E. coli is one of the most important pathogenic bacteria, which is a normal inhabitant of large intestine in human and warm-blooded animals [2]. Therefore, E. coli can be transmitted to raw milk and milk products by fecal contamination during milking process along with poor hygienic practices [3,4].
Contaminated foods
Unpasteurized (raw) milk: E. coli on a cow's udder and/or the milking equipment can get into the milk. Drinking contaminated raw milk can lead to an E. coli infection because it hasn't been heated to kill the bacteria.
High prevalence of coliforms and E. coli in raw milk is a cause of concern due to its association with contamination of fecal origin and the consequent risk of enteric pathogenic organisms in food.
A major study reveals for the first time that water troughs on farms are a conduit for the spread of toxic E. coli in cattle, which can then spread the pathogen to people through bacteria in feces.
Out of 380 raw milk samples examined, 129 (33.9%) and 11 (2.9%) were contaminated with E. coli and E. coli O157:H7, respectively.
Does milk have a “built-in” safety mechanism that prevents bacterial contamination? No. Pasteurization is the best way to get rid of harmful germs in milk and the only method regularly used in the United States.
Bacteria present in raw milk are from infected udder tissues (e.g., mastitis causing bacteria), the dairy environment (e.g., soil, water, and cow manure), and milking equipment. High bacteria counts in raw milk only indicate poor animal health and poor farm hygiene.
Some wildlife, livestock, and humans are occasional carriers of pathogenic E. coli and can contaminate meats and food crops. Contamination is typically spread when feces come into contact with food or water.
Healthy colonized cattle and other ruminants are the most significant animal reservoir harboring E. coli O157:H7 (Ferens and Hovde 2011; Munns et al. 2015), and studies have linked ∼75% of the human E. coli O157:H7 outbreaks to food products of bovine origin (Callaway et al.
Once someone has consumed contaminated food or water, this infection can be passed from person to person by hand to mouth contact. E. coli does not survive in the air, on surfaces like tables or counters and is not spread by coughing, kissing or normal, everyday interactions with friends and neighbours.
Keep the milk at the right temperature.
Heat the milk to 63°C (150°F) for at least 30 minutes or 72°C (162°F) for at least 15 seconds.
The notable disease causing bacteria in milk are Salmonella, Brucella, Staphylococcus (S.), Listeria (L.), E. coli and coliforms.
Symptoms include diarrhoea, stomach cramps and occasionally fever. About half of people with the infection will have bloody diarrhoea. People usually notice symptoms 3 to 4 days after they have been infected. But symptoms can start any time between 1 and 14 days afterwards.
Pathogenic bacteria are a serious threat to human health because they can be transmitted through food [2]. Dairy cows are the main source of the E. coli O157:H7 strain that has the potential to contaminate milk and meat through direct contact with cows and the dairy farming environment.
One method for testing for bacteria in milk is to use a culture method, such as the Charm Microbial Peel Plate. This microbial test will detect E. coli and coliforms, aerobic bacteria, and Enterobacteriaceae in milk samples.
There are no antibiotics for most E. coli infections. If you have contracted traveler's diarrhea, your doctor may recommend that you do take anti-diarrhea medications for a short period or bismuth subsalicylate (Pepto-Bismol). In some instances, doctors treat the infection with antibiotics.
Some of the bacteria found in manure, however, is dangerous. Common offenders in cow manure include E. coli, Salmonella, and other pathogens that can make you sick.
Practices to prevent or reduce E. coli O157:H7 contamination of beef carcasses are primarily applied at the processing level, with the most common treatments being hide washes, trimming of contaminated carcass parts, steam vacuuming, hot water and acid washes, and steam treatment (1, 2, 4, 5).
It is transmitted to humans primarily through consumption of contaminated foods, such as raw or undercooked ground meat products, raw milk, and contaminated raw vegetables and sprouts.
E. coli are bacteria found in the intestines of people and animals and in the environment. They can also be found in food and untreated water.
Beyond this stage of milk production, microbial contamination can generally occur from three main sources (Bramley and McKinnon, 1990): from within the udder, from the exterior of the udder, and from the surface of milk handling and storage equipment.
In addition, other pathogens such as salmonella, listeria and the Q fever pathogen can be contained in raw milk. Through sufficient heating of the milk, for example through pasteurisation, ultra heat treatment or boiling, existing pathogens are killed off, however.
Pasteurization involves heating liquids at high temperatures for short amounts of time. Pasteurization kills harmful microbes in milk without affecting the taste or nutritional value (sterilization= all bacteria are destroyed).
The pasteurization time for destroying E. coli and Staphylococcus aureus pathogens is around 30 s, whereas the pasteurization time required for destroying Bacillus cereus is around 90 s. The fate of Listeria monocytogenes can occur during microwave pasteurization of beef frankfurter.