Inter-laboratory validation of a method for detecting previously frozen poultrymeat by determination of HADH activity

Poultry is a perishable product which requires careful control of temperature during production and retail processes. The EU poultry marketing legislation requires that poultry be marketed either as fresh poultry or as frozen (or quick-frozen) poultry. It is not permitted to market poultry which has been frozen and thawed as fresh poultry. A robust analytical method that is capable of distinguishing between fresh and previously frozen poultry is therefore required. A method to detect whether poultry and other meats had been previously frozen was developed in earlier work and was validated by collaborative study in the UK in 1997. The method relied on measuring the hydroxyacyl-CoA-dehydrogenase (HADH) activity of intracellular juice obtained from the test samples. The ratio of the HADH activity of sub-samples tested before and after laboratory freezing is compared to a reference cut-off limit to determine whether the sample has previously been frozen.