Instruct: Given a question, retrieve relevant documents that can help answer the question.
Query: Why does milk need to be pasteurized?
Pasteurization or pasteurisation is a process in which certain packaged and non-packaged foods (such as milk and fruit juice) are treated with mild heat, usually less than 100°C (212°F), to eliminate pathogens and extend shelf life. The process is intended to sterilize foods by destroying or inactivating organisms that contribute to spoilage, including vegetative bacteria but not bacterial spores.[1][2]
In 2002, the FDA issued a Warning Letter to Kraft Foods that Velveeta was being sold with packaging that described it as a "Pasteurized Process Cheese Spread", which the FDA claimed was misbranded because the product declared milk protein concentrate (MPC) in its ingredients listing. Velveeta is now sold in the US as a "Pasteurized Prepared Cheese Product", a term for which the FDA does not maintain a standard of identity, and which therefore may contain MPC.
In milk, the color difference between pasteurized and raw milk is related to the homogenization step that takes place prior to pasteurization. Before pasteurization, milk is homogenized to separate the solids (fat) from the liquid, which results in the pasteurized milk having a whiter appearance compared to raw milk.[1] For vegetable products, color degradation is dependent on the temperature conditions and the duration of heating.[53]
Pasteurization is the process of heating milk to a high enough temperature for a short period of time to kill the microbes in the milk and increase keep time and decrease spoilage time. By killing the microbes, decrease the transmission of infection, and elimination of enzymes the quality of the milk and the shelf life increases. Pasteurization is either completed at 63 °C for thirty minutes or a flash pasteurization is completed for 15 seconds at 72 °C. By-products of milk include butterfat, cream, curds, and whey. Butterfat is the main lipid in milk. The cream contains 18–40% butterfat. The industry can be divided into 2 market territories; fluid milk and industrialized milk such as yogurt, cheeses, and ice cream. 
Steam infusion can be used to pasteurize a variety of dairy products. For ultra pasteurization, also known as ultrahigh-temperature (UHT) pasteurization, the milk is heated to temperatures in the order of 140 °C. During steam infusion, milk is brought into contact with steam at 140 °C for one or two seconds. The heating is instantaneous, and the milk is cooled rapidly by evaporative cooling exposure to a slight vacuum, removing any water added to the milk by condensation of the steam.
Advocates of drinking raw milk claim raw milk contains desirable substances, such as enzymes, that cannot survive the heating process and may be destroyed during pasteurization; specifically, immunoglobulins and the enzymes lipase and phosphatase, which are inactivated by heat, are believed to be beneficial. In contrast, food scientists and FDA officials assert that most "beneficial" enzymes survive pasteurization; that those few enzymes that are present in raw milk and denatured in pasteurized milk are ultimately degraded in the low pH environment of the stomach anyway; and that the enzymes present in milk are not used by humans to metabolize nutrients.
The amount and variety of dairy products of Alpura have grown through the years. When Alpura introduced ultra-pasteurized milk, it changed the Mexican market. Before there was not a business plan to sell milk in Mexico and therefore there were no companies who sold milk. Also in the past the milk didn't have a specific production process. With the ultra-pasteurization, all the bacteria are killed and the milk is made with a careful process. Today, Alpura has five different dairy products with numerous brands under each type of product: milk, cream, yogurt, drinkable yogurt and dessert cups.
Milk can be Classic, Semi, and Light in Pasteurized and Ultra Pasteurized, Special (ex. Extra Light, W/out Lactose, No Cholesterol), Alpura Fruit (in ultra-pasteurized and to-go), Dry milk, flavors (such as chocolate, vanilla and strawberry), Alpura Kids, and formula milk. Cream 2000, and Reduced Fat.
Yogurt is: Probiotic in Strawberry or Peach, With Fruits (strawberry, peach, apple, mango, forest fruit, pineapple coconut, and blackberry), Natural, Creamy, Vivendi (beauty, purifying, digestion, defenses), With Cereal (strawberry, peach, apple-peach, forest fruit)
The Drinkable Yogurt is of most of the same flavors as regular yogurt in Regular, Probiotic, and Vivendi.
Dessert cups are Fruit w/ Cream (strawberry, peach, mango).
Pasteurization is credited with dramatically reducing pathogens found in milk. This improves the shelf-life and safety of the processed milk. Advocates of drinking raw milk claim various health benefits they attribute to raw milk that are lost in the pasteurization process, and claim that raw milk can be produced as hygienically as pasteurized milk. Raw milk advocates may go as far as to claim that untreated milk is a "miracle cure" for illnesses such as asthma or gastrointestinal disorders. A 2006 systematic review of infections associated with raw milk contends that pasteurized milk is substantially safer than raw milk, and comparably nutritious to raw milk, therefore there is no scientific reason for choosing raw milk products. Similarly, a recent review authored by the Belgian Federal Agency for the Safety of the Food Chain and experts from Belgian universities and institutions concluded that "raw milk poses a realistic health threat due to a possible contamination with human pathogens. It is therefore strongly recommended that milk should be heated before consumption. With the exception of an altered organoleptic [flavor] profile, heating (in particularly ultra high temperature and similar treatments) will not substantially change the nutritional value of raw milk or other benefits associated with raw milk consumption."
