MILK
Milk can be defined as whitish liquid rich in nutrients produced by the mammary glands of female mammals for their young ones. It is considered as a wholesome natural food that comprises of all the nutrients that babies of the mammals require for their growth and health. Human beings rely on livestock milk as a source of protein and consume it almost daily. Different studies have been conducted to determine whether milk from livestock is more beneficial or harmful to our health. This study focuses on how the production and processing of milk influence its composition, nutrition quality, and health of the consumers and the measures that exist to minimize the hazards in milk.
Composition and Nutritional Quality of Milk
The composition of milk in livestock varies due to several factors, including the species, environment, feeding, breed, health, and lactation stage. The most common type of milk consumed by people across the globe is cow milk. Different components make up milk, and each has nutritional value. The highest part is water, which occupies up to approximately 87% of the milk, and the rest is total solids. Milk fat is formed at the top of milk, and its density varies in different species. It is made up of triacylglycerol, which are fatty acids, diacylglycerol, phospholipids, hydrocarbons, and sterols. It is useful in acting as a solvent in the body for the fat-soluble vitamins, namely A, D, E, K. Milk fats also provide essential fatty acids linoleic, linolenic, and arachidonic into the body.
Another component of milk is the proteins that play vital roles in reproduction and body structure. Milk protein is considered to be the main useful component that dairy contributes to the human body. Protein provides different types of amino acids to humans. It comes in various polymer forms, such as lipoproteins that contain fats, phosphoproteins, and chromo proteins, all of which are called conjugated proteins. Casein in milk is formed as a result of a combination of protein and phosphorous. It is easily separated from milk using acids or using rennin. Other than casein, there are other forms of protein in milk, including whey protein and enzymes.
Milk also has carbohydrates with lactose being the major one in the composition. Lactose is made from a combination of glucose and galactose sugars and is influenced by mastitis, which lowers its secretion. The lactose is a good source of energy despite being less soluble in water and having a lower sweet taste than other carbohydrates. Lactose is not eliminated in whey used for cheese making. When subjected to heat above 1000C, lactose combines with milk proteins, and the process is irreversible hence lowering the nutritive value of milk. Milk also contains some salts such as phosphates, chlorides, and citrates of calcium, sodium, and magnesium. Milk vitamins consist of A, D, E, and K, which are fat-soluble. A small portion of vitamin B complex and C, which are water-soluble, are also found.
Production of Milk
Milk is obtained from cows through the milking process. A cow is considered to be a living factory that takes in feeds and converts them to raw milk full of nutrients from the meal. The mode of feeding determines the amount and quality of milk to be produced. Dairy cows producing high amounts of milk require a higher level of management to maintain the production level. The type of feeds given to the animal can cause milk to lower its quality as some contain chemicals that give the milk a different taste and smell. Poor management can result in the cows developing mastitis. The milkman is supposed to maintain a high level of hygiene as milk is delicate and can get contaminated easily. Milking can be done by hands in low production and the use of milking machines for commercial production. After the milk is obtained from the animals, it can be cooked and consumed or taken for further processing to produce other products.
Processing of Milk
Milk is taken through different processing methods to produce various products. Pasteurization is the easiest method of increasing the shelf life of milk. Here, the milk is heated rapidly to 720C for a minimum of fifteen seconds before being quickly cooled to ensure that all the unsafe bacteria and other microbes present in the milk are destroyed. If the milk I heated beyond this temperature, other useful microbes in milk will be destroyed, and the milk will lose value. It is, therefore, necessary to maintain the recommended temperature. After the milk has been pasteurized, it can be packed in air-tight containers without adding any other preservatives and sold. It can also be used to make other products such as yogurts.
Homogenization is another processing method that involves putting milk under high pressure to pass through small nozzles. This is done to disperse milk fat to prevent the formation of cream at the top of the milk, and hence, the milk gains a stable taste and texture. Sometimes the cream is removed partially or entirely through centrifugal separation, which results in skimmed milk or milk with low-fat content. The solids obtained can be reintroduced back to the milk depending on the preference of the consumer so that more nutrients are present in the milk. Ultrafiltration of milk is doe to separate the milk protein and calcium complexes from the milk carbohydrates and water. The milk is subjected to a membrane sheath under pressure where only water and lactose pass through. Depending on the consumer, the amount of protein can be regulated in the milk.
