Food contamination refers to foods that are spoiled or tainted because they either contain microorganisms, such as bacteria or parasites, or toxic substances that make them unfit for consumption. . Most cases of food contamination is from common bacteria such as Staphylococcus or E. coli. Bacteria multiply extremely fast when food is kept at an unsafe temperature.Because the same nutrients in foods are also the same nutrients microbes need for their growth, food spoilage is inevitable. However, most infectious agents do not multiply on foods, but use them as a vector to gain entrance to the human body.
Food contamination can be microbial or environmental, with the former being more common. Environmental contaminants that can enter the food supply chain include pesticides, heavy metals, and other chemical agents. Many opportunities exist for food to become contaminated as it is produced and distributed. To start with, bacteria are present in the animals raised for food. Meat and poultry can become contaminated during slaughter through cross-contamination from intestinal fecal matter. Similarly, fresh fruits and vegetables can be contaminated if they are washed using water contaminated with animal manure or human sewage. During food processing, contamination is also possible from infected food handlers. Lastly, poor hygiene in the home is also a factor.
Food contamination can be divided into three:
1. Food infection : occurs when germs are present in foods and are allowed to multiply until there is enough of them to cause sickness.
2. Food intoxication: occurs when microorganisms that are present in food produce a toxin and it is the toxin the causes the illness rather than the actual microorganisms.
3. Chemical contamination: caused by contamination of food by chemicals such as pesticides (used in insect and rodent control), certain cleaning compounds, and sometimes by use of improper containers (pots) for cooking or storing food.
Food poisson can affect one person or a group of people who all ate the same contaminated food. It more commonly occurs after eating at picnics, school cafeterias, large social functions, or restaurants.
The germs may get into the food you eat in different ways:
• Meat or poultry can come into contact with the normal bacteria from the intestines of an animal that is being processed.
• Water that is used during growing or shipping can contain manure or human waste
• Food handling or preparation in grocery stores, restaurants, or homes
Food contamination often occurs from eating or drinking:
• Any food prepared by someone who does not use proper hand washing techniques
• Any food prepared using cooking utensils, cutting boards, and other tools that are not fully cleaned
• Dairy products or food containing mayonnaise (such as coleslaw or potato salad) that have sat out of the refrigerator too long
• Frozen or refrigerated foods that are not stored at the proper temperature or are not reheated properly
• Raw fish or oysters
• Raw fruits or vegetables that have not been washed well
• Undercooked meats or eggs
• Water from a well or stream, or city or town water that has not been treated
Germs that cause disease are also spread by:
• poor personal hygiene habits of food employees
• people who may seem well but who carry bacteria that can make other people sick
• improperly cleaned and sanitized eating and cooking utensils and equipment
• contamination of food, utensils, and equipment from flies, roaches, and other insects and pests
• use of foods from unapproved sources
Food poisoning can be caused by any of the following bacteria :
• Botulism (Clostridium botulinum)
• Fish poisoning
• Many different viruses
• Staphylococcus aureus
Pregnant and breastfeeding women have to be especially careful to avoid food poisoning.
Infants and elderly people are at the greatest risk for food poisoning. You are also at higher risk if:
• You have a serious medical condition, such as kidney disease or diabetes
• You have a weakened immune system
• You travel to areas where there is more exposure to organisms that cause food poisoning
The symptoms from the most common types of food poisoning generally start within 2 - 6 hours of eating the food. That time may be longer (even a number of days) or shorter, depending on the cause of the food poisoning.
• Weakness (may be serious and lead to respiratory arrest, as in the case of botulism)
Exams and Tests
A health care provider can examine for signs of food poisoning, such as tenderness in the abdomen and dehydration. Tests to find the cause may be done on :
• Leftover food
Even if you have food poisoning, however, these tests may not be able to prove it.
In rare but possibly serious cases, a health care provider may do one or more of the following procedures:
• A thin, tube-like tool placed in the anus to look for the source of bleeding or infection (sigmoidoscopy)
• A test to measure electric impulses in the muscles (electromyography) to check for botulism
• A test of fluid from the spine (lumbar puncture) if you have signs of a nervous system disorder
One will usually recover from the most common types of food poisoning within a couple of days. The goal is to avoid dehydration.
• Don't eat solid foods until the diarrhea has passed, and avoid dairy products, which can worsen diarrhea (due to a temporary state of lactose intolerance).
• Drink any fluid (except milk or caffeinated beverages) to replace fluids lost by diarrhea and vomiting.
• Give children an electrolyte solution sold in drugstores.
Dehydration is the most common complication. This can occur from any of the causes of food poisoning.
Less common but much more serious complications include:
• Arthritis (Yersinia and Salmonella)
• Bleeding disorders (E. coli and others)
• Death (from mushrooms, certain fish poisonings, or botulism)
• Kidney problems (Shigella, E. coli)
• Nervous system disorders (Botulism, Campylobacter)
• Pericarditis (Salmonella)
• Respiratory distress, including the need for support on a breathing machine (botulism)
Preventing food contamination
To prevent food poisoning, take the following steps when preparing food:
• Carefully wash hands often, and always before cooking or cleaning. Always wash them again after touching raw meat.
• Clean dishes and utensils that have had any contact with raw meat, poultry, fish, or eggs.
• Use a thermometer when cooking. Cook beef to at least 160°F, poultry to at least 180°F, and fish to at least 140°F.
• DO NOT place cooked meat or fish back onto the same plate or container that held the raw meat, unless the container has been completely washed.
• Promptly refrigerate any food you will not be eating. Keep the refrigerator set to around 40°F and your freezer at or below 0°F. DO NOT eat meat, poultry, or fish that has been refrigerated uncooked for longer than 1 to 2 days.
• Cook frozen foods for the full time recommended on the package.
• DO NOT use outdated foods, packaged food with a broken seal, or cans that are bulging or have a dent.
• DO NOT use foods that have an unusual odor or a spoiled taste.
• DO NOT drink water from streams or wells that are not treated. Only drink water that has been treated or chlorinated.
Much care should be done when handling, eating and giving out food. In normal cases the food may seem so appetizing but not knowing that it contains a lot of microorganisms which leads to food contamination. There are a lot of precautionary measurements stated above should be taken note of.
1. Department of Health and Human ServicesNational Institutes of Health, Food contamination, 2010, [Online] available at
2. Diet Health, Food contamination, 2010, [Online] available at
3. Food contamination, 2010, [Online] available at
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