The approach used was as follows:
Data from two FAPAS Rounds (Series 27 - 'Allergens'. Rounds one: wine and two: fish) were critically reviewed to assess the effect of methodological differences on results reported.<p>
Six analytical approaches were selected from the literature. These were identified as the most commonly used procedures and were developed by workers in Netherlands, Spain, France, Germany and the USA. The techniques evaluated included HPLC, fluorometry and ELISA.<p>
The performance of the methods was assessed as applied to five types of food. These were fresh and canned tuna, sardines and mackerel; fresh cheese; and fresh and fermented minced meat and salami. The products were spiked with a low (50mg/kg) level of histamine to represent slightly spoiled samples and at a higher level (200mg/kg) to represent legislative limits. A statistical design was applied to the sample analysis. <p>
A structured objective comparison of methods was produced in terms of recovery, limit of detection, limit of quantification, precision (repeatability) and practicability for application to the food matrices under study. The results were statistically analysed.
Histamine is a biogenic amine. It is produced post mortem in the muscle of Scombroid fish such as tuna and by bacterialogical decarboxylation of the amino acid L-histidine, found in the fish muscle. Fish species that are particularly vulnerable to the development of histamine are those with high levels of free L-histidine in their muscle tissues. Additional histidine may be released during decomposition and spoilage by proteolysis, whereby the protein is degraded and amino acids are liberated. The level of histamine produced in Scombroid or other histidine containing fish by these processes can therefore indicate how much decomposition has occurred.
When present at higher levels, histamine can be a health hazard. It can cause nausea, vomiting, cramps, burning sensation in mouth, itching, uticaria, facial swelling and intense headache. Other biogenic amines such as tyramine, cadaverine and putrescine, often formed in a similar manner in foods, may possibly enhance this toxicity.
Food legislators, consumers and manufacturers have, therefore, a common interest in monitoring levels of histamine in foods. For this reason, the EU has set maximum levels of this substance in bivalve shellfish and fishery products. These limits are taken into UK law through the Food Safety (Fishery Products and Live Shellfish) Hygiene Regulations 1998. The Regulations state that histamine determinations must be carried out in accordance with reliable, scientifically recognised methods, such as high-performance liquid chromatography (HPLC).
The decarboxylation of histidine can also be related to fermentation processes involved in production of foods such as meat and meat products, wines, alcoholic beverages, sauerkraut, yoghurt and cheese. For example, cheese has also been documented as a food borne source of histamine poisoning.
The development of universally accepted or harmonised methods of analysis is essential for the enforcement of food and animal feeding stuffs law under both EU and UK legislation. The variety of existing methods of analysis for histamine may give incomparable results, may not be suitable for all samples types and may not be rugged. Research is needed, to establish the equivalence, accuracy, precision and suitability (including ruggedness) of these methods, and if necessary to refine existing techniques.
<p>Find more about this project and other FSA food safety-related projects at the <a href="http://www.food.gov.uk/science/research/" target="_blank">Food
Standards Agency Research webpage</a>.