Campylobacteriosis is the leading bacterial gastrointestinal disease internationally, contributing significantly to the enteric illness burden. Cases have been associated with the consumption of raw milk, a behavior that has garnered attention recently. Estimates of the prevalence and levels of Campylobacter spp. in raw milk are lacking, which hinders risk assessment attempts. This article is a systematic review and meta-analysis of reported prevalence and levels of zoonotic Campylobacter spp. in the raw milk of cows, goats, and sheep in Canada, the United States, Europe, Australia, and New Zealand. The relevant literature was reviewed, and trained reviewers examined the results for inclusion of articles in the meta-analysis. Relevant data (prevalence and/or level of Campylobacter in raw milk, country of origin, animal species, sample source, Campylobacter species identified, etc.) were extracted, and a meta-analysis was performed in Stata v. 12 (Metaprop command). The weighted mean prevalence of Campylobacter spp. in raw milk samples was 1.18%. Subgroup analyses were conducted to examine how prevalence varied by study characteristics, with the highest prevalence values in studies from the United Kingdom (by country, 6.4%), about cows (by animal species, 1.3%), and including samples taken from inline filters (by sample source, 1.75%) and in studies that included species that are not pathogenic to humans (by Campylobacter species, 1.14%). Two articles each included a single Campylobacter level, 0.16 ± 0.3 and approximately 0.047 most probable number per ml. Despite a relatively low prevalence, consumption of raw milk is inherently risky because no treatment has been used to inactivate pathogens. This potential risk further supports maintaining regulations to limit the sales of raw milk.

Reviewing “zoonotic diseases” classically brings to mind human infections contracted in close association with animals, where outdoor occupations and afforested lands usually play a key role in the epidemiological triad. However, there is a very common, yet overlooked route of infection where humans may not come in direct contact with animals or implicated environments. Milk-borne diseases are a unique set of infections affecting all age groups and occupational categories of humans, causing 4% of all the foodborne diseases in the world. The infection reservoir may lie with milch animals and associated enzootic cycles, and the infectious agent is freely secreted into the animal’s milk. Commercial pooling and processing of milk create unique environmental challenges, where lapses in quality control could introduce infective agents during downstream processing and distribution. The infectious agent is finally brought to the doorstep of both rural and urban households through such animal products. The domestic hygiene of the household finally determines human infections. One health approach can target preventive measures like immunization in animals, pasteurization and stringent quality control during the commercial processing of milk, and finally, hygienic practices at the level of the consumer, to reduce the burden of milk-borne diseases. This review hopes to draw the attention of policymakers to this unique route of infection, because it can be easily regulated with cost-effective interventions, to ensure the safety of this precious food product, permeating the life and livelihood of humans from all walks of life. The infectious agent is finally brought to the doorstep of both rural and urban households through such animal products. The domestic hygiene of the household finally determines human infections. One health approach can target preventive measures like immunization in animals, pasteurization and stringent quality control during the commercial processing of milk, and finally, hygienic practices at the level of the consumer, to reduce the burden of milk-borne diseases. coli O157:H7 >20 Jones et al., 2019 2019 France STEC 026 16 Gruber et al., 2021 2019 Pennsylvania, USA Yersinia enterocolitica 109 Wang et al., 2020 2019 Guangdong, China Brucella melitensis 30 Understanding the epidemiological triad–Agent, host, and environment The microbiota of raw milk can be divided into three main categories- beneficial flora, spoilage flora, and pathogens. The beneficial flora of the milk includes Lactococcus , Lactobacillus , and Leuconostoc species. Spoilage organisms are the psychrotrophic organisms that flourish in milk even at low temperatures and cause degradation of milk components viz. Pseudomonas, Acinetobacter, Serratia , and Aeromonas. FIGURE 1 Steps of milk processing and list of pathogens that can enter milk at various stages of processing. Raw milk causes 840 times more illnesses and 45 times the hospitalizations caused by pasteurized milk ( Costard et al., 2017 ). Taking developing countries into account, Mycobacterium bovis , one of the causal agents of human tuberculosis, is found in about 10–15% of the cases in developing countries ( Ashford et al., 2001 ). It can remain viable in cheese and yogurt made from raw milk for up to 14 days and up to 100 days in butter making it highly transmissible ( de la Rua-Domenech, 2006 ). World Health Organization estimates that M. bovis alone may have caused 143,000 new cases and 12,300 deaths in 2018 ( Chakaya et al., 2022 ). Milk borne diseases would be incomplete without a mention of Brucella species. There is a lack of reliable data on the global burden of brucellosis. However, around 5,000,000 cases of Brucellosis are expected to occur each year which is very likely to be an understatement ( Jamir et al., 2020 ). Another notorious pathogen is Campylobacter spp. which makes its way into the milk due to fecal contamination from infected organisms. Several cases of Campylobacter infection due to raw milk have been found in both developing and developed countries ( Christidis et al., 2016 ). Another notable fact is that a relatively younger set of the population is at a greater risk of acquiring infections due to raw milk consumption ( Robinson et al., 2014 ). It can be attributed to a common myth that pasteurization alters the milk quality and decreases its nutritional value. This erroneous interpretation of pasteurization procedures by the masses has led to perilous consequences including hospitalization due to severe disease and even death ( Costard et al., 2017 ). Human milk can serve as a conduit for several infections such as Q fever, Creutzfeldt- Jakob disease, etc. The origin of disease transmission via human milk banks begins with improper donor selection. As human milk is formed from blood, the donors are screened for all blood-borne pathogens. After screening and informed consent, the donor has to be counseled and instructed on the proper method of collection. After this, microbiological screening of milk should be done once before pasteurization and once after. Screening of organisms such as S. aureus and E. coli is done and the batch for which colony count exceeds 10 5 CFU/ml is discarded. Education must be given to dairy farmers to look for early signs and symptoms of diseases in the animals ( Table 1 ) and the availability of the nearest veterinary services to get the animals treated. Specific protection It is easy to understand that outbreaks due to raw milk are caused by pathogens that have animal reservoirs. Mandatory record keeping of vaccination status and health checkups of animals by dairy farmers is indispensable. Immunization of milch animals goes a long way in assuring the wellbeing of the animals. Firstly, it leads to the development of antibodies in the animal at levels enough to prevent the invasion of organisms in mammary glands.

