1. Is raw milk safe for consumption?
The raw milk is not safe for consumption. Unless and until the health condition of the milch cow and the environment in which the milk is produced and handled till it reaches the consumer is definitely known, it is always advisable to drink pasteurized milk or boiled milk from the safety point of the consumer.
2. What is pasteurization?
Pasteurization refers to the process of heating each and every particle of milk to at least 63°C for 30 min (LTLT method) or 72°C for 15 sec (HTST) or to any approved temperature-time combination which is equally efficient in an approved and properly operated equipment. Immediately after pasteurization, the milk is invariably cooled to 5°C or below.
3. Why does raw milk curdle when heated after standing at room temperature for considerable period of time?
Milk contains a variety of microorganisms, which are capable of converting lactose present in the milk to lactic acid, increasing the acidity. When the milk is stored at room temperature (30-37°C) for considerable period of time, it provides ideal temperature for the growth of most of the spoilage causing organisms and in turn increases the acidity. When the acidity increases beyond 0.20% lactic acid, the milk clots on boiling or heating.
4. Why does milk appear white?
The normal milk ranges in colour from yellowish creamy white (cow milk) to creamy white (buffalo milk). The colour of milk is due to the combined effect of colloidal casein particles and the dispersed fat globules, both of which scatter light and carotene and to some extent xanthophylls, which impart a yellowish tint to milk. The intensity of yellow colour of cow milk is dependent upon factors such as breed, feed, size of fat globule present in milk, fat percentage. In buffalo milk, the carotene is present in the form of vitamin A. Skim milk has a bluish and whey a greenish yellow colour.
5. Can I make ice ream in my home with conventional refrigerator?
No. It is not possible to prepare ice cream in home with the conventional refrigerator. After the preparation of ice cream mix, it is frozen in the ice cream freezer (batch type or continuous) along with incorporation of air during the freezing process. This step is very essential to get proper body and texture in the finished product.
6. What is responsible for the characteristic flavour in curd?
Curd is a fermented dairy product produced by souring milk with mainly lactic starter cultures, which include Lactococcus lactis subspecies lactis, Lactococcus lactis subspecies cremoris and Lactococcus lactis subspecies lactis biovar diacetylactis. Sometimes, the starter may contain Leuconostocs. The Lactococcus lactis subspecies lactis, Lactococcus lactis subspecies cremoris are capable of fermenting lactose present in the milk into lactic acid resulting in coagulation of milk whereas the Lactococcus lactis subspecies lactis biovar diacetylactis is both lactose and citric acid fermenter. Citric acid fermentation results in the production of end products such as diacetyl, acetoin and 2,3 butylene glycol which are responsible for the characteristic desirable flavour production. Leuconostocs are purely citric acid fermenting bacteria and hence responsible for flavour production but not acid production.
7. What is the difference between Maillard browning and caramelization?
The darkening of colour commonly referred to as browning discolouration is a defect, which develops during the manufacture and storage of condensed milk varieties. The browning results from the interaction of amino compounds with sugar i.e. mainly casein with lactose. This defect is called as Maillard browning. Caramelization or non amino browning occurs in milk products due to heat decomposition of sugar in the absence of amino compounds.
8. What is meant by SNF and total solids?
SNF or solids not fat is that nutrient portion present in milk devoid of milk fat. It consists of protein and lactose. When SNF is combined with milk fat, then it is called total solids. The legal standards for standardized milk is 4.5% fat and 8.5% SNF and yes, as you rightly guessed, the total solids is 13%.
9. Human digestive system is not designed to digest cow milk. Is it right?
Humans are omnivorous. The alimentary canal of human beings is designed to digest plant as well as animal products such as meat and dairy products. Through evolution, humans acquired the capacity to synthesize an enzyme “lactase” or “beta galactosidase” that aids in digestion of lactose, the milk sugar. If the humankind is restricted to consuming milk from our own species, we would have missed many of the mouth watering, delicious dairy products that we enjoy today.
10. Does drinking milk cause kidney stone?
Calcium in milk will bind with the oxalates present in food so that they are made unavailable to be absorbed by the body. Hence, milk will in fact, help in reducing the chances of getting kidney stones and foster health of the consumers.