Nut hazards

Avoid eating almonds which have not fully matured as they can contain compounds which produce hydrogen cyanide, a poisonous gas which has a distinctive aroma of bitter almonds. The shells of immature nuts may be slightly softer and are sometimes tinged with green, rather than the normal light brown.

Nuts should be stored in cool, dry conditions because they are prone to contamination with moulds. Some of these produce poisonous substances called mycotoxins, so never eat nuts with any trace of mould on the shell or kernel. In tropical countries, mouldy nuts may contain more dangerous mycotoxins - called aflatoxins - which cause liver cancer. These were identified in England in the 1960s when there was a large outbreak of liver disease in turkeys which had been fed on peanut meal. Peanuts are particularly prone to this form of contamination and, even though those imported into Britain are routinely checked for these moulds, it is safest to eat only peanuts that are sold in packets. Children should never be allowed to eat peanuts sold for use as birdfood.

Choking is one of the greatest hazards posed by nuts: for this reason, children under the age of four, who may not chew their food properly, should never be given nuts unless they have been finely ground.

Allergy alert

Nuts, especially peanuts, are one of the most common food allergens. In exceptional instances nut allergies can be fatal. Fortunately, such serious allergies are extremely rare, but people who are allergic to peanuts have to avoid all foods that contain even the tiniest traces of peanuts or peanut oil. Unfortunately, peanut allergy is normally a life-long condition.