New Method to Detect C. Botulinum Spores

NORWICH, United KingdomResearchers at the Institute of Food Research and the Nestlé Research Centre have developed a new method for detecting non-proteolytic Clostridium botulinum spores.

The majority of cases of foodborne botulism are caused by two bacterianon-proteolytic C. botulinum and proteolytic C. botulinum. Non-proteolytic C. botulinum is able to grow and produce toxin at 3°C; proteolytic C. botulinum will not grow at temperatures less than 12°C. This ability to grow at form toxin at refrigeration temperatures makes non-proteolytic C. botulinum a major hazard in minimally heated refrigerated foods, such as refrigerated convenience meals.

The new method is designed to provide the data the food industry needs for quantitative microbial risk analysis and the implementation of food safety objectives. It allows the total risk from spores of non-proteolytic C. botulinum in the final meal to be calculated. Modeling the risk of this total spore count rising above safe levels and the frequency that this event occurs will allow the management and control of the process more accountably.

The production incorporates practices and risk assessments based on the latest scientific information, such as spore heat resistance, growth properties of non-proteolytic C. botulinum, and the incidence of these spores in food. The new method of detecting non-proteolytic C. botulinum is providing high quality information on the incidence of spores in food. An important feature of the new method is that it is specific, and enumerates only non-proteolytic C. botulinum spores. Previous techniques were not optimized to distinguish between non-proteolytic C. botulinum and proteolytic C. botulinum. The new method is very sensitive with a low detection limit that has been achieved by the use of a selective enrichment and large test samples, and importantly this has been confirmed using carefully structured control samples.