Effect of post-ripening processing on the histamine and histamine-producing bacteria contents of different cheeses

Histamine is the most active biogenic amine and the one most commonly involved in food-borne intoxications. In this work, the effect of the post-ripening processing (cutting, slicing and grating) of different types of cheese on their histamine and histamine-producing bacteria contents was analysed. The average histamine content detected in Emmental cheeses was 220.8 mg kg(-1); the highest concentrations (up to 734.1 mg kg(-1)) were recorded in grated samples. Significantly more histamine-producing bacteria were detected by real-time quantitative PCR (RT-qPCR) in the post-ripening-processed samples than in entire cheeses in all the cheese types analysed. A good association was obtained between the number of histamine-producing bacteria determined by RT-qPCR and histamine concentrations as determined by HPLC. Results for the analysis of entire Emmental cheeses and their post-ripening processed products suggested that processing had an important influence on the presence of histamine in cheese. (C) 2009 Elsevier Ltd. All rights reserved.