Goat milk is an interesting product from a nutritional and health standpoint, although its physico-chemical composition presents some technological challenges, mainly for being less stable than cow’s milk at high temperatures. As pasteurization and ultra-high temperature processing are universally employed to ensure milk quality and safety, non-thermal methods, such as pulsed electric fields (PEFs), reduce the microbial load and eliminate pathogens, representing an interesting alternative for processing this product. This study demonstrates how the combined use of a PEF with short thermal processing and moderate temperature can be effective and energy-efficient in goat milk processing. A combination of thermal treatment at 63 °C after a low-intensity PEF (50 µs pulses, 3 Hz, and 10 kV·cm−1) caused the same reduction effect on the population of Listeria monocytogenes (goat’s raw milk artificially spiked), as compared to a thermal treatment at 72 °C without a PEF. However, z values are significantly higher when PEF is used as a pre-treatment, suggesting that it may induce heat resistance in the survival population of L. monocytogenes. The sensitivity of L. monocytogenes to high temperatures is less pronounced in goat’s milk than cow’s milk, with a more pronounced impact of a PEF on lethality when combined with lower temperatures in goat’s milk. The effect of a PEF on Escherichia coli viability was even more pronounced. It was also observed that thermal treatment energy needs with a PEF as a pre-treatment can be reduced by at least 50% of the total energy requirements.

Raw milk or unpasteurized milk is milk that has not undergone pasteurization, a process of heating liquid foods to kill pathogens for safe consumption Raw milk or unpasteurized milk is milk that has not undergone pasteurization, a process of heating liquid foods to kill pathogens for safe consumption and extension of shelf life. Proponents of raw milk have alleged numerous purported benefits to consumption, including better flavor, better nutrition, contributions to the building of a healthy immune system and protection from allergies. However, In the… Raw milk or unpasteurized milk is milk that has not undergone pasteurization, a process of heating liquid foods to kill pathogens for safe consumption and extension of shelf life. Proponents of raw milk have alleged numerous purported benefits to consumption, including better flavor, better nutrition, contributions to the building of a healthy immune system and protection from allergies. However, no clear benefit to consumption has been found. In contrast, a broad consensus in the medical community warns there is an Humans first regularly consumed the milk of other mammals following the domestication of animals during the Neolithic Revolution or the development of agriculture. This development occurred independently in several places around the world from as early as 9000–7000 BC in Mesopotamia to 3500–3000 BC in the Americas. The most important dairy animals—cattle, sheep and goats—were first domesticated in Mesopotamia, although domestic cattle have been independently derived from wild aurochs populations several times since. From there, dairy animals spread to Europe (beginning around 7000 BC but not reaching Britain and Scandinavia until after 4000 BC), and South Asia (7000–5500 BC). Pasteurization is widely used to prevent infected milk from entering the food supply. The pasteurization process was developed in 1864 by French scientist Louis Pasteur, who discovered that heating beer and wine was enough to kill most of the bacteria that caused spoilage, preventing these beverages from turning sour. The process achieves this by eliminating pathogenic microbes and lowering microbial numbers to improve shelf life. After sufficient scientific study led to the development of germ theory, pasteurization was introduced in the United States in the 1890s. This move successfully controlled the spread of highly contagious bacterial diseases, including E. coli, bovine tuberculosis, and brucellosis (all thought to be easily transmitted to humans through the drinking of raw milk). In the early days after the scientific discovery of bacteria, there was no product testing to determine whether a farmer's milk was safe or infected, so all milk was treated as potentially contagious. After the first tests were developed, some farmers took steps to prevent their infected animals from being killed and removed from food production, sometimes even falsifying test results to make their animals appear free of infection. Recent advances in the analysis of milk-borne diseases have enabled scientists to track the DNA of the infectious bacteria to the cows on the farms that supplied the raw milk. The recognition of many potentially deadly pathogens, such as E. coli 0157 H7, Campylobacter, Listeria, and Salmonella, and their possible presence in poorly produced milk products has led to the continuation of pasteurization. The U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, and other health agencies of the United States strongly recommend that the public not consume raw milk or raw milk products. Young children, the elderly, people with weakened immune systems, and pregnant women are more susceptible to infections originating in raw milk. In the early 20th century, many states within the United States allowed the sale of raw milk that was certified by a "medical milk commission", effectively allowing an alternative of extra inspection for pasteurization. Most states impose restrictions on raw milk suppliers due to safety concerns. 43 U.S. states allow the sale of raw milk. Cow shares can be found, and raw milk purchased for animal consumption in many states where retail for human consumption is prohibited. The sale of raw milk cheese is permitted if the cheese has been aged for at least 60 days. In 1987, the U.S. Food and Drug Administration (FDA) banned the sale of raw milk intended for human consumption across state borders. The FDA reported that, in 2002, consuming partially heated raw milk and raw milk products caused 200 Americans to fall ill. Most public health organizations, including the CDC, hold to the need for pasteurization. Before pasteurization, many dairies, especially in cities, fed their cattle on low-quality feed, producing milk rife with dangerous bacteria. Pasteurizing it was the only way to make it safely drinkable. 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. Proponents also invoke the benefits of direct marketing when promoting the sale of raw milk. The farmer's ability to eliminate intermediaries and sell directly to the consumer. This allows for greater profitability. Many manufacturers sell small-scale pasteurization equipment, allowing farmers to bypass the milk processors and sell pasteurized milk directly to consumers. Additionally, some small U.S. dairies are now adopting low-temperature vat pasteurization. Advocates of low-temperature vat pasteurization note that it produces a product similar to raw milk in composition. Food freedom advocates cite libertarian arguments and claim a basic civil right each person has to weigh the risks and benefits of choosing the food one eats, including the choice to consume raw milk.. The American Health Secretary Robert F. Kennedy Jr, who is serving in the Donald Trump administration, is also a supporter of raw milk consumption.

