FOOD BORNE DISEASES
Food borne diseases and infections are caused by the bacteria present in the food. It is normally possible to identify the bacteria by pathological tests or else it can be identified with their symptoms, duration of illness and incubation period. With regard to their epidemiology, they can be divided into 2 different categories.
1. FOOD BORNE INTOXICATIONS:
Such as Bacillus cereus or Staphylococcus aureus cause toxic food poisoning. The causative micro-organism produces a TOXIN in the food, when they are growing and when a person consumes the food, the toxin is invested and gives rise to the disease. The preformed toxin irritates the lining of stomach, causing vomiting. Some of the toxin pass through the stomach and reach small mates intestine which may result m’ abdominal pain and diarrhea. When the prepared food is heated to a temperature where the bacteria may get destroyed but not the toxins. The incubation period is short from one to Six hours.
2. FOOD BORNE INFECTIONS:
ln this, the causative organisms are ingested; these subsequently grow within‘ the body and cause damage for e.g., infection of salmonella in chicken etc. may cause affection if’ they are consumed. Some of the bacteria are destroyed by the acids present in the stomach but some survive. When they reach to small intestine in neutral condition they start to multiply and irritate the lining causing diarrhea, nausea and abdominal pain. The incubation period is long usually 12 hours or more.
The major food poisoning and infections are being categorized as under:
2. Staphylococcus aureus
4. Clostridium perfringens
5. Bacillus cereus
Salmonella Food Poisoning:
These are small rod shaped bacteria that causes infective food poisoning. They are found in raw meats, eggs, and the presence of the pests is the main source. The animal feed is the basic source of these bacteria. The infected feed is eaten by the animals and become the primary source of infection. These animals carry the infection in their intestine and when they are slaughtered the infectious bacteria spreads on the surface.
Salmonella bacteria are not very resistant to the heat and they get destroyed if heated for one or two minutes in boiling water. Food cooked properly and served immediately will not have these bacteria in it. The problem comes from the raw meat kept with cooked meat and cooked meat is not heated before service. Careless food preparation is the main cause of this food poisoning. If thawing of frozen meat is not done properly the center temperature will not rise adequately and will allow these bacteria to remain in the food and grow. From the hens it is transferred to their eggs and especially the yolk. Even the egg shells do have some infection in them. Eggs should be cooked thoroughly. Cracked eggs should not be used. The incubation period for salmonella is usually 12-24 hours and the main symptoms are diarrhea, abdominal pain, fever, headache and sometimes vomiting. Recovery time is one to seven days. It could be fatal for infants or youngs and elderly persons.
Salmonella organisms have in the past been blamed for many outbreaks in which no definite evidence was available to indicate that they are were the responsible organisms. With our present knowledge regarding food poisoning it appears probable that staphylococci were the etiological agents in many instances.
Different species of Salmonella may be ingested with improperly cooked meats, eggs, and puddings that have been contaminated by rodents or by human carriers. The incubation period is considerably longer than when the preformed staphylococcus toxin is involved since the salmonella organisms require time for multiplication, unless ingested in great numbers.
They are round bacteria that produce a toxin while growing and multiplying on food. It probably accounts for about 90 percent of the outbreaks clue to bacteria. Staphylococcus aureus is commonly found in the nose, mouth, throat in post nasal discharges of those recovering from colds and On the skin, boils and pimples. People who harbor these organisms may contaminate foods ignorantly or carelessly. Cream puffs, chocolate éclairs, cream-filled cakes, chicken gravy, cooked ham, sausage, milk and cheese sometimes caused outbreaks. If these foods are contaminated with staphylococci and then left at warm temperatures for several hours the organisms soon enter the logarithmic growth phase. Multiplication is rapid. Staphylococcus aureus is not very resistant to heat and is destroyed in one or two minutes. However the toxin it produces can withstand boiling for 30minutes. It affects the alimentary tract. Ingestion of food containing this toxin frequently causes a sudden onset of illness, generally within two or three hours.
Typical symptoms include nausea, vomiting, diarrhea, acute prostration and abdominal cramps. Although the patient may be extremely ill, recovery is usually complete within 24 to 48 hours. It is seldom necessary to resort to a stomach pump or to laxatives in order to clear the gastro to resort to stomach pump or to laxatives in order to clear the gastro intestinal tract of the toxin.
