Measures for Clean Milk Production

In order to bring out considerable change in the prevailing situation throughout the country, a systematic approach is required for milk production and manufacturing of different products. Therefore, a multidimensional team work should be initiated in which the team workers will look into the areas of animal management, nutrition,health, microbiological aspects of the milk and milk products as well as the residues of other unwanted contaminations in the milk. This should first generate information on the base line for each aspect and identify the critical points during the process of milk production and processing.

The following measures should be taken care for the production of clean milk:

i. Animal Management at Farm Level
When milk leaves the healthy udder, it is relatively free from bacteria. While some contamination with bacteria from the milking environment and the equipment is inevitable, the total bacterial count should be lower than 3 million/ml or otherwise,it will lead to significant degradation of the fat, protein and lactose causing off-flavour and would significantly reduce the flexibility in processing the milk. Although pasteurization reduces the bacterial count, it can not destroy the bacterial spores,which germinates again. Moreover, there are some bacteria producing toxins that survive even at pasteurization temperature and remain in the milk products too.The animal management involving the feeding aspects of the animal as well as health and practices related to housing and environment at farm level are very important.

a) Feeding: Feeding of milch animals should be done an hour before milking. At the time of milking, for the purpose of keeping cows busy, provide only concentrates which are less dusty. Feed and feed ingredients should meet minimum safety standards. These should only be produced, stored, marketed and used if they are safe and suitable. The presence of unsuitable substances such as industrial and environmental contaminants, pesticides, radionuclides,persistent organic pollutants, pathogenic agents and toxins/mycotoxins in the feed should be identified. Feed additives and veterinary drugs used in medicated feed should be critically assessed for safety aspects before using. Therefore,improper procurement, manufacture and handling of animal feed can result in the introduction of pathogens and chemical hazards, which can affect the safety and sustainability of milk.

Balanced feeding with appropriate quantities of green fodder, straw and concentrates having all essential nutrients and minerals is another important aspect required for quality milk production.

The points to be considered while feeding the milch animal are:

•  Feeds and fodders should be free from pesticides, insecticides, fungicides,herbicides, fumigants, aflatoxins as well as heavy metals.
•  Feed ingredients should be stored in moisture-free conditions. Rodenticides should be carefully handled.
•  Silage and wet crop residues should not be fed at milking place as it may impart foul odour to the milk.
•  Good quality straw and supply of adequate minerals and vitamins in feeds should be given high priority.

b) Housing: The housing and its environment are most often forgotten. Therefore,we need to look at where the cow is milked, where she is housed, and how she gets back and forth between these areas. The animal shed is one of the main sources of contamination. At the same time, a good shed protects animals against micro-organism as it keeps out other animals, people, wind, rain and excessive heat, all increasing the danger of contamination. Mud, urine, faeces and feed residues should regularly be removed from the shed. The shed should have proper drainage, sufficient lighting and ventilation. In very wet areas,sprinkling slaked lime over the surface will help to dry it out quickly. The milking area of the shed needs special hygienic attention. The floor of the milk shed should be swept with clean water and disinfected with one per cent bleaching powder solution. Facilities should be provided for a sufficient supply of safe and potable water for drinking, washing udders and flanks of the animals, utensils and milker’s hand etc.

The farmer needs to be educated to know how a well-constructed animal shed and well maintained surrounding help in keeping his animal disease-free.

•  The cattle shed should be well-roofed, sufficiently lighted, well ventilated,dry and comfortable with adequate elevation to avoid stagnation of water.
• It should not be a breeding place for pathogens, flies and mosquitoes.
•  There should be appropriate arrangement for disposal of animal waste in a manure pit or a biogas plant. Care should be taken to remove left over fooder and fodder lying on floor.
•  Proper arrangement of doors and windows with wire mesh.
•  Barns and holding pens have to be properly located.
• Piggery and poultry farming should be avoided in the premises of animal shed.
•  Control of flies and insects is important as they are potential source of transmitters of disease causing organisms.

Tips to evaluate a good housing system

•  Housing must be kept clean and dry 24 hours a day.
•  Proper ventilation and lighting
•  Controlling the environment during summer and excessive winter.
•  Allotment of proper space for each animal.

c) Animal Health: The pre-requisite of clean milk production is a healthy herd.The farmer should be educated and trained to adopt improved health care practices because only a healthy and clean animal can produce contamination free milk.