A role for milk phospholipids in protection against gastric acid. Studies in adult and suckling rats. Animal milk was tested directly for antiulcer activity in a rat model system. The severe mucosal necrosis and intragastric bleeding induced by the luminal administration of supraphysiologic 0.6 N HCl was significantly reduced (50%-70%) if both suckling rats and adults were pretreated per os with raw rat or bovine milk. Pasteurized/homogenized bovine milk also gave protection, although to a lesser extent (30%-50% reduction in bleeding). Treatment of milk with cholestyramine removed 50%-80% of the surface-active phospholipids from milk and also eliminated milk's protective property, an effect that was reversed upon addition of phospholipids to the extracted milk. The antiulcer action of milk in rats could be related to its concentration of dipalmitoyl lecithin. These findings suggest that milk has a potent antiulcer activity that may be attributable to its phospholipid constituents. Published in Gastroenterology (1984)

heat-treating milk intended for calf feeding to eliminate harmful pathogens. Consumers were also advised by the FDA to avoid raw milk, properly handle raw meat Influenza A virus subtype H5N1 (A/H5N1) is a subtype of the influenza A virus that causes the disease avian influenza (often referred to as "bird flu"). It is enzootic (maintained in the population) in many bird populations, and also panzootic (affecting animals of many species over a wide area). A/H5N1 virus can also infect mammals (including humans) that have been exposed to infected birds; in t Birds – Influenza A viruses of various subtypes have a large reservoir in wild waterfowl, which can infect the respiratory and gastrointestinal tract without affecting the health of the host. They can then be carried by the bird over large distances especially during annual migration. Infected birds can shed avian influenza A viruses in their saliva, nasal secretions, and feces; susceptible birds become infected when they have contact with the virus as it is shed by infected birds. The virus can survive for long periods in water and at low temperatures, and can be spread from one farm to another on farm equipment. Domesticated birds (chickens, turkeys, ducks, etc.) may become infected with avian influenza A viruses through direct contact with infected waterfowl or other infected poultry, or through contact with contaminated feces or surfaces. Avian influenza outbreaks in domesticated birds are of concern for several reasons. There is potential for low pathogenic avian influenza viruses (LPAI) to evolve into strains which are high pathogenic to poultry (HPAI), and subsequent potential for significant illness and death among poultry during outbreaks. Because of this, international regulations state that any detection of H5 or H7 subtypes (regardless of their pathogenicity) must be notified to the appropriate authority. It is also possible that avian influenza viruses could be transmitted to humans and other animals which have been exposed to infected birds, causing infection with unpredictable but sometimes fatal consequences. When an HPAI infection is detected in poultry, it is normal to cull infected animals and those nearby in an effort to rapidly contain, control and eradicate the disease. This is done together with movement restrictions, improved hygiene and biosecurity, and enhanced surveillance. Humans – Avian flu viruses, both HPAI and LPAI, can infect humans who are in close, unprotected contact with infected poultry. Incidents of cross-species transmission are rare, with symptoms ranging in severity from no symptoms or mild illness, to severe disease that resulted in death. As of February 2024, there have been very few instances of human-to-human…