The following cheese-making operations are for making a firm-bodied cheese (Saint Paulin or Gouda type), a cheese most often produced in the developing countries and one which is relatively easily made to standard.
The various steps of the cheese-making process should be adapted to climate, equipment available and consumer preferences.
Steps in making a “Saint-Paulin/Gouda” type cheese
|• Hand-operated separator||Reception - Filtering|
|• One vat for pasteurization and cheese-making||Pasteurization (63°C for 30 minutes)|
|Cooling (32 – 35°C)|
|Inoculation (rennet; starter culture; calcium chloride)|
|Cutting the coagulum and stirring|
|Drawing off part of the whey|
|Addition of water or brine|
|• Moulding table||Moulding|
|• Press||Pressing (1 to 5 hours)|
|• Brining tray||Salting in brine|
|• Ripening cellar||Turning and ripening (at least 2 weeks)|
The producers' milk is first filtered and then poured into the one-step “pasteurization/cheese-making vat”. After filtering, a portion of the milk is passed through the separator to remove the required amount of cream.
The milk used for cheese-making is standardized to a level of fat content of some 26 g/l. The separator can be a source of contamination, and it is therefore preferable to standardize before pasteurization rather than after.
The milk is pasteurized at low temperature in the double-walled vat at some 63°C for about 30 minutes. The source of heat can be gas or electricity or even fuelwood. The milk is then cooled to a temperature of 32–35°C by circulating cold water through the jacket of the vat.
The lactic acid bacteria should be added at a rate of 1 to 2 litres per 100 litres of milk 15 to 20 minutes before renneting.
The rennet (at a strength of 1/10 000) is added at a rate of 20 – 25 ml of rennet per 100 litres of milk. This is the time to add, if necessary, calcium chloride (5–50 g per 100 litres of milk).
Following this, flocculation time is from 10 to 15 minutes, and total clotting time is from 15 to 40 minutes.
The curd is cut into regular grain-sized pieces. The first stirring should be carried out with both the curd grains and the whey, and should last from 5 to 10 minutes.
Drawing off the whey (lactose removal) consists of extraction of a portion of the whey (from 20 to 60 percent), followed by the addition of an equal amount of water at a temperature of 30 to 35°C.
Potassium nitrate may be added at this stage of the cheese-making process.
The second stirring, with moderate shaking of the curd grains in the diluted whey, lasts 10 to 20 minutes.
The curd and some whey are then put into cloth-covered moulds. These moulds may be made of wood, stainless steel or plastic.
Mechanical pressing lasts from 1 to 6 hours. During this operation, the cheese mould will be turned over 2 to 4 times.
The cheese is salted in saturated brine at a temperature of 10 to 14°C. Brining time varies according to the volume of cheese. A Saint-Paulin cheese weighing from 1.5 to 2 kg and with a diameter of 20 cm, is salted for about 8 hours.
Working out the curd lasts 2 to 3 days, at a temperature of 10 to 12°C and a humidity rate of 80 to 85 percent.
The cheese is placed on wooden shelves to ripen for at least 15 days at a temperature of 10 to 16°C with a humidity rate of 90 to 95 percent.
Prior to sale, the cheese can be covered with a protective film of wax.
If the cheese processing unit produces very large cheeses, they should be cut into 100 – 200 g slices prior to sale, and wrapped in greaseproof paper.
a) When standardized milk is used to make cheese, there will inevitably be excess fat in the form of cream.
Often it is advantageous for the cheese unit to sell this surplus fat as fresh or acidified cream, both of which are more profitable than butter. In rural areas, however, the market for cream is often quite small and the cheese unit is obliged to make butter, a product of longer shelf life.
b) If the cream is to be sold as it is, it should be pasteurized before packaging. Experience has shown that a pasteurization temperature of approximately 95 – 98°C for 30 seconds destroys germs satisfactorily and inactivates enzymes while preserving the organoleptic qualities of the cream.
After pasteurization, the cream is packaged in plastic bags or tubs and kept in a refrigerator.
The fresh cream is usually sold with a fat content of about 40 percent.
Acidified cream is sold with a lower fat content - 30 – 35 percent.
c) To make butter, cream is cooled to the lowest possible temperature. The cream is then stored until enough is obtained to make into butter. Cream stored in this way acidifies automatically, after which it is churned.
After filling the churn, the following steps are taken:
The churn is rotated at 25 – 35 revolutions per minute (rpm) for 5 minutes.
The churn is stopped and if necessary the gases released.
The butter is churned again at 25 – 35 rpm for 35 to 45 minutes.
The buttermilk is poured off into plastic pails.
The same amount of cold water as the amount of buttermilk which has been removed is added, and the mixture churned at 10 – 15 rpm for 5 minutes.
Water is drawn off.
Rotation at 10 – 15 rpm for 10 to 20 minutes.
The butter is removed.
The butter is worked with a butter worker for 5 minutes, compressed into a butter mould, and packaged in greaseproof paper. Alternatively, after working, it is placed in plastic tubs.
The butter can, if required, be salted as it is worked.
This operation may be regarded as the standard butter-making process since a number of variations are possible. Non-acidified cream can be churned, in which case the product is called sweetcream butter. Some butter-makers wash the butter twice and in some cases the butter is not worked at all.
The larger butter units usually pasteurize the cream, followed by the re-inoculation with selected lactic starter cultures for ripening. This method produces a cultured butter commonly called lactic butter.
|Diagram of lactic butter-making|
|Inoculation with lactic starter culture|
|Storage and marketing.|
Buttermilk is a by-product of the butter-making process. It is highly nourishing, hence the interest in promoting the product for human consumption.
Buttermilk quality depends greatly on the butter-making technique used.
