E.COLI:
E.coli is a Gram negative, non-spore forming, facultative anaerobic rods of Family Enterobacteriaeceae. This microbe is mesophillic and grows from 7 - 10 ºC up to 50 ºC (optimum at 37 ºC). With a low minimum water activity for growth at 0.95, pH 4.4 – 8.5. Most E. coli strains are harmless inhabitants of the gut of humans and other warm-blooded animals. Infectious dose of E.coli is 102 CFU/g. In the case of being dried beef of water activity 0.9 and having it to be Barbequed, E.coli is not able to grow or survive at such temperature.
The identified presence of E.coli O157:H7 in related meat outbreaks are, having the cooking heat to be too slow or having short cooking time. When meat is only slightly undercooked this may result in infective dose of the pathogen to be present. E.coli will be present as well when meat is held at room temperature, sometimes even for short periods of time.
Symptoms of E.coli mainly causes diarrhea, abdominal cramps, vomiting and sometimes leading to dehydration.
Beatrice Trum Hunter.2009. Infectious Connections: How Short-term Foodborne Infections Can Lead to Long-term health problems.P55.United States of America: Basic Health Publications
Listeria monocytogenes:
It is a Gram positive, non-spore forming microbe, it is a facultatively anaerobic rod. It is Psychrotrophic and grows at a range of 3 - 4ºC, with an optimum at 30 - 35 ºC, pH 5.0 – 9.0, minimum pH 4.39, aw > 0.92. This microbe is able to grow in the presence of 10% salt content. Growth is enhanced at decreased oxygen levels even when there is presence of carbon dioxide. Listeria monocytogenes is not able to survive heating temperature and time at 60 ºC for 30 minutes. Produces Influenza like symptoms such as fever, headache and occasionally gastrointestinal symptoms. Listeria monocytogenes is mainly found in Water, soil, sewage, decaying vegetables, silage and faeces of numerous wild and domestic animals.
Samonella spp
It is a Gram negative, mesophillic, facultatively anaerobic, motile, non-spore forming rod, grows at 5 - 47 ºC, optimum at 37 ºC, pH > 4.0, minimum pH 4.2, optimum pH at 7.0 and aw >0.95, inhibited by high concentration of carbon dioxide of about 20 – 80% in MAP and salt concentrarion <3% (w/v).
Salmonella spp produces symptoms like Fever, headaches, nausea, vomiting, abdominal pain and diarrhoea . presence of this microbe in domestic animal is highly because of ingestion of the microorganism in food such as milk, meat, poultry and egg derived from infected animals. Food can be contaminated by infected food-handlers, pets and pests, or by cross-contamination as a result of poor hygiene. But with proper pre-requisite and good manufacturing practices in place, the possibility of occurance is very low in terms of contamination of food and water with faeces of infected animal or person. Initial contamination exacerbated by the prolonged storage at temperatures the microorganism is able to grow.
Staphylococcus aureus:
Amount of CFU that can result in health hazards is 105 to 107 cfu/ml with an acceptable number of <100 cfu/g .
S.aureus is a Gram positive, non-motile, non-spore forming, Spherical grape like shape in clusters, facultatively anaerobic coccus, grows at 7 - 48 ºC, optimum at 37 ºC, pH 4.0 – 9.3, optimum pH 7.0 – 7.5, the pH range over which enterotoxin is produced is narrower, with little toxin production below pH 6., 10 - 46 ºC, optimum at 35 - 45 ºC, optimum pH is 6 – 7, while bacterial growth will still occur at aw 0.83, toxin production does not occur below 0.86, this is the most resistant bacteria with regard to reduced water activity. The toxin that causes intoxication is formed in food, is relatively heat stable and can survive boiling for > 1 hour. It is therefore possible for well-cooked food to cause illness without containing viable microorganism.
Infection with this pathogen can cause severe nausea, cramps, vomiting and prostration, sometimes accompanied by diarrhea. If storage conditions are inadequate, the bacteria may multiply to produce toxin. Intoxication is often associated with cooked food via improper handling or contamination. But with proper pre-requisite and good manufacturing practices in place, the possibility of prevalence is very low
Agriculture Research Service, (2010), Pathogen Modeling Program Online, Eastern Regional Research Centre , United States Department of Agriculture, accessed on 30 march 2011 from
N. J. Rowan & J. G. Anderson, (1996), Applied and Environmental Microbiology, Department of Bioscience and Biotechnology, University of Strathclyde, Glasgow, Scotland, accessed 30 march 2011 from
Ibadan Biochemical Communication Group, (1989-2010), Bioline International Official Site (Site up-dated regularly), Environmental Information, CRIA, Brazil, accessed on 30 march 2011 from
Yersinia enterocolitica:
It is a Gram negative, facultatively anaerobic, non-spore forming rod of family Enterobacteriaeceae. Psychrotrophic, grows at 0 - 44 ºC, optimum at 29 ºC, pH 4.6 – 9.0, optimum pH 7 – 8, and in media containing 5% salt, no grow in media containing 7% salt
Causes symptoms like Abdominal pain, diarrhoea, mild fever, sometimes vomiting. It is mainly found in animals.
Clostridium botulinum:
Produces 2 types Exotoxin and enterotoxins . They are mainly found in soil and fecial contamination and passed to animals. Enterotoxins are produced when vegetative cells multiply in intestines
Richard Lawley, Laurie Curtis, Judy Davis , Page 32-35 The food safety hazard guidebooK,By RSC Publishing
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