Why does milk need to be pasteurized?
575131#33
Proponents of raw milk (in the U.S.) advance two basic arguments for unpasteurized milk. They state that pasteurization destroys or damages some of the milk's nutrients, and that while pasteurization may kill dangerous bacteria, it also kills off good bacteria that raw milk supporters have stated to have health benefits. The United States Food and Drug administration has stated that this is false, and that pasteurizing milk does not destroy any of its nutritive value.
Raw milk
10341263#7
Pasteurization is widely accepted to improve the safety of milk products by reducing the exposure to pathogens. Opponents of pasteurization argue that unpasteurized milk has benefits associated with superior taste, nutritional qualities and certain health benefits over pasteurized milk. While pasteurization of milk kills off bacterial pathogens, other bacteria species with possible health benefits are also destroyed. Pasteurization of cow's milk destroys any potential pathogens and increases the shelf life. During pasteurization, however, these lactic acid bacteria are mostly destroyed. A 2009 systematic review of the food safety of unpasteurized milk concluded that science-based data to substantiate claims of health benefits "are lacking or do not exist" and the risks associated with disease outbreaks as a result of raw milk consumption are "considerably higher".
United States raw milk debate
23311#10
Developed countries adopted milk pasteurization to prevent such disease and loss of life, and as a result milk is now considered a safer food. A traditional form of pasteurization by scalding and straining of cream to increase the keeping qualities of butter was practiced in Great Britain in the 18th century and was introduced to Boston in the British Colonies by 1773, although it was not widely practiced in the United States for the next 20 years. Pasteurization of milk was suggested by Franz von Soxhlet in 1886. In the early 20th century, Milton Joseph Rosenau established the standards – i.e. low-temperature, slow heating at for 20 minutes – for the pasteurization of milk while at the United States Marine Hospital Service, notably in his publication of "The Milk Question" (1912). States in the U.S. soon began enacting mandatory dairy pasteurization laws, with the first in 1947, and in 1973 the U.S. federal government required pasteurization of milk used in any interstate commerce.
Pasteurization
10341263#6
Pasteurization is a sanitation process in which milk is heated briefly to a temperature high enough to kill pathogens, followed by rapid cooling. While different times and temperatures may be used by different processors, pasteurization is most commonly achieved with heating to 161 degrees Fahrenheit (71.7 degrees Celsius) for 15 seconds. Milk is tested following pasteurization to confirm that bacteria have been killed to an acceptable level. Pasteurization kills pathogenic bacteria which occasionally may be present in milk, including those causing tuberculosis ("Mycobacterium bovis"), listeriosis ("Listeria monocytogenes"), Q fever ("Coxiella burnetii"), brucellosis ("Brucella"), campylobacteriosis ("Campylobacter"), salmonellosis ("Salmonella"), and several other foodborne illnesses (e.g., ). Pasteurization may not kill some resistant bacteria, which can eventually cause souring and spoilage of fresh milk. UHT pasteurization (Ultra High Temperature) is a more extreme form of pasteurization heating milk to a temperature high enough to kill spoilage organisms also.
United States raw milk debate
23311#28
According to a systematic review and meta-analysis, it was found that pasteurization appeared to reduce concentrations of vitamins B12 and E, but it also increased concentrations of vitamin A. Apart from meta-analysis, it is not possible to draw conclusions about the effect of pasteurization on vitamins A, B12, and E based merely on consultation of the vast literature available. Milk is not an important source of vitamins B12 or E in the North American diet, so the effects of pasteurization on the adult daily intake of these vitamins is negligible. However, milk is considered an important source of vitamin A, and because pasteurization appears to increase vitamin A concentrations in milk, the effect of milk heat treatment on this vitamin is a not a major public health concern. Results of meta-analyses reveal that pasteurization of milk leads to a significant decrease in vitamin C and folate, but milk is also not an important source of these vitamins. A significant decrease in vitamin B2 concentrations was found after pasteurization. Vitamin B2 is typically found in bovine milk at concentrations of 1.83 mg/liter. Because the recommended daily intake for adults is 1.1 mg/day, milk consumption greatly contributes to the recommended daily intake of this vitamin. With the exception of B2, pasteurization does not appear to be a concern in diminishing the nutritive value of milk because milk is often not a primary source of these studied vitamins in the North American diet.
Pasteurization
575131#32
Many governmental officials and the majority of public health organizations hold to the need for pasteurization. Before pasteurization, many dairies, especially in cities, fed their cattle on low-quality food, and their milk was rife with dangerous bacteria. Pasteurizing it was the only way to make it safely drinkable. As pasteurization has been standard for many years, it is now widely assumed that raw milk is dangerous. The Cornell University Food Science Department has compiled data indicating that pathogenic microorganisms are present in between 0.87% and 12.6% of raw milk samples.
Raw milk
34629436#4
Deliveries of dairy products started at midnight. The dairy bought milk from local farmers and in order to deliver it the milk had to be tested, clarified, pasteurized and bottled. The two main reasons the milk was processed was to destroy human pathogens through pasteurization and to maintain product quality. Pasteurization was not required so not all dairies did it because of the added expense. The dairy needed to maintain strict cleanliness of the facility. Newens advertised, “Pasteurized Milk and Cream, Buttermilk and Cottage Cheese" and "You are invited to inspect our plant at any time. We pride ourselves on our cleanliness.”
Newens Sanitary Dairy Historic District
515468#10
The U.S. Food and Drug Administration does not maintain a standard of identity for "pasteurized prepared cheese product," a designation which particularly appears on many Kraft products. Nor does the FDA maintain a standard of identity for "pasteurized process cheese product" (emphasis on the trailing "Product"), a designation which appears particularly on many American store- and generic-branded singles. Products labeled as such may use milk protein concentrate (MPC) in the formulation, an ingredient which does not appear in the above FDA definitions. The desire to use inexpensive imported milk protein concentrate is noted as motivation for the introduction of these and similar terms, and for the relabeling of some products. After an FDA Warning Letter protesting Kraft's use of MPC in late 2002, some varieties of Kraft Singles formerly labeled "pasteurized process cheese food" became "pasteurized prepared cheese product," Velveeta was relabeled from "pasteurized process cheese spread" to "pasteurized prepared cheese product," and Easy Cheese from "pasteurized process cheese spread" to "pasteurized cheese snack."
Processed cheese
19714#49
Microfiltration is a process that partially replaces pasteurization and produces milk with fewer microorganisms and longer shelf life without a change in the taste of the milk. In this process, cream is separated from the skimmed milk and is pasteurized in the usual way, but the skimmed milk is forced through ceramic microfilters that trap 99.9% of microorganisms in the milk (as compared to 99.999% killing of microorganisms in standard HTST pasteurization). The skimmed milk then is recombined with the pasteurized cream to reconstitute the original milk composition.
Milk
4997719#7
Milk banks require freezers and pasteurizers for processing milk. Most milk banks have two freezers, for unprocessed and processed milk. The HMBANA guidelines state that "all milk should be heat treated for 30 minutes at 62.5 °C. Heat treatment of milk occurs at 62.5°C for 30 minutes (Holder pasteurizing)" (Arnold, 1997, p. 243). At the end of pasteurization, another sample of milk is tested to make sure the treatment was effective. Colony counts should be zero and no bacterial growth should be detected (Arnold, 1997). Containers for pasteurizing must be able to withstand heating and cooling without breakage or leaking. Most containers are recyclable, usually glass or plastic.
Human milk banking in North America