Real-time PCR methods for the detection of blown pack spoilage causing Clostridium species; C. estertheticum, C. gasigenes and C. ruminantium

Abstract

A set of real-time PCR methods for the detection of C. estertheticum, C. gasigenes and C. ruminantium, the causative agents of blown pack spoilage (BPS) in vacuum packaged beef, was developed. Robust validation of the sensitivity and specificity was carried out in the three matrices (beef meat drip, wet environmental swabs and dry environmental swabs) as encountered in our testing laboratory and against Clostridium strains (n = 76) and non-Clostridium strains (n = 36). It was possible to detect 4–5 spores per ml for C. estertheticum, 2 spores per ml for C. gasigenes and 8 spores per ml for C. ruminantium, without the need for enrichment of the samples. This high sensitivity is particularly important for the beef sector, not just for testing spoiled product but also in the early detection of contaminated beef and in validation of sporicidal cleaning procedures for critical pieces of equipment such as the vacuum packaging machine, which have the potential to contaminate large volumes of product.