The control of staphylococcus food poisoning is an important public health problem. People working in bakeries and kitchens often do not realize that they are adding many staphylococci to foods which serve as ideal media for growth. If the food is not immediately refrigerated, multiplication occurs and toxin may be formed. The incidence of this type of food poisoning could be decreased greatly if sanitary handling and refrigeration of foods is done properly.
It is associated with Food Poisoning Streptococcus jaccalis an enterococcus which produces a green zone surrounding colonies on blood agar plates, has been implicated in a number of food poisoning outbreaks. The greening results from a chemical reaction on the hemoglobin and is referred to as alpha-type haemolysis.
Alpha-type streptococci have been isolated from outbreaks in which those affected had eaten canned Vienna sausages, beef croquettes, coconut- cream pie, and turkey dressing. Symptoms of nausea, vomiting, abdominal pains and diarrhea were experienced 2 to 18 hours after ingestion. In general, symptoms were evident after an incubation period greater than with staphylococcus poisoning, indicating that possibly a growth period was necessary before infection of the intestinal tract occurred. In this event the numbers of organisms ingested would have an important bearing on the onset of symptoms after eating.
They are rod shaped bacteria. They form spores in favorable conditions. Another type of food poisoning is caused by strains of clostridium perfringens. It is present in human and animal intestines and in the soil in the spore form. It therefore comes in the kitchen with raw meat, vegetable or human carrier.
It does not produce toxin while growing but when contaminated food is eaten then it produces toxin in the intestine. The outbreaks are relatively mild and are characterized by colic and diarrhea without vomiting, the majority of cases commencing 10 to 12 hours after ingestion of the contaminated food.
The foods involved are almost always those containing meat and usually have been cooked, allowed to cool slowly, left overnight at room temperature and eat the next day, No toxin seems to be associated with these outbreaks but they appear to be initiated by the ingestion of millions of organisms. Clostridium Perfringens prefer to grow in the absence of oxygen, although it will tolerate a small amount of it.
Outbreak can be prevented by cooking meat shortly before use or by cooling cool meat rapidly and keeping it cold until it is eaten.
Because C. perfringens one of the most widely distributed bacteria it is not possible to prevent food from being contaminated with it; consequently, the only effective methods of prevention are concerned with the inhibition of its growth in articles food.
It’s a rod shaped bacteria that produces a toxin while growing and multiplying o the food. The food poisoning may occur if the contaminated food is eaten. They spores and grow in Favorable conditions.
It is present in the spore form in the rice and other cereals. If rice is cooked an kept at warm temperature for a long time and then eaten without reheating, chances of
Such food poisoning is high. The symptoms are vomiting and diarrhea between one to six hours after eating the food. Incubation period is 8 to 16 hours and recovery occurs within 24 hours.
These are the bacteria associated with the animals. Similar in many ways to Salmonella infection illness is caused by the presence of living bacteria in food when it is eaten. It is not heat resistant so if food is cooked properly and there is no cross contamination with raw food then the chances of food poisoning is negligible.
The animals like dogs, cats, and other pets are the main source and they should not be allowed to come in the food production area or walk on the surfaces to be used for cooking. Wash hands after touching a pet thoroughly.
The incubation period is three to five days and the main symptom is fever followed by severe diarrhea and abdominal pain. Recovery takes from one to ten days.
In any type of food poisoning sufferer should immediately consult the doctor for proper medication and administration.
If metals like arsenic, lead or mercury get accumulated in the body they can be harmful for eg. Lead is a toxic element and contamination of food with lead can cause toxic symptoms. Turmeric is coated by illiterate manufacture in India with lead chromate. Lead brings about pathological changes in the Kidneys, liver and arteries. The common signs of lead poisoning are nausea, abdominal pain, anemia, insomnia, muscular paralysis and brain damage. Fish caught from water contaminated with mercuric salts contain large amounts of mercury. The organic mercury compounds methyl or dimethyl is the most toxic. The toxic effects of methyl mutiny are neurological. When the brain is affected, the subject becomes blind, deaf and paralysis of the various muscles makes him cripple. The other elements which are toxic in mil doses are cadmium, arsenic, antimony and cobalt.