If not prepared properly, red kidney beans (and many other members of the lentil family) can cause food poisoning. Or at least might contain some toxins. [via Jack]
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. [emphasis added]
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:
- Nausea
- Vomiting
- Diarrhoea
- Abdominal pains
These symptoms appear soon after consumption but, they also disappear quickly as well.