More people than ever before are buying ready to eat food, fast food, and dining out in hotels and restaurants. This change has given people new choices in the food they eat, but it has also created new problems. One of these is the risk of bacterial food poisoning. In the succeeding paragraphs, we shall briefly discuss the causes and sources of food poisoning and measures leading to the access to safe food.
This is the most important element of human life as with little effort and attention we can protect our health, save money on costly treatment and live a longer healthy life.
WHY DOES FOOD POISONING HAPPEN?
Food poisoning bacteria are often present naturally in food, but in numbers so small that the bacteria can multiply frighteningly quickly. In the right conditions, a single bacterium can multiply into more than two million bacteria in just seven hours. So it is very important not to give bacteria the conditions under which they multiply rapidly. The following table will show how quickly bacteria grow:
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Time No. of Bacteria
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12.00 1
12.20 2
12.40 4
03.0 512
05.0 32,768
07.0 2,097,152
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Bacteria grow best when the temperature is between 5c and 60c.This is called the Temperature Danger Zone. We have to make sure that the food is kept in the temperature danger zone for as little time as possible. Bacteria grow and multiply on some types of food more easily than on others. The types of foods which bacteria prefer include: meat, poultry, dairy products, cooked rice and prepared food salads.
These are known as high-risk food. If food is contaminated with food poisoning bacteria and then left in the temperature danger zone, it can cause food poisoning. Bacteria need moisture to grow. If there is no moisture present, the growth of bacteria may slow down or stop. Drying is an effective way to preserve food. Following are the common food poisoning bacteria:
Campylobacter: It is the most common bacteria cause of diarrhea in most of the developing countries including Pakistan. The main sources are raw and undercooked meat and poultry, raw milk and untreated water.
CLOSTRIDIUM BOTULINUM: This organism produces a toxin which causes botulism, a life- threatening illness that can prevent the breathing muscles from moving air in and out of the lungs. The main sources are prepared foods and herbal oils; honey should not be fed to children less than 12 months old.
E.coli: A bacterium that can produce a deadly toxin and causes 73,000 cases of food borne illnesses each year in the United States only. Most of the ailments in our country are directly related to this bacterium. The main sources are meat, and raw milk.
Listeria monocytogenes: Causes listeriosis, a serious disease for pregnant women, new-borns and adults with a weakened immune system; the main sources are soil and water. It has been found in dairy products including soft cheese as well as in raw and undercooked meat, in poultry and seafood.
Norovirus: This virus is the leading cause of diarrhea, food can be contaminated with norovirus if handled by someone who is infected with this virus.
Salmonella: Most common cause of food borne deaths. Responsible for millions of cases of food borne illness a year; the main sources are raw and undercooked eggs, undercooked poultry and meat, dairy products, seafood, fruits and vegetables.
Staphylococcus aureus: This bacterium produces a toxin that causes vomiting shortly after ingesting; the main sources are cooked foods high in protein (eg salads, bakery products and dairy products).
SHIGELLA: Causes an estimated 300,000 cases of diarrhea illnesses. Poor hygiene causes Shigella to be easily passed from person to person. The main sources are salads, milk and dairy products and unclean water.
TOXOPLASMA GONDII: A parasite that causes toxoploasmosis, a very severe disease that can produce central nervous system disorders particularly mental retardation and visual impairment in children. Pregnant women and people with weakened immune systems are at higher risk. The main source is meat.
Vibrio vulnificus: Causes gastroenteritis or a syndrome known as primary septicemia. People with liver diseases are especially at high risk. The main source is undercooked seafood.
For food poisoning to happen there must be a chain of events. There must be bacteria on the food. The bacteria must have the right conditions to grow, that is, warmth (between 5c and 60c), moisture and food. The bacteria must have time to grow and multiply. By preventing each of these we can break the food poisoning chain and prevent food poisoning.
SOME OF THE WAYS TO BREAK THE CHAIN ARE:
-- Make sure hands are clean before handling food;
-- Thoroughly wash and sanitise all equipment used to prepare raw food including benches and chopping boards;
-- Store raw food below cooked food in the refrigerator;
-- Store food correctly, in particular, do not keep food in the temperature danger zone (between 5c-60c);
-- Make sure food is served as soon as possible after preparing;
-- Thoroughly wash fruit and vegetables, including garnishes before using them.
How does food become contaminated: Food may be contaminated because of poor handling and storage or lack of personal hygiene by the people who prepare and serve the food. Food poisoning bacteria are everywhere in the soil, on animals, on people and on the things people touch and use.
It is possible for foods such as meat or vegetables to contain food poisoning bacteria from the start. Even if food is free of bacteria, it can be contaminated by what is called cross contamination. This can happen in two ways (A) During Food Preparation: hands and equipment such as knives and cutting boards can be contaminated with bacteria from raw food. If the same hands or tools are then used to prepare ready to eat or cooked food, without first being properly washed, then this food can become contaminated with bacteria. If this food is not cooked again before being eaten, the bacteria will not be killed and
(B) DURING STORAGE: Bacteria from raw food can contaminate ready to eat or cooked food if they are stored together, so store them separately. If the two types of food are stored in the same refrigerator, the raw food should always be stored lower down than ready to eat or cooked food. This means that the raw food cannot drip onto the cooked food.
There are other ways to spread bacteria. In a food handling or food storage area one should not smoke, chew gum, spit, change a baby's nappy and eat. Hair, jewellery and clothing can also contain and spread bacteria. We should store food in containers that are clean, non-toxic, easy to wash, have tight fitting lids and covered with foil or plastic film.
HOW CAN FOOD POISONING BE PREVENTED: Food poisoning can be prevented by stopping food from being contaminated with bacteria and storing and handling food so that any bacteria cannot grow and multiply. In the right conditions, a single bacterium can multiply into more than two million bacteria in just seven hours. Bacteria are commonly found on the skin and in the nose and mouths of healthy people.
So it is important that everyone maintains high standards of personal hygiene. People with open cuts or wound on their hands and arms must make sure that the injury is completely covered by a waterproof bandage and food handling gloves.
We must wash our hands after going to toilet, handling raw food, blowing our nose, handling garbage, touching our ears, nose, mouth or other parts of the body, smoking, handling animals.
We also need to keep our nails short so they are easy to clean. Nail polish must not be used which can chip into the food. An important way to prevent food contamination is to maintain a high standard of personal hygiene and cleanliness. Even healthy people carry food poisoning bacteria on their bodies.
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