air is vented out at the top of the cyclone;

· The curd chips enter the mixing drum where the exact amount of salt is added and mixed for a short period; the curd exits on to the mellowing top belt; the principle of using a mixing drum similar to the Bell Siro cheese maker system;

· Mellowing of the salted curd takes place on the two belts which are similar in operation to the DMC and

· At the end of the second belt, the mellowed curd leaves the SRU through the star valve and is air conveyed to a mould or heap filling station.

Classification of dairy starter

THE STARTER

Garvie and Tamime classified the lactic starters based on their ability to grow at different temperature as follows.

Mesophilic lactic starters

Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. lactis biovar diacetylactis, Lactococcus lactis subsp. cremoris, Leuconostoc mesenteroides subsp. cremoris.

Thermophilic lactic starters

Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus , Lactobacillus helveticus, Lactobacillus casei and Lactobacillus plantarum.

Miscellaneous bacteria

Propionibacterium freudenreichii subsp. freudenreichii, globosum. shermanii. The Propionibacterium shermanii is used in the manufacture of Swiss cheese.

The starter cultures may be preserved in the form of liquid, concentrated freeze dried or concentrated frozen at -196°C. The latter two types are suitable for DVI (direct vat inoculation) for the production of bulk starter or added directly to the cheese milk.

The production of a bulk starter is an important step in the successful cheese making process. During the recent past, the starter technology has shown tremendous improvement towards the ultimate objective of producing a pure and active culture.

The Nutrients of Cheese!

NUTRIENTS IN CHEESE

The nutrients present in cheese can be broadly classified in to proteins, fat, vitamins, minerals and salts. The proportion of these nutrients in cheese may vary depending upon the type of milk used for cheese preparation and the variety of cheese produced. Generally very hard, hard and semi hard varieties of cheese possess high levels of protein mainly casein, which is a major repository of essential amino acids present in right proportion required for human beings. The fat and carbohydrate fractions supply the much needed energy.

The milk carbohydrate, lactose, is present in solution and hence goes in to the whey portion during the cheese manufacture. Hence, the lactose content of the cheese is minimal and if at all present, it is mostly present in young cheese varieties and this is the substrate, which is usually acted upon by the starter bacteria during the fermentation process. This is the reason for no lactose intolerance symptoms in people suffering from this disease when they consume cheese.

Physicians generally warn their patients against consuming cheese because cheese is one of the fat rich diets. But this is generally considered as a myth because the recommended daily intake of cholesterol is 500 mg and the contribution of cheese towards the cholesterol content is only 26 mg and hence cheeses no longer pose any problem to the consumers by way of increased cholesterol content. Moreover, some cheese varieties have extremely low cholesterol level.

Apart from protein, fat and carbohydrate, cheese serves as a good source of vitamins but it is deficient in Vitamin C, which is lost during manufacture through whey. In order to avoid being deficient in Vitamin C, one has to supplement the cheese diet with some citrus fruits and vegetables. Though most of the water soluble vitamins get lost in the whey component during cheese making, sill the concentrated form of cheese serves as a good source of these vitamins. Cheese is again rich in bone forming minerals especially calcium.

Cheese - Its Uses!

Uses of Cheese

The use of cheese varies widely depending up on the country. For e.g. in Holland and France the cheese is consumed during any meal irrespective of whether it is breakfast, lunch or dinner. Whereas in England, cheese is not normally consumed during breakfast. The role of other dishes in improving the consumption of the cheese has to be mentioned here. For e.g. certain dishes such as hamburgers and pizzas greatly contribute to the excess cheese consumption in U.S and some parts of the Western Europe where these kinds of foods are becoming more popular.

Other factors

Other factors that influence the consumption pattern of the cheese include availability of different varieties of cheese in the market coupled with economic standards of the people. Health concerns make the people to choose cheese containing low fat. Advertisements in the print and visual media especially about different varieties of pizza generally boost the consumption of cheese. There is no ban on consumption of cheese by great religions and hence people of different religious faith welcome it. However, there are still some problems like kosher and halal products but these difficulties can be surmounted by using right ingredients and adopting approved manufacturing practices.

Cheese - How it was made accidentally

USE OF ANIMAL SKIN / STOMACH AS CONTAINERS

The traditional containers for carrying and storing milk used to be made from animal skins or stomachs. Clotting of milk was noticed when it is kept undisturbed in the containers made of animal skin due to the development of acidity as a result of bacterial activity. Another possible reason for the clotting could be ascribed to presence of clotting enzymes originating from stomach. During the process, a soft coagulum was formed and some of the liquid portion (called whey) was absorbed in to the skin, which later evaporated. The coagulum thus obtained was later concentrated further by squeezing and drying in the sun.

The product i.e. cheese obtained was found to have a better keeping quality than the original milk owing to increased concentration of lactic acid which prevented the growth of contaminating type of bacteria that resulted in severe off flavours. But a longer shelf life was achieved by dipping the concentrated curd in brine solution (salt solution), which added to the palatability of the product. The product was later known as ‘pickled cheese’ which is still manufactured in parts of Middle East. Cheeses such as Feta, Domiati, Akkawi, Halloumi can be cited as examples for these pickled varieties.

PICKLED CHEESE

The popularity of the pickled cheese slowly grew within the eastern Mediterranean region and it spread to other parts of the world especially to the west in the Europe. The tradesmen from these countries considerably helped in spreading the popularity of pickled cheese. As the pickled cheese gained popularity and became an acceptable dairy product in Europe, efforts were made to know its manufacturing technique and produce it locally in Europe. Later as the dairy industry made rapid strides, Europe saw the establishment of many advanced processing dairies. Some modifications were made in the cheese preparation, especially with regard to preservation of cheese in brine solution (partial brining was followed) in order to suit the prevailing temperate climate of the Europe. For e.g. Development of a new variety of cheese known as ‘Dutch Cheese’. Some times dry salting was resorted to because the curd produced was much drier.

Because of the continuous change in the manufacturing procedure to suit the local taste, the initial soft variety of cheese gave birth to hard pressed variety cheese or simply hard cheese. The advantage of hard cheese is that they can be stored for a longer duration at higher ambient temperature with out spoilage. Classical of the hard cheese is ‘Cheddar cheese’ and cheese developed in other British territory.

History and origin of Cheese Making

Cheese making is one of the ancient methods followed by the mankind the preservation of highly perishable and nutritional foodstuff like milk and converted in to a product which will be least susceptible for deterioration. Although the exact origin of cheese cannot be determined but from the archaeological evidence available with us, we can trace the origin to 6000 – 7000 B.C. A famous quote from a philosopher says

“The continued existence of man was primarily influenced some ten to fifteen thousand years ago by change in his way of life from being a food gatherer to a food producer”.

It can be inferred from the above quote that the transition from gatherer to producer was gradual and took place at different parts of the planet during different time intervals. During this period, domestication of animals is one of the important incidences of civilization. Man started to utilize the milk of domesticated animals such as cow, buffalo, goat and sheep.

Concentration, drying, fermentation, and salting are some of the methods of preservation of perishable commodities like milk known to the earlier mankind. Cheese is without doubt, a fermented dairy product, and in addition to the fermentation process, it is concentrated and salted. The earliest origin cheese can be traced back to the Mediterranean region in the Middle East.