Foodwise (news articles)
27 August 2015
Standard 1.6.1 – Microbiological Limits in Food was recently amended to include criteria for L. monocytogenes on the basis of whether the food is ready-to-eat (RTE) and can or cannot support growth of L. monocytogenes. The revised Standard was effective from 31 July 2014.
The previous version of Standard 1.6.1 only included a small number of specific foods to which limits for L. monocytogenes applied. This caused inconsistencies in the response to a detection of L. monocytogenes in other foods.
The revised Standard 1.6.1 now specifies:
- For RTE foods whereL. monocytogenes does not grow, a level of up to 100 colony forming units/g (cfu/g) is allowed
- For RTE foods where L. monocytogenes can grow, the limit remains “not detected in 25g”.
The amended Standard recognises that:
- L. monocytogenes is a dangerous microorganism, but more than 100 L. monocytogenes per gram of food are required to cause illness even in the most vulnerable groups.
- Some foods do not allow the growth of L. monocytogenes
- Growth in food is a known cause of foodborne illness
- Appropriate food groups for the organism need to be targeted
- The foods of most concern for L. monocytogenes contamination are those that are RTE (consumed without further processing), undergo slicing or chopping after cooking and are stored at refrigeration temperature for a long period, thereby enabling Listeria opportunity to contaminate and grow to levels of concern.
Businesses preparing food for vulnerable persons may receive certificates of analysis for purchased items with a detection of L. monocytogenes reported. These results could be in the format “<100 cfu/g” or may include a count, up to 99 cfu/g.
The Food Authority recommends that if you have any concern about a product or microbiological test result, you should consult with the manufacturer and/ or vendor to confirm that the pH and/ or water activity of the product do not permit the growth of L. monocytogenes.