The use of an automated system for mutagenicity testing to assess the inner quality of heat-treated orange juices

The Cobas Bact automated microbiological growth analyser was used to explore the feasibility for automation of a Salmonella mutagenicity assay for heat load measurement of orange juice. The results indicated that endogenous growth factors, e.g. histidine present in whole orange juices and cytotoxic effects of the heated juices disturb the turbidometric assay system. Good results were obtained with gel filtration and HPLC fractions of the juice. It is concluded that for the screening of fractions, with a view to collecting material for the chemical identification of mutagenic Maillard intermediary products, the automated system may be helpful.