Market Milk

Lesson 4. PRACTICES RELATED TO ANIMAL AND MILKING PERSONNEL

Module 3. Clean milk production

Lesson 4
PRACTICES RELATED TO ANIMAL AND MILKING PERSONNEL

4.1 Introduction

Milk is the most nutritious and complete food for new born infants and adult human beings. It is, therefore, a perfect growth medium for innumerable microorganisms including pathogens. Some common milk-borne infections and the pathogens causing them are listed in Table 4.1. Milk is also a potential source for chemical contaminants such as antibiotics and pesticides. The term ‘clean milk’ refers to raw milk from healthy animals, that has been produced and handled under hygienic conditions, that contains only a small number of harmless bacteria, is free from hazardous chemical residues and that possesses a good keeping quality without being heat-treated. As the raw milk quality prevailing in India is not good, there is much scope for the improvement in the quality of milk produced by making quality strategies for the post-production handling of milk.

The two basic principles that ensure safe handling of raw milk are 1) avoiding or minimizing contamination at various stages of handling raw milk and 2) reducing the growth and activity of microorganisms in raw milk. Knowledge of the possible unhygienic practices that lead to the gross contamination of milk will be useful in realizing the seriousness of the situation and in recommending strategies to improve it. Table 4.2 enlists the possible sources and extent of contamination that can occur in milk.

The possible undesirable practices that are prevalent may broadly be classified into four categories:

• Practices related to the animal: unhealthy animal, unclean body and udder of the animal

• Practices related to the milking personnel: unhealthy milker, unclean hands and clothes of the milker, unhygienic personal habits of the milker

• Practices related to the milking process: incomplete milking, wrong milking procedure, unclean vessels for milk collection

• Practices related to the environment: poor housing and feeding of the animal, unhygienic surroundings

Some of the common practices to ensure clean milk production are discussed below in detail.

4.2 Practices Related to the Animal

4.2.1 Health of the animal

• The animals should be examined periodically for udder and other infections.

• Infected animals should be treated by a qualified veterinarian.

• Animals suffering from infectious diseases should be isolated. Sanitary precautions to prevent and control the diseases should be adopted.

• Milk of the infected animal should never be pooled with the bulk milk until the animal recovers from the illness fully.

Table 4.1 Common milk-borne infections

No.	Infection	Causative pathogen	Disease/ disorder	Possible source of entry
1	Food infection	Salmonella typhii and related species	Typhoid, salmonellosis (food poisoning)	Dung
		Shigella dysenteriae	Shigellosis (dysentery)	Faecal contamination
		Streptococcus sp. (enterococci)	Septic sore throat, scarlet fever, food poisoning	Faecal contamination
2	Food intoxication: Bacterial	Staph. aureus	Food poisoning	Human beings
		Cl. botulinum	Botulism (food poisoning)	Soil, water, inadequate processing
		E. coli	Summer diarrhoea	Faecal contamination
		V. cholerae	Cholera	Water
	Fungal	Aspergilus flavus	Aflatoxicosis	Poor storage & handling
		Other toxigenic mold spp.	Mycotoxicosis
3	Toxic infection	Bacillus cereus	Food poisoning	Soil, water, inadequate processing
		Cl. perfringens	Gas gangrene	Soil, water, inadequate processing
4	Other milk-borne disorders (uncertain pathogenesis)	Aeromonas spp.	Food poisoning	Water
		Proteus spp.		Human intestinal tract, soil, water
		Klebsiella spp.		Enteric sources
		Pseudomonas spp.		Soil, water of cold regions
		Citrobacter spp.		Soil, water, sewage
5	Some other important pathogens	Listeria monocytogenes	Listeriosis	Soil, human beings
		Yersinia enterocolitica	Diarrhoeal disease	Water
		Campylobacter jejuni		Dung
		Vibrio parahaemolyticus		Water
6	Other milk-borne diseases: - Bacterial	Mycobacterium tuberculosis	Tuberculosis	Humans
		Brucella abortus

Table 4.2. Bacterial contamination of milk as influenced by different sources