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Previous work had shown that the most widely used nitrofuran (furazolidone) was highly unstable in vivo and in vitro. With the impending ban on their use in the EU during the 1990s, some workers began to look for alternative means of detecting their residues. Ultimately, this led to the development of methods to detect the acid-hydrolysable, o nitrobenzaldehyde derivatisable moieties (AOZ, AMOZ, etc) now commonly referred to as the nitrofuran metabolites. A small group of European laboratories continued their work on the detection of these “metabolites” focussing mainly on AOZ, derived from furazolidone. They realised that the current generation of methods were insufficient to enable a proper monitoring of compliance with the incoming ban on the use of the nitrofurans. This group of laboratories eventually formed the core of the FoodBRAND project consortium.

Initially, application of the newly developed FoodBRAND analytical methods uncovered the widespread misuse of nitrofurans in Vietnam (aquaculture) and Thailand (aquaculture and poultry), resulting in the adoption in 2002 of protective measures by the European Commission against both of these countries. Subsequently protective measures were also taken against Brazil, following the reporting of a high prevalence of AMOZ residues in Brazilian poultry exports to the EU (initially approximately 15-20%). The governments and industry in these countries were enabled, through the methods developed by FoodBRAND, to put in place analytical methods that were subsequently deemed by the European Commission to be of sufficient robustness to enable the relaxation and, ultimately, repeal of the these protective measures.

However, it subsequently transpired that the occurrence of nitrofuran residues in food was not restricted to just a handful of countries. The EU’s Rapid Alert System for Food and Feeds has listed the finding of nitrofuran residues in Myanmar, India, Bangladesh, Pakistan, Taiwan, China, Malaysia, Indonesia, United Arab Emirates, Israel, Madagascar, Ecuador, Argentina, Peru, Venezuela, Turkey, Mexico, Bulgaria, Romania and more. In addition, nitrofuran residues were also detected in a number of EU Member States including Portugal, Greece and Italy (by the FoodBRAND retail pork survey) and France, UK and Portugal (by the Rapid Alert system). In 2003, nitrofuran residues accounted for 54% of all Rapid Alerts issued in respect of veterinary drug residues. Most alerts were for AOZ (27%), followed by semicarbazide (SEM) (19%) and AMOZ (8%). By the end of 2004, the situation had improved significantly. The following text is taken from the Annual Report of the Rapid Alert system of the EU:

Nonetheless, nitrofuran residues accounted for 34% of all of the Rapid Alerts issued in respect of veterinary drug residues in 2004 (17% each for AOZ and SEM). Since then, the number of Alerts for nitrofurans has fallen still further. This abuse and misuse of these illegal antibiotics would almost certainly have continued had it not have been for the FoodBRAND project and the products, methods and information that it generated.

The analytical methods developed by FoodBRAND have also highlighted additional problems concerning one of the nitrofuran metabolites namely semicarbazide (SEM). It became apparent that SEM could be detected in a range of materials intended to coat chicken meat during the production of cooked chicken products. Most positive findings were associated with the use of breadcrumbs and other bread products. No obvious nitrofuran-related explanation could be found. However, subsequent investigations revealed that azodicarbonamide, a flour treatment agent that was commonly used in the production of certain breaded chicken products produced in Thailand, was the cause of the problem. The consortium was able to discover that azodicarbonamide breaks down during the bread making process to yield SEM. This emphasized the importance of removing the coatings from chicken (and shrimp) products and of analysing the meat for the presence of bound residues of SEM. The consortium issued advice to this effect in May 2002 and this was subsequently adopted by the EU Community Reference Laboratory in December 2002. The use of azodicarbonamide as a food additive is not permitted in the EU.

In summary, FoodBRAND was funded to improve methods for the detection of a group of antibiotic drugs that had been banned for use in food-producing animals for several years, and for which no satisfactory analytical methods existed. Not only did it succeed in developing (and marketing) these analytical methods, it also enabled the discovery of massive misuse of these compounds throughout the world. Members of the FoodBRAND team assisted governments and industry to establish analytical methods for the nitrofurans and to understand the regulatory issues involved through a series of on-site training events and seminars. Dissemination of the FoodBRAND methods has enabled EU Member States and third countries, alike, to put in place the schemes and policies necessary to eradicate the presence of these residues from the food of the European Consumer. As a consequence, the FoodBRAND team feel that the project was fully vindicated, that it resulted in widespread practical applications and considerable improvements in food safety.

For further information, contact the project co-ordinator, Dr Glenn Kennedy at: info@afbini.gov.uk.