Foreign bodies in food

Not all foreign bodies in food are a health risk. Below are the most common complaints and information on what action you should take.

Insects in tinned foods

Often found in sweetcorn and tomatoes. The grubs are the larvae of a moth, which live inside the kernel/tomato and are impossible to see before processing.

The sterilising and canning process kills them.

No public health risk - contact manufacturer.

Wasps and fruit flies

These are common in tins of fruit. They are naturally associated with ripe fruit and do not carry disease.

No public health risk - contact manufacturer.


Some elements in fish develop into hard crystals during the canning process. You may mistake these crystals for glass fragments, but they are not and are called Struvite. Struvite is not harmful and stomach acids break them down if swallowed. It is especially common in tinned salmon. Struvite crystals dissolve if placed in vinegar and gently heated.

No public health risk.
Contact manufacturer if Struvite.
Contact Environmental Health if glass.


Dented, damaged or incorrectly processed tins may allow mould growth to occur. This could show an error in production or storage.

Possible public health risk – contact Environmental Health.


White fish such as cod or haddock may be infested with a small, round, brownish yellow worm. These are found in the flesh but are killed by cooking and are harmless to humans. The affected parts of the fish are usually cut away, but some may be overlooked.

No public health risk - contact manufacturer.

Glowing Fish (luminous marine bacteria)

Luminous bacteria can sometimes be found on seafood. Items such as crabmeat, cooked shrimp, prawns and simulated seafood products made from surimi are the most common seafoods associated with luminescence or glowing.  When seafood glows it suggests that the food was held for a time at a temperature where bacteria could grow. It does not mean the seafood is unsafe or of low quality. There are no reports of illness from luminous marine bacteria growing on seafood.

No public health risk - return to retailer.

Skin, bone in meat products

Products made from meat and/or poultry may contain small bones, skin or parts of blood vessels.  These are unsightly but rarely a health hazard as they are normal parts of the original animal.

No public health risk - contact manufacturer.

Stones, soil and slugs in fruit or vegetables

Fruit and vegetables commonly have soil, stones or small slugs adhering to them.  This is quite normal as they originate in the soil.

No public health risk - contact manufacturer.


Salad vegetables, especially lettuce, may have greenfly attached. This is becoming increasingly common as the use of pesticides decreases. Greenfly are difficult to wash off but are not harmful - in fact they show that the salad is fresh.

No public health risk - no action required.

Bakery char

Bread and cakes may contain bits of over-cooked dough which has flaked off bakery tins. It is not necessarily an indicator of poor hygiene, although they may be mistaken for rodent droppings. Rodent droppings are black and a regular torpedo shape, while bakery char is greyish and comes in uneven shapes.

No public health risk - contact manufacturer/retailer.

Carbonised grease

The machinery used to produce bread and cakes is lubricated with a non-toxic vegetable oil. Occasionally some may become incorporated into the dough, giving areas of the product a grey/greasy appearance.

No public health risk - contact manufacturer.

Insects in dried foods

Dried products such as flour, sugar and pulses may contain small insects such as psocids (book lice). They do not carry disease but eat through the paper of the packet. They breed very quickly in warm, dark, humid conditions, and spread into uncontaminated food very quickly.

No public health risk - throw out all affected food, clean cupboards with bleach solution and dry thoroughly. Store new dried goods in airtight containers and ensure good ventilation in storage areas.

Bloom on chocolate

Chocolate may develop a light coloured bloom if stored at too high a temperature. It is not mould but is due to fat separation, and it is not harmful.

No public health risk - return to retailer.


Large crystals may form in confectionery and may be mistaken for glass. The crystal will dissolve in warm water.

No public health risk - contact manufacturer.