HOW is my food being fried? That's the question people are being advised to ask by Worcestershire scientists when they buy takeaway food.

This follows an investigation into levels of transunsaturated fatty acids (trans fats) in takeaways.

Worcestershire County Council says it launched the investigation because most consumers are aware saturated fats can have a detrimental effect on the health of their heart, but do not realise that trans fats are just as bad.

Trans fats are found in hydrogenated vegetable oils and have been found to increase the risk of coronary heart disease.

Analysts from the county's scientific services laboratory looked at 22 samples of takeaway food and seven samples of fried snack foods (doughnuts) to compare fat content and also the type of fat contained.

Trans fats were not found in eight of the samples analysed (seven takeaway meals and one doughnut).

In the case of these samples the product was either one that was not fried, or was fried in a pure vegetable oil. The five samples with the highest levels of trans fats were all bought from fish and chip shops. Results taken from Chinese or Cantonese takeaways found no trans fats or only a trace level.

The five samples (all takeaway meals) found to contain more than 5g of trans fats per sample, with one containing 14.1g, were fried in hydrogenated long-life frying oil or hard palm oil.

The public analyst concluded that fish and chip shops using pure vegetable oils or frying in beef fat, would produce a healthier option than using hydrogenated oils.

Hydrogenated oils are often used in takeaways for frying because of the higher temperatures they can reach without burning and the fact they last longer than other products.

Public analyst Carol Stevens said: "Trans fats are difficult to avoid as they're found in processed foods such as biscuits and pastries where hydrogenated fats are often used. But consumers can make a choice when buying their favourite takeaway simply by asking if the frying oil is hydrogenated".

Local businesses are being informed of the results of the project and advised about choosing a healthier alternative frying oil.