Another method is reverse osmosis, which is a process that is similar to ultrafiltration but different in the fact that only water is allowed to pass through the membrane, and the rest of the milk solids are left as the end product. This process does not cause any changes to the flavor. Powdered milk is made through the removal of water in milk. In this method, no membranes are used. Instead, spray drying is used. The milk powder does not change in its nutritional value as only water is removed, and the rest of the components are left intact. All these processes are done to produce an end product that is suitable for the consumer.
Different products are made from the processing of milk, which results in value addition. Whole milk is a product of milk and does not require much treatment as it is only boiled and consumed without removing any constituent. Another product is fermented milk, which is made using stable microbes, and the most common in this section is the yogurt. Others include cheese, milk powder, butter and ghee, cream, evaporated milk, condensed milk, whey milk, and casein. All these are obtained after processing milk.
Importance of Milk
Milk is an excellent source of protein for people. Proteins are considered to be the building blocks of the body tissues and muscles. With milk, you get high amounts of protein to heal any torn tissues, and hence, you get healthy. From research by dieticians, milk has been proven to assist in the loss of weight. It is proven than people exercising to lose weight tend to shed off fat quickly and gain more muscles.
The composition of milk comprises elements that are useful in the body in many ways. Milk has fat-soluble vitamins that are vital in the body. It also has mineral salts such as calcium that is important in bone formation, and thus, osteoporosis is prevented. Milk is a versatile commodity that can be used in a variety of ways. It can be used in the baking industry, making smoothies, oatmeal, and soups. The consumer has a variety of options in the use of milk.
Milk Hazards
Most milk poisons do not originate from the milk or the animal but other external sources. These chemicals are toxic and can cause health risks if consumed. More people would get sick without regulation of the external causes of milk poisoning because of drinking poisonous milk. However, milk has also been found to have elements that are not good for human health. Some people have lactose intolerance in their bodies. When they consume milk that contains lactose, they are unable to digest it and fall sick. They develop diarrhea, bloating, nausea, and cramps and require medical attention. Milk lactose is one of the components that provide energy to the body and can be poisonous to some people.
High amounts of fat and cholesterol in milk are unsafe for human consumption. These elements have been associated with causing heart problems, primarily due to the formation of fat layers on the heart and thus minimizing its functionality. Despite having high amounts of calcium, milk protein is also dangerous to human health. From research, a high intake of proteins results in decalcification where calcium is removed from the bones in a condition called osteoporosis. This weakens the bones, and hence, the person can get bone fractures quickly. In another study, milk is associated with the development of cancers that are related to hormones. These cancers were found in the breasts, testes, and prostate. Scientists believe that during pregnancy, cows naturally produce hormones, which are responsible for increasing the vulnerability of a person developing any of these cancers.
The other toxins to human health are from chemical origins introduced into the body of the cow and end up in the milk glands where they mix with milk. The control of mastitis in dairy cattle entails veterinary infusion of the antibiotics directly into the mammary gland of the animal. When the animal is treated with the drugs, the milk becomes contaminated and is required to be disposed of appropriately as it is dangerous to human health when consumed. Some people do not follow the veterinary instructions and find it hard to keep eliminating the milk for the stated days as this impacts the earnings. Instead, they reduce the number of days and continue to milk and sell it while the antibiotics have not been cleared in the mammary glands. This is unethical as it poses a danger to people’s health.
Other drugs, either injected, sprayed, or given orally to the cow to control endoparasites, ectoparasites, and other illnesses, have a longer residual removal time from the body. Most of these drugs, especially those injected, end up in the blood circulatory system where they are transported to the mammary glands and sieved into the milk. This is why veterinarian advice on the disposal of the milk until the drugs are out of the system. Failure to adhere to the guidelines and you consume the milk, and the drug could end up in your body. Hence, you get drug poisoning as cattle drugs are not fit for human consumption. The antibiotics lower the milk quality and make it harmful to human health.
There are zoonotic diseases that are transmitted through milk to human beings. These diseases are mainly caused due to consumption of raw or milk that is not adequately cooked. Many bacteria can get into the mammary glands and mix with milk and include salmonella, streptococcus, campylobacter, brucella, and mycobacterium species. These organisms also infect humans, and hence proper care is needed when boiling milk as most are easily killed by heating. Tuberculosis also can be transmitted through milk to man and is common in goat milk. Milk has been considered by research as the right agent in the transmission of diseases as it creates a pleasant environment that harbors the microbes and is also widely consumed.
