Pashu Sandesh, 06 June 2019

Dr Pooja Patel *, Dr Mahender Milind Lakeshar and Dr Mamta Meena

Milk is nature's ideal and perfect single food both for newborn and mature human beings. Good quality milk is essential for the production of good quality dairy products, taste and flavour, free from pathogens and long keeping quality.

But because of its high nutritive value and high moisture content of milk, it also serves as a good medium for the growth of microorganisms. Milk is sterile when secreted into an uninfected udder. Their rapid growth, particularly at high ambient temperatures can cause marked deterioration, spoiling the milk for liquid consumption or manufacture into dairy products.

As such, it is essential that the milch animals should adequately be protected from diseases because the causative agents of these diseases may be either excreted into milk or they may contaminate milk through environmental contamination. Contamination can occur during and after milking.

Sources of contamination

• Udder and udder flanks

• infected Hands of the person doing the milking

• Dirty milking equipment

• Dirty vessels to store and transport milk

• The environment, e.g. chemicals and dust

• Disease or infection in the person doing the milking

Exclude milk from clinical mastitis cases to avoid high bacterial counts. Use mastitis control routines at each milking to reduce the proportion of infected cows and clinical mastitis cases

NEVER! Deliver milk of a cow treated with antibiotics, this milk is dangerous even for home consumption. The withdrawal period of milk of animals treated with antibiotics vary! The considered waiting (withdrawal) time is found in the instructions of use found in and on the packing materials of the medicine.

Good quality raw milk must be:

  1. Free from debris and sediment.
  2. Free from off-flavours.
  3. Low in bacterial numbers.
  4. Normal composition and acidity.
  5. Free of antibiotics and chemical residues.
  6. Produced by healthy cows 
  7. Handled by healthy people

Important points to consider for the production of clean milk and milk products are summarized below:

1. Personal hygiene

• Wash your hands and nails with clean water and soap before handling milk

• Wear clean over-clothes and gumboots while handling milk

• Never handle milk if you are suffering from a communicable disease or have an open sore or wound on your arms, hands, head or neck.

• Do not cough or sneeze near milk or milk containers

• Bathe or take a shower regularly

2. Disinfection of dairy equipment 

  • All equipment must be regularly cleaned and sanitized. Cleaning is the first step, i.e. removing dirt and residues. 
  • After cleaning, sanitization is done to remove micro-organisms. 
  • Water is not enough to achieve full sanitization, so chemicals have to be used, such as alkaline detergents (e.g. caustic soda or soda ash), acid detergents, sodium hypochlorite (or bleach at 80 ppm), chlorine, etc.

3. Udder washing:

  • washing by spraying water and wiping of teats
  • washing of teats with a cloth immersed in the warm disinfectant solution and drying with a dry cloth
  • Immersing of teats in disinfectant and wiping with a paper cloth.

Tips after milking

Mastitis is an udder infection that can occur due to many reasons. After milking the cow the sphincter in the teat tip is open. Bacteria that possibly cause mastitis can enter the udder easily. The sphincter will stay open for about an hour. Dipping the teats with a special teat dip right after milking can help to prevent udder infections. Next, to that, it will help to keep a cow standing for more than an hour directly after milking. In a zero grazing unit, it will help for instance to make sure fresh feed is available directly after milking for each cow. An eating cow is standing. At the end of milking using teat cream or teat dip is advisable.

4. Cooling milk:  The time from milk collection to cooling is very crucial. Bacterial multiplication is very slow during the first 2 hours. After that bacteria will multiply very fast, doubling every 20-30 minutes. If you are transporting unchilled milk, make sure the milk reaches its final destination within 2 hours from the time of milking. This is the secret to successful milk transportation.

 5. Heating: Pasteurization of milk involves heating it to 63°C for 30 minutes or 72°C for 15 seconds in order to destroy harmful microorganisms. Pasteurization kills more than 90 per cent of bacteria. 

6. Washing milk utensils:  After milking again washing of milk utensils should be necessary.

Milk-borne infection: an emerging public health issue - Milk has the potential to cause foodborne illness. Raw milk is also known to be associated with pathogenic bacteria which cause milk-borne diseases such as tuberculosis, brucellosis or typhoid fever, etc. Hygienic milk production, proper handling and storage of milk, and appropriate heat treatment can reduce or eliminate pathogens in milk. In many countries, milk processing factories are required by law to pasteurize milk before selling it to the public. Many consumers also routinely boil milk before drinking it to protect themselves from milk-borne diseases.

Hygienic milk handling includes using clean equipment, maintaining a clean milking environment, observing good personal hygiene and preserving the quality of milk during storage and transportation to the consumer or processing plant.

Dr Pooja Patel *, Dr Mahender Milind Lakeshar and Dr Mamta Meena 

  1. Assistant Professor, Department of veterinary microbiology, Apollo College of Veterinary Medicine, Jaipur (Rajasthan)
  2. PhD scholar, Department of veterinary microbiology, RAJUVAS, Bikaner (Rajasthan)
  3. Assistant Professor, Department of veterinary pharmacology, Apollo College of Veterinary Medicine, Jaipur (Rajasthan)

 Corresponding author: Dr Pooja Patel, dr.poojapatel007@gmail.com