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Milking
Milk out the udder regularly from the day of calving. Milk can be used for usual
human consumption from the 3rd or 4th day onwards. Animals producing more than 12
kg of milk per day can be milked 3 times a day. Keep the intervals between milking
almost equal (> 6-8 hours).
Take care to have clean practices during milking. Wash the udder properly and mop
it with a clean towel. In organised farms machine milking can be used.Use only properly
cleaned utensils for milking and storage of milk. Keep the surroundings clean and
free from dust. Take care that dung and urine do not splash into the milking pail.
Milking process should be completed as fast as possible because the effect of letting
down remains for about 5-6 minutes only. The udder should be completely milked out
at each milking.
Source of contamination of milk and control measures
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Source of contamination
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Control measures
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Exterior of udder
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Wash and wipe udder.
Clip the hair around udder and flank
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Interior of udder
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Check for mastitis using strip cup
Discard foremilk
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Air and dust in cattle shed
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Avoid dusty environment at milking time
Use small top milk pail
Keep milk covered
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Flies and other insects
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Eliminate breeding places
Control flies and insects with insecticidal sprays, repellents.
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Milker
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Practice clean habits,
do not use lubricants on the teat.
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Utensils
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Clean, sanitise and dry before use.
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Milking machine
Milking machine
Milking of cows can be done by machines. These work on the principle of negative
pressure. A vacuum pump sucks air out of the system. The teat cups are attached
to the teats after letting down. Due to sucking action of the machine negative pressure
is produced around the teat and milk flows out. From the teat cups the milk is drawn
into milk tanks or milk cans through tubes.
The main advantage with the milking machine is that labour can be saved. Also, as
the milking can be done quicker, the high yielders can be milked completely. Contamination
of milk also can be reduced as the milk does not come in contact with outside objects.
Care of Milk
Immediately after milking the milk should be transferred from the shed because milk
is capable of absorbing odours from the atmosphere. Straining through cloth, wire
gauze, plastic sieve is done to remove large particles of foreign materials like
straw, hair, insects, grass, dust etc. After each use the strainer should be washed
and sanitized.
Cooling of Milk
The scientific reason for the cooling of milk is to inhibit multiplication of bacteria.
A temperature of about 5oC will maintain the milk in this state. Cooling
is done by various methods in large dairy. Under farm conditions the milk cans are
kept in a tank containing cold water, the level of water in the tank being above
the level of milk in the can. Milk should be transported to the collecting or selling
point within four hours under the climatic conditions prevailing in Kerala. Delay
in this, without proper cooling will result in development of acidity and curdling
of milk. Transportation is done in cans. Can should be full to avoid agitation and
churning.
Various metals and their alloys are used for the manufacture of dairy utensils.
Metals like iron, copper etc. are not suitable because they are soluble (in traces)
and produce undesirable chemical changes resulting in odd flavour and bad taste.
Heavily tinned copper, galvanised iron and 18:8 chrome nickel steel are quite satisfactory
but they are very costly. Aluminium and aluminium alloys are the best under our
conditions. They are comparatively cheap, quite durable and free from action by
milk constituents. They can be easily cleaned and sanitised. The most important
aspect in the production of high quality milk is the cleaning and sanitation of
dairy utensils. The dairy utensils should be cleaned immediately after use and dried.
This will avoid the accumulation of milk residues, which result in bad odour, accumulation
of milk stones, crypts, rust etc. on the can. The following procedure should be
followed.
The utensils should be rinsed with clean cold water 2-3 times till the rinsed water
is almost colourless. Alkaline detergents are used if hand washing is practised.
The concentration should be adjusted so that it will not affect the hand. Detergent
powders available are mixtures containing sodium carbonate and other cleaning agents
like sodium hexametaphosphate, trisodium phosphate, sodium metasilicate etc. These
ingredients should be selected depending upon the metal of the utensil.
Sanitation is done to kill all disease producing micro organism. The process of
sanitation can be done by boiling water, steam or chemicals. Steam jet may be directed
into the can for 2-3 minutes. Boiling water should be poured into the can and kept
closed for 30 minutes. The temperature of the can should be above 85oC.
Chemicals such as Hypochlorites (Sodium and Calcium hypochlorites) are used for
chemical sanitation. Their strength is based on available chlorine. A strength of
200 ppm (available chlorine) for 2 minutes will be quite satisfactory. Quaternary
ammonium compounds (50 ppm) and iodophores (50 ppm) can also be used. The residues
of these chemicals if present, may affect the growth of desirable microflora used
in fermented milk products.
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