Food poisoning: Here are the facts

Hardly a day goes by now without a report of children being hospitalised with food poisoning. Some fall ill after eating something they bought from a vendor or spaza shop, while others get sick after eating food prepared for them.

But what is this illness called “food poisoning”? Dr Gerhard Verdoorn, an expert on poisons and operations and stewardship manager at CropLife, says it is important to distinguish between food poisoning and poisoned food.

He said earlier that poisoned food is completely different from food poisoning. Poisoned food is food that became contaminated or was deliberately laced with poison that can cause death. “Food poisoning in common terms is related to food infected by bacteria, which cause severe nausea and vomiting, but seldom leads to death.”

The Consumer Goods and Services Ombudsman (CGSO) says in an advisory note about food poisoning that was compiled in collaboration with Professor Lucia Anelich from Anelich Consulting, that although most people who have food poisoning recover within a day or two and do not need to seek medical help, the condition can become more serious and cause longer-term medical conditions, while some of the most extreme cases may even be fatal.

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What causes food poisoning?

Bacteria and viruses are the more common microorganisms that cause food poisoning and are commonly referred to as pathogens. However, not all foodborne pathogens cause the same symptoms.

The CGSO says some examples of foodborne bacteria and viruses are salmonella, listeria, staphylococcus aureus, certain types of E. coli, shigella, campylobacter, clostridium botulinum, norovirus and Hepatitis A virus.

The most common symptoms of food poisoning are, according to Professor Anelich, vomiting, stomach cramps, diarrhoea, nausea, fever, headache, muscle aches, shivering and tiredness or fatigue. You can have more than one symptom at the same time in some cases.

With norovirus, also known as stomach flu, you can vomit and have diarrhoea at the same time, with some shivering and tiredness.

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Beware: other illnesses could have same symptoms as food poisoning

However, Professor Anelich says it is important to remember that a number of other illnesses have the same symptoms, which makes it difficult to determine if you actually have food poisoning when you show these symptoms.

When people who ate the same food at the same time as you from the same source are showing similar symptoms, it is usually a good indicator of food poisoning.

Some bacteria also target vulnerable sectors of the population, such as young children, people over 65, pregnant women, newborn babies and people with compromised immune systems. People who are living with HIV/AIDS or who are under-nourished, undergoing cancer treatment, had an organ transplant and are on immunosuppressive drugs to avoid the body rejecting the organ, are particularly vulnerable.

E. coli O157:H7 is another serious bacterial disease that causes different symptoms and tends to target young children. It typically causes bloody diarrhoea and causes a significant number of deaths while it can affect the kidneys for life, requiring people to be on dialysis.

It is important to remember that not all food poisoning organisms are found in all foods and different organisms have different “preferences” for foods they can grow on or survive in.

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Cooked foods are generally safer, but not always

The ombudsman says a rule of thumb is that cooked foods are generally safer than uncooked foods, provided these are thoroughly cooked and consumed quite soon after cooking.

It is also very important to keep thoroughly cooked foods refrigerated for a maximum of a few days. Cooked foods can also be potentially dangerous under certain circumstances, such as when food is not prepared under hygienic conditions creating a potential for certain heat-resistant bacterial toxins to be produced in the food.

In this case, cooking may destroy the bacterial cells, but not necessarily the toxins, which may then make you ill. The food could also be contaminated after cooking and if it is not reheated thoroughly before eating it, it can make you sick.

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Certain pathogens that cause food poisoning prefer specific foods

These are examples that illustrate the close association between pathogens and certain foods where foodborne outbreaks have been listed before:

• Listeria in soft cheeses and certain deli meats
• E. coli O157:H7 in undercooked minced meat, such as hamburger patties
• Salmonella in poultry, other meat products and eggs
• Clostridium botulinum causes a severe illness called botulism in traditionally home-prepared salted or fermented foods, such as fish or cured meats and improperly home-canned products.

The ombudsman stresses that most food products in the formal food sector are safe for human consumption. “These foods are produced in plants which undergo regular hygiene and food safety audits to ensure that the food is produced in an environment with good hygiene and good manufacturing practices.”

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How do microbes then get into the food?

According to the ombudsman, several factors determine how foods become contaminated with bacteria, viruses or other microorganisms that can cause foodborne illness, such as:

• Improper hygiene among people handling the food when they do not regularly wash their hands, particularly after being to the toilet and sneezing or coughing into their hands.
• Inadequate cleaning and disinfection of surfaces and the environment. A number of food poisoning incidents occur when cooked food is handled on a surface where raw food is handled and the surface is not cleaned and disinfected first. The raw food’s juices can contain pathogens which can be transferred to the cooked food. This is called cross-contamination and is also applicable to any utensils you use.