Pesticides, herbicides, and insecticides can be poorly stored or applied and contaminate animal feeds. These chemicals contain harmful elements, especially chlorinated compounds that are transferred into the milk once they are ingested by the dairy animal. The chemicals can kill the animal as well as people when they consume milk from such animals. The substances have a long residual effect before they are eliminated from the body of the animal altogether, and if the contamination in the feeds is not identified early enough, the damage caused could be high in the dairy sector. Farmers are always advised to keep these drugs far from the animal feeds to avoid contaminations.
Mycotoxin molds have been proven to produce metabolites toxic to human health when they are put under favorable conditions in milk. They are caused by feeding animals with feeds that have developed aflatoxin due to poor storage in damp conditions. When cereals are not appropriately dried and then stored with high amounts of water, aflatoxin chemicals are formed, and they are transferred into the cows’ milk when fed. Aflatoxin is very harmful to human health and causes severe sickness, and in some cases, deaths have been reported due to high consumption. These toxins are not affected by pasteurization, and hence, they can be found in packed pasteurized milk from animals that consumed them.
Minimization of milk Hazards
Lactose-intolerant people are advised to consume milk that has no lactose. If this is not available, lactose is destroyed by ultra-heating milk. Another solution that is recommended is through the use of plant-based milk, which does not contain lactose. Plant-based milk has also been proven to have low cholesterol and fat; hence, heart problems are minimized significantly. Minimizing protein content in milk will ensure that osteoporosis does not occur, and therefore, the bones will remain rigid and firm. However, research indicates that there is no difference observed when people consume a lot of milk and take in more calcium as they remain prone to fractures. Thus, the best solution is to substitute milk with other beverages that have less or no proteins.
The use of antibiotics is necessary for the treatment of diseases in the dairy sectors. Parasitic organisms also need to be controlled as they are of economic importance. To ensure that these drugs do not end in human bodies, farmers are supposed to observe the guidelines given by the veterinarian or the manufacturer so that the drug residues are eliminated from the body before consuming the milk. The farmers also should be taught on the importance of allowing the drug to be removed from the body, as this will help them adhere to the instructions. It is not easy for the farmers to take three or more days as they pour the milk and go into a loss, and hence, creating awareness would help.
Many people lack information about zoonotic diseases transmitted through milk. Some people consume raw or uncooked milk and risk getting these diseases. After milk starts to boils, studies indicate that it should be allowed to continue boiling for at least a minute so that all harmful microbes are killed. Proper drying of cereals ensures that they do not get aflatoxins, and hence, the animals that consume them will have fresh milk. Animal feeds should also be checked for molds so that if they are there, they are correctly disposed of to avoid contamination. Agricultural chemicals should also be well kept far from animal feeds to prevent contaminating them. They should be kept in a separate room that is properly locked.
Milk Quality Assurance and Policies
In America, several laws regulate the milk industry under the federal Pasteurized Milk Ordinance. This body guides milk programs organized in different states in ensuring that diseases resulting from milk are not spread in America. The majority of the states have adopted the guidelines of this body and implements them. Other states have developed their policy guidelines that are adhered to by the farmers in the dairy sector. The production, processing, packaging, and distribution of milk and its products have been standardized nationally by the PMO to ensure uniformity across the country. For milk produced and consumed within a State, the state government regulates it. However, if the milk is sold past its production boundary, the federal government regulates it.
Raw milk in America has its laws where the Food and Drug Administration prohibits its sale past the State. Any milk that is taken beyond the State boundary is required to be sterilized by the FDA. Some states allow consumers to purchase raw milk directly from the farmer while others prohibit this and only allow raw milk for animal consumption. The States determine the requirements that a farmer needs to meet so that he can be granted a license to sell raw milk. Each State differs from the other, but all must ensure that their requirements must be in line with the PMO and FDA guidelines. However, in animal feed production, PMO does not have the authority to dictate raw milk.
Conclusion
The production of milk starts from the farm, where the farmer must feed the dairy animals well to produce milk. Then, the animals are milked, and raw milk is obtained. The raw milk can be processed into various end products depending on the intended purpose. Milk is considered as a whole meal for the young ones. It comprises of all nutrients required in the body. Despite having numerous advantages, milk has some hazardous effects on human beings. Some people are not tolerant of lactose in milk and develop digestion problems. Milk is a good agent in transmitting zoonotic diseases, microbes, and chemicals to people, which poses a health risk to them. The PMO has provided guidelines to the American States so that milk regulations are observed. Milk is an internationally recognized beverage, and understanding its health risks and advantages are necessary.