• Routine examination of cattle is necessary to assure that they are disease- free (TB, Brucellosis etc.) The animals suffering from contagious disease must be kept separate from healthy herd. Sanitary precaution to prevent and control the disease should be adopted.
•  Using inducer drugs should be avoided.
•  Check for udder wounds and mastitis. Avoid pooling of milk of the animals on drugs with the bulk milk until the animal fully recovers from illness.
•  Vaccination of animals against FMD, Anthrax, Hemorrhagic septicemia etc. should be done at least once a year.

ii. Somatic Cell Counts (SSC)

Mastitis is one such infection, which not only alter the composition of milk but also reduces the milk yield. Mastitis milk has low lactose, casein, fat and calcium and high amount of immunoglobulins and sodium. Such milk contains high number of somatic cell and pathogenic bacteria. Mastitis renders the milk unsuitable for human consumption and for production of cultured and fermented milk products. Infected udder can be source of a wide variety of micro-organisms.Somatic cell count (SCC) is being used as an index of the udder health and quality of milk. Any inflammation or injury to the mammary gland will increase SCC of milk. Due to this reason the monitoring of somatic cell secretion in milk helps to detect the sub-clinical mastitis. In addition, SCC in bulk milk samples also indicates the level of hygiene maintained at the farm. The milk having high SCC indicates some disturbance in the udder and should be discarded. To effectively monitor the udder health and the quality of milk, the milk samples should be checked at least at fortnightly intervals and if SCC values are found more than the prescribed standards, the necessary treatment of the quarter should be immediately given.

Somatic Cell Count is influenced by number of factors such as management of animal, health of animal and surrounding environmental of the animal. Milk is considered normal, if SCC are 1x10 6 cells/ ml or lower. The detailed criteria of normal and abnormal milk is given in beow Table.

Criteria to determine the normal or abnormal milk

In order to reduce effectively the SCC in milk, cleaning and regular removal of waste should be done so that the chances of bacterial growth and pests are minimized. Milk from the animals showing clinical symptoms of diseases should neither be mixed in bulk milk nor used for human consumption. The milking byres should have provision of fans and proper ventilation so that light does not become a limiting factor in milking operations.

iii. Cleanliness of Milking Equipment and Utensils

Milking equipments and utensils used at farm include a variety of equipment and containers including milk pail, milking machine, teat cup clusters, cans, milk pipeline,recorder, bulk tank, strainer, cooler, milk flow indicators, etc. These equipment pose a serious threat. The residual milk solids on such equipment sustain the growth of micro-organism and colonization of such micro flora results into formation of biofilm.

These biofilms can result into heavy contamination of milk during subsequent operation or use. Milk cans generally contribute thermoduric organisms while bulk tank and storage tank may facilitate the proliferation of psychrotrophs due to prevalence of cold temperature during holding of milk in these tanks.

Therefore, proper cleaning removes most of germs and parasites along with the dirt. The equipment and vessels coming in contact with milk should be thoroughly cleaned.

•  The milk vessels must be cleaned before and after each milking thereby rendering these bacteria free.
•  Detergents/chemicals used for cleaning of vessels, must be non-injurious to health like teepol. Use of ash or mud is not recommended.
•  The cleaned and sanitized vessels must be kept in an inverted position in a space.
•  Milking pail with dome shaped top should be used instead of open buckets or vessels by which milk contamination can be nullified to a great extent.

iv. Hygienic Milking Practices

Hygienic conditions of storage and transport equipments and storage temperature are the two key factors, which play a great role in deciding quality of raw milk.Air posses a lesser threat as a source of contamination in comparison to other sources like teat surfaces. Some organisms may enter during hand milking (falling in the milk pail) and machine milking (sucked along with air). In addition, the personal hygiene of the worker either at cattle yard or dairy dock must be taken into consideration to produce clean milk.

Hygienic practices during milking contribute to production of safe and suitable milk.

•  There should not be any floor sweeping (disturbances, noise etc.) at the time of milking for preventing pollution of air by dust/bacteria.
•  Milker’s should be free from communicable diseases and should wear clean clothes, nails trimmed and should neither eat or spit anything nor clean his nose.
•  Before starting the milking operation, the milker should clean his hands with soap, potable water and then wipe them with clean towel.
•  Clean the udder and teats with lukewarm water using a cloth before each milking.
•  The fore stripping should be collected in separate utensil/cup and should not be thrown on the floor, so as to avoid infections by the flies.
•  After milking the teats have to be dipped into a bacteriocide to minimize the risk of infection. The practice of dipping of fingers into milk and then wetting the teats to soften them is not recommended.
•  Milking should be completed within 6-8 minutes.
•  Wet milking (moistening the hand with milk or oil or water) is not encouraged.
•  Milk should be strained using a clean cloth or a strainer to remove sediment and other foreign materials. If cloth is used, it should be washed and dried daily.

v. Cooling of Milk

The provision of bulk cooling facilities at each centre under clean milk production programme encouraged by NDDB has been assured in order to have the bulk milk cooling tank for maintaining the bacteriological quality of raw milk by adopting clean milk production practices and immediate cooling of milk for onward journey to dairy dock. The reduction of time between milking and reception at the center, maintenance of low temperature of milk till it is received at dairy/chilling center through chilling interventions by providing bulk milk cooling tanks enhances the safety of quality milk.

The strategic advantage of producing clean milk is lost entirely if post milking handling is not carefully managed. The microbiological contamination is the major source of continuous deterioration of milk.

• To preserve the keeping quality of milk, it has to be cooled as soon as possible to a temperature below 5°C by storing in refrigerator or can be kept at cooler place.
•  The sooner the milk is cooled after removal from the udder, the better is the quality.
•  Bacterial growth is retarded by cooling and storing milk at 10°C or below within 2 hours of milking.
•  Delivery of milk to the factory should be as frequent and as early in the day as possible