The Food Safety Authority of Ireland reports this survey investigated the microbiological safety of ready-to-eat, pre-cut and pre-packaged fresh herbs and salad leaves available at retail sale in Ireland.
Over 1,000 samples were tested for the presence of Salmonella and enumerated for Listeria monocytogenes. Salmonella was detected in only 0.1% (1/1,005) of samples; this was a bag of rocket leaves grown in Italy from which S. Napoli was isolated. L. monocytogenes was below the limit of enumeration (<10 cfu/g) for 99.8% (998/1,000) of samples and at 10 cfu/g for the remaining two samples, all well below the maximum legal limit of 100 cfu/g.
Some samples were tested for the presence of verotoxigenic E. coli (VTEC). In total, 0/247 samples tested using the CEN/ISO TS 13136 method (which targets the major VTEC virulence genes stx and eae) were positive. In addition, 0/397 samples tested specifically for E. coli O26 were positive and although 1/403 samples tested specifically for the presence of E. coli O157 was positive, the isolate did not contain the genes required to produce verotoxin and therefore, was not of clinical significance.
This survey was carried out from June to October, the months when Irish produce was most likely on sale. Irish origin produce made up 62% of the samples tested in this survey, none of which were unsatisfactory.
Producers labelled fresh herbs and salad leaves with a wide range of storage instructions, particularly in relation to the temperature for chilled storage. Maximum storage temperatures as low as 3oC were recommended by some producers; however, the national recommended temperature for chilled storage is 0-5 oC. Food business operators that package ready-to-eat, pre-cut, fresh herbs and salad leaves should also be aware that the temperature in domestic fridges is generally higher than at retail and wholesale level.
In total, 87% of samples were stored or displayed in refrigerated conditions at the time the sample was collected.
The air temperature of the refrigeration unit for the majority (77%) of these samples was ≤5 oC. However, the air temperature of the refrigeration unit for 23% of chilled samples was >5oC. Indeed, an air temperature of 7.1oC was measured for the refrigeration unit in which the Salmonella-positive bag of rocket leaves was stored. This temperature could allow Salmonella numbers on the already contaminated product to increase if the shelf-life is sufficiently long. Food business operators should ensure that refrigeration units do not exceed the maximum chilled temperature of 5oC.
The bag of rocket in which Salmonella was detected was labelled as already washed. Washing (with or without the presence of sanitisers) cannot eliminate pathogens on fresh produce. Therefore, producers must take all reasonable measures to control potential points of contamination in the field, during harvesting, processing and distribution; for example using guides to good practice such as the Food Safety Authority of Ireland (FSAI) Code of
Practice for Food Safety in the Fresh Produce Supply Chain (FSAI, 2001a). In addition, food business operators should ensure that their traceability records for the fresh herbs and salad leaves are robust, as this will facilitate rapid control measures to be implemented should a pathogen be detected in a batch of fresh herbs or salad leaves or if they are implicated in an outbreak of illness. The FSAI has produced Guidance Note No.10 on
Product Recall and Traceability (FSAI, 2013).
Survey of the microbiological safety of ready-to-eat, pre-cut and pre-packaged fresh herbs and salad leaves from retail establishments in Ireland (13NS7)
Food Safety Authority of Ireland, May 2015