Food Safety Hazards Associated with Consumption of Raw Milk

Department of Animal Science, The University of Tennessee, Knoxville, Tennessee 37996, USA.
Foodborne Pathogens and Disease (Impact Factor: 1.91). 10/2009; 6(7):793-806. DOI: 10.1089/fpd.2009.0302
Source: PubMed


An increasing number of people are consuming raw unpasteurized milk. Enhanced nutritional qualities, taste, and health benefits have all been advocated as reasons for increased interest in raw milk consumption. However, science-based data to substantiate these claims are limited. People continue to consume raw milk even though numerous epidemiological studies have shown clearly that raw milk can be contaminated by a variety of pathogens, some of which are associated with human illness and disease. Several documented milkborne disease outbreaks occurred from 2000-2008 and were traced back to consumption of raw unpasteurized milk. Numerous people were found to have infections, some were hospitalized, and a few died. In the majority of these outbreaks, the organism associated with the milkborne outbreak was isolated from the implicated product(s) or from subsequent products made at the suspected dairy or source. In contrast, fewer milkborne disease outbreaks were associated with consumption of pasteurized milk during this same time period. Twenty nine states allow the sale of raw milk by some means. Direct purchase, cow-share or leasing programs, and the sale of raw milk as pet food have been used as means for consumers to obtain raw milk. Where raw milk is offered for sale, strategies to reduce risks associated with raw milk and products made from raw milk are needed. Developing uniform regulations including microbial standards for raw milk to be sold for human consumption, labeling of raw milk, improving sanitation during milking, and enhancing and targeting educational efforts are potential approaches to this issue. Development of pre- and postharvest control measures to effectively reduce contamination is critical to the control of pathogens in raw milk. One sure way to prevent raw milk-associated foodborne illness is for consumers to refrain from drinking raw milk and from consuming dairy products manufactured using raw milk.

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    • "Unless a large number of STEC (that have produced a substantial amount of Stx(s)) are present in the raw milk before pasteurization, eliminating STEC by pasteurization should be sufficient to ensure safe milk. There will always be the threat of contamination of milk during the production process whether it be during raw milk production or after pasteurized milk has been heat treated (Oliver et al., 2009). Although heat treatment is still the best strategy to eliminate pathogens in milk, options for raw milk are much more limited. "
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    ABSTRACT: Commensal Escherichia coli are commonly utilized for investigating the genetic and biochemical requirements of microorganisms, and have served in a wide variety of applications. Pathogenic E. coli known as Shiga toxin (Stx)-producing E. coli (STEC) are associated with various food products including ground beef. These pathogens are present in a wide range of environments, and have caused numerous foodborne outbreaks and recalls. These outbreaks and the increased awareness of STEC have led to certain STEC serotypes to be declared adulterants in non-intact raw meat. Various STEC detection methods have been investigated, and numerous cultural and molecular-based detection methods continue to be modified to meet regulatory requirements. However, STEC serotypes may possess certain characteristics that lead to bias in the likelihood of a certain serotype being detected in an assay. Understanding the characteristics of these STEC serotypes will provide means for optimizing the detection platforms, and as a result limit foodborne illness and recalls caused by STEC due to enhanced cultural and molecular detection capabilities.
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    • "Owing to the mild taste, convenience, low cost, and high nutritional quality, popularity of raw milk is growing among adults (Kaylegian et al., 2008); however, the rising trend of raw milk consumption has been accompanied by food poisoning outbreaks (Oliver et al., 2009). In Europe and the United States, thermophilic Campylobacter spp., shigatoxic Escherichia coli, Salmonella spp., and Staphylococcus aureus are the 4 main pathogenic bacteria frequently associated with milkborne outbreaks (Ruusunen et al., 2013). "
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    ABSTRACT: The Pacific Biosciences (Menlo Park, CA) single molecule, real-time sequencing technology (SMRT) was reported to have some advantages in analyzing the bacterial profile of environmental samples. In this study, the presence of bacterial contaminants in raw milk, UHT milk, and infant formula was determined by SMRT sequencing of the full length 16S rRNA gene. The bacterial profiles obtained at different taxonomic levels revealed clear differences in bacterial community structure across the 16 analyzed dairy samples. No indicative pathogenic bacteria were found in any of these tested samples. However, some of the detected bacterial species (e.g., Bacillus cereus, Enterococcus casseliflavus, and Enterococcus gallinarum) might potentially relate with product quality defects and bacterial antibiotic gene transfer. Although only a limited number of dairy samples were analyzed here, our data have demonstrated for the first time the feasibility of using the SMRT sequencing platform in detecting bacterial contamination. Our paper also provides interesting reference information for future development of new precautionary strategies for controlling the dairy safety in large-scale industrialized production lines.
    Full-text · Article · Oct 2015 · Journal of Dairy Science
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    • "Amongst pathogens that are a danger to human health when orally digested are Salmonella, Staphylococcus and Listeria, each of which is a major public health problem and each of which is killed by high temperature cooking. Salmonella poisoning is most commonly the result of poor storage and inadequate cooking of meats, notably chicken (Juneja et al. 2007), and Listeriosis is a hazard usually associated with consumption of raw milk, although contamination of meat and other foods occurs (Oliver et al. 2009). "
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    ABSTRACT: We discuss the relations of processed foods, especially cooked foods, in the human diet to digestive tract form and function. The modern consumption of over 70 % of foods and beverages in highly refined form favours the diet-related classification of humans as cucinivores, rather than omnivores. Archaeological evidence indicates that humans have consumed cooked food for at least 300–400,000 years, and divergence in genes associated with human subpopulations that utilise different foods has been shown to occur over periods of 10–30,000 years. One such divergence is the greater presence of adult lactase persistence in communities that have consumed dairy products, over periods of about 8,000 years, compared to communities not consuming dairy products. We postulate that 300–400,000 years, or 10,000–14,000 generations, is sufficient time for food processing to have influenced the form and function of the human digestive tract. It is difficult to determine how long humans have prepared foods in other ways, such as pounding, grinding, drying or fermenting, but this appears to be for at least 20,000 years, which has been sufficient time to influence gene expression for digestive enzymes. Cooking and food processing expands the range of food that can be eaten, extends food availability into lean times and enhances digestibility. Cooking also detoxifies food to some extent, destroys infective agents, decreases eating time and slightly increases the efficiency of assimilation of energy substrates. On the other hand, cooking can destroy some nutrients and produce toxic products. The human digestive system is suited to a processed food diet because of its smaller volume, notably smaller colonic volume, relative to the intestines of other species, and because of differences from other primates in dentition and facial muscles that result in lower bite strength. There is no known group of humans which does not consume cooked foods, and the modern diet is dominated by processed foods. We conclude that humans are well adapted as consumers of processed, including cooked, foods.
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