Listeria challenge testing


From March 2011 newsletter     
listeria challenge testing

We have recently investigated a novel approach to Listeria challenge testing to see if it would give similar results to the standard more complex methods.

Microbiological challenge tests are essential for assessing the potential for growth of specific foodborne pathogens or spoilage microorganisms in a food product from point of manufacture through to consumption. This involves the inoculation of a product with relevant microorganism(s) and storing under controlled environmental conditions in order to assess the risk of food poisoning or to establish product stability.

Product safety and stability

The use of challenge testing to assess product safety and stability has increased over the past few years, particularly with respect to food pathogens such as Listeria monocytogenes, where evidence is required to demonstrate the potential for growth of this organism throughout life. However, existing recommended procedures are often complex.

New approach

We explored the new approach with a pre-packed sliced ham product. Results showed that a single storage temperature could be used and that a lower temperature could be included in challenge test protocols if this could be maintained throughout part of the manufacture and distribution chain. The need to adapt the cultures by growing under chilled conditions prior to inoculation was also shown to be unncessary.

Contact: Gail Betts
+44(0)1386 842071
g.betts@campden.co.uk