A less aggressive method was developed by French chemist Louis Pasteur during an 1864[13] summer holiday in Arbois. To remedy the frequent acidity of the local aged wines, he found out experimentally that it is sufficient to heat a young wine to only about 50–60°C (122–140°F) for a short time to kill the microbes, and that the wine could subsequently be aged without sacrificing the final quality.[13] In honour of Pasteur, this process became known as "pasteurization".[2][14] Pasteurization was originally used as a way of preventing wine and beer from souring,[15] and it would be many years before milk was pasteurized. In the United States in the 1870s, it was common for milk to contain substances intended to mask spoilage before milk was regulated.[16]
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."
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[86] (as compared to 99.999% killing of microorganisms in standard HTST pasteurization).[87] The skimmed milk then is recombined with the pasteurized cream to reconstitute the original milk composition.
Proponents also invoke the benefits of direct-marketing when promoting the sale of raw milk. The ability of the farmer to eliminate the middle-man and sell directly to the consumer allows for greater profitability. Many manufacturers sell small-scale pasteurization equipment, thereby allowing farmers to both bypass the milk processors and sell pasteurized milk directly to the consumer. Additionally, some small U.S. dairies are now beginning to adopt low-temperature vat pasteurization. Advocates of low-temperature vat pasteurization note that it produces a product similar to raw milk in composition.
Pasteur's research also showed that the growth of micro-organisms was responsible for spoiling beverages, such as beer, wine and milk. With this established, he invented a process in which liquids such as milk were heated to a temperature between 60 and 100 °C. This killed most bacteria and moulds already present within them. Pasteur and Claude Bernard completed tests on blood and urine on April 20, 1862. Pasteur patented the process, to fight the "diseases" of wine, in 1865. The method became known as pasteurization, and was soon applied to beer and milk.
The shelf life of refrigerated pasteurized milk is greater than that of raw milk. For example, high-temperature, short-time (HTST) pasteurized milk typically has a refrigerated shelf life of two to three weeks, whereas ultra-pasteurized milk can last much longer, sometimes two to three months. When ultra-heat treatment (UHT) is combined with sterile handling and container technology (such as aseptic packaging), it can even be stored non-refrigerated for up to 9 months.[34]
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.”
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.
Chal may be cultured with lactobacillus casei, streptococcus thermophilus and lactose-fermenting yeasts incubating in inoculated milk for 8 hours at 25 °C (77 °F), and then subsequently for 16 hours at 20 °C (68 °F). Holder pasteurization does not affect the quality of the milk, but pasteurization at higher temperatures ( 85 °C/185 °F) for 5 minutes negatively impacts flavour. Chal made from pure cultures of lactobacillus casei, streptococcus thermophilus and species of torula has markedly less not-fat solids and lactose than the milk from which it is made.
Pasteurization does lead to decreased levels of several vitamins, but only approximately 0–10%. Research shows only very slight differences in the nutritional values of pasteurized and unpasteurized milk. Raw milk contains very little vitamin D, which is added to processed milk.
At-Tahur markets its range of dairy products under the brand name of Premá. These include pasteurized milk, yogurt, chocolate milk, raita and milk smoothies. The flagship product of the company is pasteurized milk, which accounts for 72% of its sales, and is the segment in which the company retains market dominance. Pasteurized milk is followed by yogurt variants, which combine to give 20% of the company's sales.
The U.S. Centers for Disease Control and Food and Drug Administration disagree with this, noting that the pasteurization process "does not significantly change the nutritional value of milk" and that consumption of raw milk poses a "severe health risk". They point out that prior to the widespread use of pasteurization, many diseases were commonly transmitted by raw milk, while by 2005 they made up less than 1% of food and water contamination disease outbreaks.. The director of the U.S. Food and Drug Administration Division of Plant- and Dairy-Food Safety, John Sheehan, called the organization's claims on the health benefits and safety of raw milk "false, devoid of scientific support, and misleading to consumers"
In 2002, the FDA issued a warning letter to Kraft that Velveeta was being sold with packaging that described it as a "Pasteurized Process Cheese Spread", which the FDA claimed was false because the product listed milk protein concentrate (MPC) in its ingredients. Velveeta is now sold in the US as a "Pasteurized Prepared Cheese Product", a term for which the FDA does not maintain a standard of identity, and which therefore may contain milk protein concentrate.
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.
According to a systematic review and meta-analysis,[48] 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.[48] 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.[49][50] However, milk is considered an important source of vitamin A,[51] 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.[48] 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.[51][50] A significant decrease in vitamin B2 concentrations was found after pasteurization. Vitamin B2 is typically found in bovine milk at concentrations of 1.83mg/liter. Because the recommended daily intake for adults is 1.1mg/day,[52] 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.
The Codex Alimentarius Code of Hygienic Practice for Milk notes that milk pasteurization is designed to achieve at least a 5 log10 reduction of Coxiella burnetii.[46] The Code also notes that: “The minimum pasteurization conditions are those having bactericidal effects equivalent to heating every particle of the milk to 72°C for 15 seconds (continuous flow pasteurization) or 63°C for 30 minutes (batch pasteurization)” and that “To ensure that each particle is sufficiently heated, the milk flow in heat exchangers should be turbulent, i.e. the Reynolds number should be sufficiently high.” The point about turbulent flow is important because simplistic laboratory studies of heat inactivation that use test tubes, without flow, will have less bacterial inactivation than larger-scale experiments that seek to replicate conditions of commercial pasteurization.[47]
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".