Buttermilk can be packaged after only one filtration. It should be packaged in plastic bags.
Buttermilk can also be ripened. While the buttermilk is still in the pail, cheese-making starter cultures (approximately 2 percent) are added, and the product left overnight at room temperature before packaging.
Steps in yoghurt-making are as follows:
|Skimmed or standardized milk|
|Cooling to 42 – 45°C|
|Inoculation (approximately 1%)|
|Packaging in tubs|
|Incubation 42 – 45°C for 2 – 5 hours|
Pasteurization and cooling are done in the cheese vat, or in a pan for smaller quantities.
For yoghurt-making, the dairy unit needs to have a large refrigerator or small cold storage area - this also applies to cream and butter. Another essential investment item is an incubator, and perhaps a hand bottle-capper. Yoghurt is usually sold in plastic tubs or in cartons of 120 or 125 ml.
The yoghurt-making process increases the amount of cream available. Thus the decision to produce yoghurt should be preceded by a cost benefit analysis.
Another technique is to let the yoghurt clot in the vat. It is then stirred prior to packaging.
The technology is very simple:
|Cooling to 20 – 25°C|
|Addition of lactic acid bacteria|
|Stirring for a few minutes|
|Ripening (12 – 24 hours)|
This technology corresponds to the traditional process, and the product is in demand as the base used in preparing “porridge”. The processing unit's main consideration in this technique is that the milk is pasteurized and that both quality and hygienic standards are met.
Fermented milk being sold directly at the processing unit does not need to be packaged. The fermented milk is sold from the can, and is ladled into containers brought by local purchasers.
No specific equipment is required to make fermented milk. It is, however, advisable to allow for a large refrigerator.
Melting emulsification has traditionally facilitated the incorporation of sub-standard cheeses, as well as cheese trimmings, into products for sale as processed cheese.
The usual presentation for processed cheese is as a spread, packaged in plastic rolls or aluminium-wrapped in bite-sized portions. While the latter requires costly equipment to mould and package the cheese, processed cheese spread in plastic rolls offers an attractive approach for small dairies where second-quality cheeses, or cheeses with a manufacturing defect are readily available.
The product can be packaged in glass or plastic tubs, or otherwise wrapped in aluminium.
|Steps in processed-cheese making|
|Derinding or scraping|
|Addition of emulsifying salt|
|Cooking (10 min. of which 2 at 90°C; sometimes sterilization)|
|Packaging when the cheese is still liquid|
Commercial processed cheese preparations are highly diversified, as it is possible to add a variety of ingredients: flavourings, mushrooms, nuts, meats, etc. Packaging while the cheese is liquid, allows great variety of shapes and weights in the finished product. No specific equipment is required to make processed cheese, the only indispensable item being a pot in which to melt the cheese.
The simplest solution is a feedback system to return this product to the milk producers or to industrial-scale pig farms.
The quantities available are usually not sufficient to justify processing the whey and using it for human consumption. However, the nutritional value of whey is such that it can be used as a drink or as raw material in making certain whey cheeses such as Mysost etc.
Cleaning consists of removing all visible or invisible dirt from the surface. This surface can thus be described as clean.
Disinfection involves eliminating or killing micro-organisms.
Effective cleaning is absolutely essential for the equipment, installations and premises used for cheese-making, and the cheese-maker needs to pay special attention to this item.
After each use, all equipment and utensils: pails, cans, filters, pans, trays, tables, ladles etc., must be vigorously and meticulously cleaned. This is essential for successful cheese-making as the equipment is the main source of contamination by harmful germs. Simply rinsing with cold or lukewarm water is not sufficient. This is because a very thin film of residues or wastes from the clotting process sticks to the surfaces of the equipment which has come into contact with milk, whey or curd.
To eliminate these residues, an alkaline or acid detergent solution must be added accompanied either by vigorous brushing or agitation of the soaking solution to remove the residual film or wastes.
It is recommended that the equipment be soaked immediately after use in a vat filled with water.
Correct cleaning of dairy processing equipment should include the following operations:
Soaking the equipment in a vat filled with preferably warm water to help remove spots and stains;
rinsing to remove any remaining spots and stains;
brush cleaning with a hot water solution to which alkaline detergent has been added. An acid-based detergent should be alternated occasionally with the alkaline detergent, particularly in areas where the water used for washing is very hard;
rinsing in chlorinated water to kill dangerous germs. With a glass 3/4 full of bleach (sodium hypochlorite solution) of 12° chlorine for every 10 litres of water, all germs can be destroyed by allowing adequate exposure time;
the equipment and utensils are drained in a dust-free atmosphere to avoid contaminations.
In remote parts of the country, it is sometimes difficult to find detergents. Where this is so, the utensils after cleaning can be dried in the sun to disinfect them.
The layout and design of the dairy unit should be planned in such a way as to allow those responsible for processing operations to work under the confortable, safe and hygienic conditions.
Indicated below, as an example, are the times necessary for each operation involved in processing cheese from 150 litres of milk:
|•||filtering, checking temperature, preparation of coagulation, renneting||60 minutes|
|•||moulding, turning||80 minutes|
|•||demoulding, salting, setting on trays||60 minutes|
To this total of approximately 4 hours, the time required for packaging, labelling and packing the cheese for sale should be added.
The dairy unit must be designed to provide a rational layout to allow the cheese-maker to work efficiently. The following diagrams show several floor plans for village cheese-making.
Plan No. 1
Cheese factory handling 500 litres of milk per day
Plan No. 2
Cheese factory handling 600 litres of milk per day
|Scale I: 75|
|Cheese-making room||:||33 sq.m|
|Ripening room||:||22 sq.m.|
Plan No. 3
Plan No. 4
Dairy plant handling 2 000 litres per day