LPT 311: Milk and Milk Products Technology (1+1)

VARITIES / DEFECTS IN CHEESE

Cottage cheese

• Thisis a soft, unripened cheese usually made from skim milk. It has mildly acid flavour and consists ofsmall particles or flakes or curd, which have a meaty consistency. Creamedcottage cheese has cream mixed to it upto 4 % level. Both varieties are saltedalways.
• Cottagecheese can be prepared by both, direct acidification and by starter culturemethods. In direct acidification method, any food grade acid, phosphoric,lactic acid etc., are used.  

Method of manufacture

• Receiving (pasteurized) milk
• Adding calciumchloride
• Adding starter culture(lactic cultures)
• Adding rennet (0.01 %) Setting ( 30ºC)
• Cutting Cooking (upto 46ºC,over 2 hrs)
• Drainage of whey Washing and drainingthe curd
• Salting
• Creaming
• Packaging and storage

Details of manufacture

• Receiving of Milk
• Theskim milk should be fresh, sweet, low in fat and bacterial count and clean inflavour. It should be pasteurizedimmediately after separation preferably by LTLT method as it produces softercurd.
• Adding calcium chloride
• Calcium chloride is generally added to the skim milk at the rate of 1 mlsaturated solution per 100 liters of milk, with the objective of increase theconcentration of calcium for better setting
• Adding starter culture
• A high quality starter consisting of either S.lactis, S.cremoris,S.diacetylactis, L.dextranicum, etc., singly or in combination is then added at1 to 2.5 % levels and thoroughly mixed into it.
• Adding rennet
• Rennetis added at 2-2.5 ml per 1000 litre of milk. It is diluted with water upto 40times with water before adding.
• Setting
• Thetemperature is set around 29-32ºC
• Cutting
• Themost desirable acidity of whey at cutting is approximately 0.5 % (pH 4.6-4.7).The whey should be clear and free from curd particles.
• Cooking
• This begins soon after cutting and continues foran hour or two until the temperature reaches 45ºC or until the curd becomeshard enough for removal of whey. Stirring during cooking is done very gently and at a minimum rate.
• Drainage of whey
• Wheyis removed when the curd cubes no longer have a ‘soft center’ and when ahandful of them squeezed gently show slight elasticity.
• Washing and draining
• The curd is washed after removing all the whey to produce desiredfirmness and mildness in flavour. Thewash water is at the temperature of 21ºC and after soaking for 15 minutes thewater is drained. Second washing is done with water at 16ºC. Draining should be thorough; the cubes areplaced in draining rack with perforations at the bottom, which can be wheeledinto cold store rooms.
• Salting
• This is done when the free moisture has been drained from the curd. Salt can be added to the curd in the vat, orit can be dissolved in the cream for creamed cottage cheese. Salt is added @ 1 % of curd weight.
• Creaming
• This is done immediately after draining, if the product is to packed atonce. Holding the curd overnight in acold room before it is creamed makes it more firm when creaming. The amount of 20 % cream added is @ 4 % level of the curd weight.
• Packaging and storage
• Cottagecheese, creamed or uncreamed, may be packed in waxed / polythene-coated papercups or in polythene bags. Storage is at 5ºCor less.

Yield

Theyield of cottage cheese before creaming depends essentially on

• The composition of the milk
• Manufacturing losses
• Moisture content of the cheese
• Approximately yield of cottage cheese is 15 %.
• Keeping quality of cottage cheese
• Thekeeping quality is short even under refrigerated conditions (5-10 ºC).

Processed cheese products

• Processed cheese is produced by blendingshredded natural cheeses of different types and degrees of maturity withemulsifying agents, and by heating the blend under a partial vacuum withconstant agitation until a homogeneous mass is obtained. In addition to natural cheeses, other dairyand non-dairy ingredients may be included in the blend.

Advantages of processed cheese

• Reduced refrigeration cost during storageand transport, which are especially important in hot climates
• Better keeping quality, with lessapparent changes during prolonged storage.
• Great diversity of type and intensity offlavour, e.g. from mild to sharp, native cheese flavour or specific spices.
• Adjustable packaging for various usages,economical and imaginative.
• Suitability for home use as well as forsnack restaurants, e.g. in cheeseburgers, hot sandwiches, spreads and dips forfast foods.

Processed cheeses are characterizedessentially by composition, water content and consistency; according to thesecriteria, three main groups may be distinguished; processed cheese blocks,processed cheese foods and processed cheese spreads. More recently established sub-types ofprocessed cheeses are: processedcheese slices and smoked processed cheese. The first sub-type belongs to the category of processed cheese blocks,while the second could be either block or spread. In addition, another group of processedcheese products should be mentioned, i.e., processed cheese analogues,which are usually based on vegetable fat-casein blends. Finally, the most recent development incheese processing is processed cheese with a completely new look, i.e. naturalcheese-like appearance. Developed in France, thisproduct has an open texture, similar to traditional cheeses, with eyes of about0.5 mm in diameter.

General defects in cheese

Name of the Defect	Causes	Prevention
Colour
Acid cut/bleached/faded	Excessive acid development in cheese curd	Optimum acid development in cheese curd
High/Unnatural	Excessive addition of colour to cheese milk	Optimal addition of colour to cheese milk
Mottled	i)combining cheese from two lots ii)uneven acid development in cheese curd	Avoiding it and even development of acid
Finish and appearance
Cracked Paraffin	Excessive thickness of paraffin coating on cheese	Correct thickness of paraffin coating
Lopsided / hill sided /misshapen	Incorrect filling and pressing of curd cubes	Correct filling and pressing of curd cubes
Rind rot	Excessive acidity and/or moisture in cheese before curing	Optimum acidity and/or moisture in cheese before curing
Body
Curdy/rubbery	i)low moisture content in cheese before curing ii)Low acid development in curd iii)over-salting cheese iv)insufficient cheddaring of cheese curd	Optimal moisture before curing Optimal acid development Optimal salt level Proper cheddaring
Texture defects
Fish eyes/yeast holes	Contamination with yeasts	Avoiding contamination with yeasts
Flavour
Bitter	Low quality milk Low quality starter iii) Excessive acid and/or moisture in cheese	By using good quality milk, starter and maintaining optimal acid and moisture in cheese

Uses of cheese

• Direct consumption as such or in sandwiches
• In the preparation of special dishes (added incut or grated form)
• In the preparation of sauce.