Red kidney bean toxins
Red kidney beans form part of the pulses family (which also includes peas and lentils) and are available in both dried and tinned versions. They are often used in recipes such as chilli con carne.
These and other types of beans are considered healthy and nutritious but there is a downside to this. The downside is that they are also capable of causing food poisoning.
Causes of red kidney bean poisoning
The main cause is a toxin called ‘phytohaemagglutinin’ or kidney bean lectin. This is a sugar based protein (glycoprotein) which is found in many types of beans which includes cannellini beans and broad beans.
But some of the highest concentrations of this toxin are found in red kidney beans.
This toxin is killed if red kidney beans are cooked at a high enough temperature and for the right length of time. It is also important that red kidney beans are prepared correctly before use which means soaking them for at least 8 hours before hand.
But if they are cooked for shorter periods of time or at lower temperatures such as those in slow cookers then this will be insufficient to kill this toxin.
Undercooked red kidney beans are more toxic than raw kidney beans.
Symptoms of red kidney bean poisoning
These symptoms appear around 2 to 3 hours after the kidney beans have been eaten. However, it only takes a few beans to cause the following symptoms:
- Abdominal pains
These symptoms appear soon after consumption but, they also disappear quickly as well.
How is this diagnosed?
A diagnosis will be made via a physical examination, these symptoms and the types of foods that have recently been eaten.
Treatment for red kidney bean poisoning
Most cases resolve themselves within a few hours. But there have been cases which have required admittance to hospital. This is usually been due to the quantity of beans consumed and dehydration.
Persistent vomiting or diarrhoea can result in a depletion of fluids, and electrolytes which need to be replaced. This can be done at home via an ‘oral re-hydration’powder which can be purchased at a local pharmacy.
But serious cases of dehydration will require fluid replacement via an intravenous drip.
Preventing red kidney bean poisoning
This type of food poisoning occurs as a result of consuming raw or undercooked kidney beans. So in order to prevent this from happening, take the following precautions:
- Soak the red kidney beans for up to 8 hours. This can be done overnight if you prefer.
- Drain and rinse these beans. Throw this water away
- Put these beans in a pan of cold water and bring to the boil
- Boil them for at least 10 minutes to destroy the toxins
- Simmer them for 45 minutes to an hour
If these beans are still hard in the centre then cook them for longer until they have softened.
Follow any cooking instructions carefully and do not be tempted to shorten the cooking time.
Food Poisoning Guide
- Food Poisoning
- What is food poisoning?
- Food poisoning or gastroenteritis?
- High risk for food poisoning
- Foods which are likely to cause food poisoning
- Types of food poisoning
- Chicken food poisoning
- Beef food poisoning
- Pork food poisoning
- Fish food poisoning
- Ciguatera poisoning
- Scombroid poisoning
- Bacterial food poisoning
- E coli
- Staphylococcus aureus
- Clostridium botulinum
- Campylobacter jejuni
- Vibrio parahaemolyticus
- Vibrio cholerae
- Bacillus cereus
- Clostridium perfringens
- Yersinia Enterocolitica
- Enterobacter sakazakii
- Viral food poisoning
- Entamoeba histolytica
- Mushroom toxins
- Red kidney bean toxins
- Shellfish toxins
- Causes of food poisoning
- Symptoms of food poisoning
- Diagnosing food poisoning
- Treatment for food poisoning
- Home based treatment
- Medical treatment
- Follow up treatment
- Complications of food poisoning
- Lactose intolerance
- Irritable bowel syndrome
- Kidney failure
- Haemolytic uraemic syndrome
- Reactive arthritis
- Guillain-Barre syndrome
- Reporting food poisoning
- Preventing food poisoning
- Cross contamination
- Food irradiation
- Food safety and your family
- Pregnancy and food poisoning
- Babies and food poisoning
- Children and food poisoning
- Teenagers and food poisoning
- Elderly and food poisoning
- Research into food poisoning
- Food Poisoning FAQs