Aug 12 2006
Some recent media reports about the potential hazards of contamination of foodstuffs by latex proteins in food contact materials, eg packaging, are highly misleading and likely to cause alarm amongst the general population.
As often happens when science is reported in the popular press, quite complex concepts, research techniques, results, discussion and conclusions are encapsulated in a few brief sound bites to attract the reader.
In this instance, a detailed scientific paper, which was published on 7 August 2006 by the Society of Chemical Industry (SCI) in the online edition of Journal of the Science of Food and Agriculture, has been summarised in the SCI’s magazine Chemistry and Industry and in a related press release. The resulting media reports have highlighted some aspects of the work but ignored other important points.
The work, carried out by Leatherhead Food International on behalf of the Food Standards Agency (FSA), is pioneering research. As noted in the Chemistry & Industry article, “This is the first attempt to comprehensively quantify the latex allergens in food and food packaging.” No attempt has previously been made to investigate the levels of latex proteins (or more correctly, latex allergens) which could potentially be extracted from food contact materials, nor has there been any work which studied the potential for such allergenic proteins to be transferred to the foodstuff. The methods used for testing levels of latex proteins in products (typically latex gloves) are not suitable or sensitive enough for this purpose. The researchers therefore had to devise their own new methods and test them out. This is all that this piece of research has achieved. It has demonstrated that, using the method devised, it can be shown that four particular latex proteins, known to cause allergic reactions, can be extracted from certain food contact materials (but not all four proteins can be easily extracted using this same method) and that there may - and the researchers are careful in their wording - be a possibility of the latex proteins transferring to some foodstuffs. In some cases, there is no absolute certainty that the protein found is actually from latex - for instance, it could be from certain fruits which are known to contain similar proteins. The researchers are also careful to point this out.
Reports have suggested that one third of the products tested contained identifiable latex proteins. It is true that seven out of 21 food contact items were seen to contain one or more of the protein allergens at a level above a certain arbitrary figure (over 10 ng/ml), but the products were deliberately chosen in such a way that it was very likely that latex was one of the materials used in the product. It has also been quoted that the level of proteins in one chocolate biscuit was 20 times that known to be capable of causing a reaction. This is true according to the figures tabulated, but this statement should be treated with caution. There is only one single reference (cited by the Leatherhead researchers) which provides the figure of 1 ng/ml which is reported as the level at which an allergic reaction can take place “in sensitive individuals”. The word “sensitised” would normally be the one used to describe people who have been tested and found to be most likely to experience allergic reactions to a certain substance. It should be noted that this figure of 1 ng/ml is based on the result of one previously sensitised individual reacting to a particular protein allergen (Hev b7) which was not, in fact, one of the four proteins tested by Leatherhead.
The methods used in this study have not yet proved to be reliable. This study will be the basis for a new research project which Leatherhead has already embarked on. Scientists who are familiar with the methods used in testing for latex proteins in a variety of products provided comments during the report drafting period. They expressed concern that the units used by Leatherhead for making the comparisons between the protein levels in the products and in the foodstuffs were likely to be confusing.
The new project, started by the FSA to improve on the test methods developed, is described on its website and is also being conducted by Leatherhead Food International. The new work aims to develop reliable, validated test methods for the extraction of all the latex allergens present in food contact materials, in particular cold seal adhesives and bakery release films. A second laboratory will apply the method to industrial samples, and it will also be tested on foods collected from food manufacturers. Only when these results have been published will it be possible to tell whether a reliable test method might have been established. Until that point, the FSA is right to be cautious in its statement reported by the BBC, “The FSA advises consumers not to change what they eat or how they prepare it, as it is not clear that there actually is transfer of allergens from latex to food outside the laboratory.”
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