New research funded by the UK's Food Standards Agency could help food manufacturers ensure that the meat-free food eaten by vegetarians and people from certain ethnic groups is not contaminated by meat.
The DNA-based technique called qualitative real-time PCR (QRT-PCR) verified by the research can identify the presence of meat in supposedly vegetarian produce, even at levels as low as 0.05 per cent, although the exact level depends on the actual food.
The analysis of commercial products showed evidence of very occasional low-level contamination consistent with ineffective cleaning procedures by manufacturers. Studies aimed at quantifying the adulteration of vegetarian foods by meat have shown reasonable success if the food analysed does not contain dairy produce.
Food contaminated with animal by-products is unacceptable to vegetarians as well as many ethnic groups. It is also recognised that unacceptable adulterating species varies with ethnic group. To date, no satisfactory methods have been developed to detect the adulteration of vegetable products with products of animal origin.
The new detection method may be used by manufacturers and suppliers to ensure quality control procedures are effective. The method may also be used by the Agency in a future authenticity survey of vegetarian food, although further work is needed if quantification of contaminating species is to be achieved.
A separate study, also funded by the FSA , has developed a screening method that detects meat-derived fats in vegetable fats and oils. The technique works by identifying cholesterol, which is a major component of animal fats but is virtually absent from vegetable fat.
There is an expectation by the public that food labelling is accurate and that techniques are available to confirm the composition of food and food ingredients. Methods to determine whether vegetable fats and oils have been contaminated with animal fats are needed for future surveys. Cholesterol is the major sterol component of animal fats but is virtually absent from vegetable fats and so could be used as a reliable marker for the presence of animal products.
This project examined the cholesterol, phytosterol and sterol degradation product composition of 35 animal fats and 50 vegetable fats. The new method was found to detect 95 per cent of cases where there was a 10 per cent level of animal fat contamination and 90 per cent of cases where there was a 5 per cent level of animal fat contamination.