Quality Aspects of Milk and Milk Products

The quality aspects are important in reference to milk and milk products because of:

(a) Milk is perishable in nature: We know that milk is a biological product which is easily susceptible to spoilage from the time it is drawn from the udder of the animal. The perishable nature of milk demands due care to be taken in its handling to prolong its life. In addition to the spoilage brought by microbial fermentation, milk or its products can easily become the medium for transmission of diseases.

(b) An essential part of diet plan: Milk is almost a complete food and is preferred by our vegetarian population. Milk and milk products form an essential part of dietary plan. The two well recognized terms in this context are: “Milk and Public Health and Safeguarding the Milk Supply”. These aspects have been discussed here. A good quality milk is the one which satisfies the following requirements:

 (a) Wholesome and pure

(b) Free from sediment and foreign matters

(c) Good normal flavour

(d) Low in bacterial count and free from pathogenic microorganisms

(e) Free from antibiotics residues, pesticide residues and heavy metals

(f) Reasonably long shelf life and

(g) Nutritional components retained in the normal state

(c) Export potential: Our country being the number one in milk production in the world has the potential to export various milk products, particularly the indigenous dairy products and milk based sweets like Rasogolla, Gulabjamun, Burfi, milk cake, etc. to the third world countries provided that the quality of our products is up to the international standard and these are free from adulterants and toxicants like animal drug residues, pesticide residue, heavy metals, etc. Milk and milk products are very prone to different type of adulterations. The quality aspects play an important role in ensuring the consumers that the food they are eating is wholesome and free from adulterants and toxic substances. Let us know about “Milk and Public Health”, “Safeguarding the Milk Supply” and “Adulteration of Milk and Milk Products” to appreciate the importance of quality.We have already been introduced to these aspects in the course 1 titled “Milk production and quality of milk”.

i) Milk and public Health: There are many possibilities for contamination of milk during its journey from production point to the consumers end. The different sources of infection and corresponding important diseases are enlisted here.

(a) Infection of milk directly from the animal (Cow/ buffalo): These diseases are essentially of bovine origin. The causative organisms enter the milk through the mammary glands or through faecal contamination, and may cause a diseased condition in person who consumes the milk. Examples are: Bovine tuberculosis, undulant fever, etc.

(b) Infection from man to cow and then to milk: These diseases are essentially human, but can become established in the cow’s udder. Examples: septic sore throat; scarlet fever; diphtheria;etc.

(c) 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 by patients. Examples: septic sore throat; scarlet fever; typhoid fever; dysentery, gastroenteritis, diphtheria, etc.

(d) 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, insect and dust. Examples: typhoid, dysentery or diarrhoea, etc.

ii) Safeguarding the Milk Supply: It is desirable that milk being consumed by human being should be clean, wholesome and safe. We know that cleanliness implies freedom from extraneous matter (such as manure, dust etc) and safety means freedom from pathogenic microorganisms. The wholesomeness implies that no nutrients from the product has been removed or destroyed. The sanitation of 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) ensuring the health of dairy cattle by various control measures;(ii) safeguarding the health of employees by regular medical examination; (iii) protection of the water supply from contamination by pathogenic organisms;(vi) flies and their control, etc. (b) Pasteurization of milk, so as to kill all pathogenic organisms and avoidance of any post-pasteurization contamination.

iii) Adulteration of Milk and Milk Products: The adulteration of milk and milk products can be defined as the process by which the quality or the nature of product is adversely affected through the addition of a foreign or an inferior substance and the removal of a vital element such as fat from milk. Adulteration may be intentional or unintentional (contamination). Adulteration in our country is very common in case of milk and milk products due to their higher price compared to plant foods. You must be aware about news paper reports about preparation of “synthetic milk” and “turning animal fat into ghee”. As a quality control team member it is our responsibility to ensure availability of unadulterated products to the consumers. Milk and milk products are adulterated with the following substances.

Unintentional adulteration or contamination: The unintentional contaminants may include antibiotic residues, pesticide residue, heavy metals and toxins secreted by different microorganisms.

Intentional adulteration: Intentional adulteration of milk and milk products is done to make more profit by the unscrupulous traders. Milk is adulterated either by the removal of its fat or addition of water, glucose, starch, urea etc.In the same way milk products are adulterated with the addition of vegetable or animal body fat, starch, arrowroot, etc.

iv) Role of quality control in preventing the adulteration of milk and milk products: Despite of the advantages of modern technology and sophisticated instrument, the menace due to adulteration/ contamination of milk and milk products is one of the leading causes of sickness or death. Food borne diseases, range from acute gastroenteritis to precancerous/ cancerous stage. Consumers are therefore offered tips in ascertaining quality of food by quick and simple tests for detection of common adulterants. National Dairy Research Institute, Karnal, has developed a platform test for detection of adulteration of milk with“synthetic milk”. The platform test is colour based test and provides the results within 5-10 minutes.

The control must take place at the point where the contamination occurs. For examples, dairy plants can make acquaint the farmers about the pricing advantages associated with quality of milk, rejection of milk and penalties linked with the adulteration and safe limits about the use of antibiotics and pesticides at farm, so that the residual limits are not exceeded in the milk supplied.

Quality Initiatives: Quality initiatives taken up in the dairy cooperative sector includes a massive awareness programme of the Government of India on Clean Milk Production (CMP) covering village Dairy Cooperative Societies (DCSs) across the country under the scheme “Strengthening infrastructure for Quality and Clean Milk Production”. Through a range of informational and educational inputs, including a book titled “Doodh Ki Kahani Gai Ki Zabani” published in Hindi and in 10 other state languages, producers are made aware of hygienic milking and milk handling practices. Similarly various other schemes supported by different Ministries are also under operation. International dairy federation (IDF) and Food and Agriculture Organisation (FAO) has also published “Guide to Dairy farming Practices” focussing on the farm practices within the integrated safety and quality assurance system to ensure profitability with responsibility of protecting human health, animal health, animal welfare and the environment.