How much water is in your food?

When you shell out for succulent scallops and large prawns - at £1.10 each and £31 a kilo respectively - you could be paying for added water - up to 50 per cent according to a Food Standards Agency report published last week.

Food labelling law states that products containing more than five per cent added water must declare it, but because of a loophole some foods don't have to. Seafood sold loose at fish counters, or hams with added soya or starch, do not have to state their percentage of added water. And water added to rehydrate a dried ingredient - such as powdered egg - also doesn't need to be labelled. Similarly, frozen prawns don't have to spell out their water content.

Surprisingly, there are virtually no restrictions on the maximum amount of water a food can contain. All foods naturally have a high percentage of water, but it can also be added to cheap foods to increase their weight so they can be sold for more profit.

"Consumers are being duped by manufacturers who are adding water to bulk up the size and weight of produce, and what's worse, it isn't possible to work out from the label how much water has been added,î says Ian Tokelove of the Food Commission.

Fresh scallops

Added water: Up to 54 per cent. A Food Standards Agency survey found that nearly half of all scallops tested had 10 per cent added water - some contained 54 per cent. Water is used in the preparation of shellfish, so it's impossible to avoid, but more than 10 per cent is not acceptable according to good manufacturing practice.

Frozen scampi and prawns

Added water: Up to 44 per cent. The FSA found that 86 per cent of samples of ice-glazed, peeled scampi exceeded 15 per cent, the maximum limit for water that is needed to keep them in good condition. Frozen prawns are
labelled with their weight excluding glaze, which should give you a much better idea of how much ice you're paying for. But the net weight can still include water that was absorbed into the prawns before they were frozen.

Supermarket poultry

Added water: Up to 37 per cent. The EC limit for added water in a frozen, whole chicken is seven per cent, but nearly a third of samples contained more than that in an FSA survey. Chicken breast and thigh portions contained water levels from two to 37 per cent, with frozen portions being the worst offenders. In more than 10 per cent of the breast-and-thigh samples, the added water was not listed anywhere on the packaging.

Restaurant chicken

Added water: Up to 40 per cent. Some restaurants were found to be serving meat that contained only 54 per cent actual chicken, according to an FSA survey last year. Catering packs of chicken can be injected with water, salts, flavourings and hydrolysed protein, which retains moisture.

Bacon

Added water: Up to 25 per cent. Most bacon contains added water, which is introduced during the curing process when the meat is injected with, or immersed in, brine. Currently, uncooked bacon only has to be labelled when its water content exceeds 10 per cent. So bacon said to contain "not more than 15 per cent added waterî can legally contain up to 25 per cent.

Ham

Added water: Up to 30 per cent. By law, all added water should be listed on cooked ham unless other ingredients - such as gelatine, soya, starch and milk protein - have also been added. But even when added water is given on the label, the figure can be misleading as the amount is defined as the water content over and above what is in the meat when raw. As meat loses water when it's cooked - usually at least 10 per cent - manufacturers can add this amount without having to declare it.