It is well established that milk can be a potential carrier of disease producing organisms. Milk-borne epidemics have occurred in the past throughout the world. Unless proper precautions are taken, such outbreaks of milk-borne diseases can occur anywhere, any time, especially if raw milk is consumed.
Diseases, which are known to be transmissible through milk, are listed below, together with the manner in which they may enter the milk.
Infection of milk directly from the cow
These diseases are essentially bovine. The causative organisms enter the milk through the mammary glands or through faecal contamination, and may cause a diseased condition in persons who consume the milk. Examples; Bovine tuberculosis, Undulant fever or Malta fever, etc.
Infection from man to cow and then to milk
These diseases are essentially human, but can become established in the cow’s udders. Examples; Septic sore throat, Scarlet fever, Diphtheria, etc.
Direct contamination of milk by human beings
These diseases may be transmitted to the milk by direct contamination through human contact, either by carriers or patients. Examples; Septic sore throat, Scarlet fever, Typhoid fever, paratyphoid fever, Dysentery, Gastroenteritis, Diphtheria, etc.
Indirect contamination of milk by human beings
These are human diseases, the pathogenic organisms of which enter the milk through contaminated bottles or other utensils, water supply, insects and dust. Example; Typhoid or Paratyphoid fever, Dysentery or Diarrhoea, etc.
Safeguarding the milk supply
Whereas ‘cleanliness’ implies freedom from extraneous matter (such as manure, dust, etc.) ‘safety’ means freedom from pathogenic micro-organisms. For human consumption, milk that is both clean and safe is highly desirable.
The quality of the milk supply can be safeguarded in two ways.
a) Production and handling of raw milk in such a manner as to prevent its contamination by pathogenic organisms. This will require
I. Safeguarding the health of employees by regular medical examination.
II. Protection of the water supply from contamination by pathogenic organisms.
III. Flies and their control, etc. examples; ‘Certified milk’ ‘Grade A raw milk’, etc.
b) Pasteurization of milk, so as to kill all pathogenic organisms and avoidance of any post-pasteurization contamination.
Ag.
Technologies
(Dairy)
