Food poisoning is getting sick after ingestion of foods that are contaminated with poisonous substances. These toxins usually come from bacteria, that secrete certain substances that are poisonous to humans and animals. These poisons or toxins remain active, even if the bacteria are dead (for example, by baking or cooking the food).
Food poisoning is caused by eating spoiled or contaminated food. Food can become contaminated at any stage of production, processing or preparation. Food poisoning can be caused by:
- Not cooking food to the proper temperature and/or not using the correct cooking time.
- Not cooling food at the proper temperature.
- Treating food by someone who lacks in adequate personal hygiene when preparing the food, such as washing hands, covering wounds with waterproof patches or wearing disposable gloves.
- Eating food after the expiration date.
- Cross-contamination, where (pathogenic) bacteria of product A end up on product B, by placing the contaminated product to another product, or via hands, kitchen utensils, sink, etc.
The following sources of pollution can be distinguished:
- Bacteria: harmful bacteria are the most common causes of food poisoning. Some of the most common species are the staphylococci, campylobacter, salmonella, listeria and Escherichia coli (abbreviated E. coli and especially the dangerous EHEC-variant).
- Viruses: two common causes of viral food poisoning are the rotavirus and norovirus.
- Parasites: food poisoning caused by parasites is fairly rare in Western countries, but is much more common in third world countries.
- Poisonous substances (toxins): for example by contaminated fish, consumption of poisonous mushrooms, improperly prepared exotic foods or pesticides on fruits and vegetables.
The signs and symptoms are usually diarrhea, poor appetite and nausea. Severe vomiting, abdominal pain, headache, the outbreak of cold sweat and depression may also occur. The symptoms of food poisoning often arise within eight to twenty-four hours after eating spoiled food. Fortunately, the symptoms usually disappear within a relatively short period on their own. The patient may feel weak for some days. Viruses and bacteria can cause infections in the large intestine. These infections often cause bloody diarrhea, nausea and vomiting, abdominal cramps and fever, often accompanied by headache. In some cases, food poisoning can be fatal.
The diagnosis of food poisoning is usually already clear on the basis of the symptoms. In severe cases or when a particular pathogen is suspected, it may be necessary to determine the exact cause. This can be very difficult, but examination of blood, remnants of uneaten food, stool and vomit can help.
In most cases, the symptoms can be combated without consulting a doctor. The most important thing is to ensure that the patient doesn’t dry out and takes time to recover. Avoid dehydration by drinking at least two liters of water per day. In case of loose stools, also drink a large glass of water frequently. In order to prevent dehydration in vulnerable or elderly people, sachets of ORS (Oral Rehydration Salts), dissolved in water, can be used. This product is available at pharmacies.
Antibiotics may be prescribed by the doctor, when examination shows that the food poisoning has a bacterial cause and the symptoms are severe or last longer than three to four days.
The prospects are usually excellent. Most people recover from food poisoning within two days. In case of some (certainly rare) pathogens, or if there are complications in other organs, the prognosis may be less well.
- Cool perishable foods well. Set the refrigerator at 4°C.
- Cool leftovers quickly. Divide them into small portions, which is easier.
- Keep leftovers up to 2 days in the refrigerator.
- Keep things clean and dry.
- Wash hands thoroughly and regularly.
- Wash vegetables and fruits thoroughly under running water and keep the environment clean.
- Separate raw and cooked foods. Don’t use the same cutting board for raw meat and then for cooked food or raw eatable vegetables.
- Heat foods properly. This is especially true for animal products, such as meat, fish and egg. Also heat leftovers thoroughly.
- When buying food, pay attention to freshness, expiration date and preparation and conservation advice.