Outbreaks of human foodborne illness have previously been reported in Australia and overseas and have been linked to consumption of contaminated fresh horticultural produce. Pathogenic bacteria can survive for extended periods on fresh produce and some products support bacterial growth [1]. As fresh produce is generally not cooked prior to consumption, contaminated produce presents a potential food safety risk to consumers.
In 2005 - 2007, a survey was conducted under the ISFR Coordinated Food Survey Plan to determine the prevalence of microbiological contamination in fresh horticultural produce in Australia. Participating jurisdictions included ACT, NSW, NT, Queensland, SA and Tasmania.
A total of 369 samples were analysed, including lettuce, seed sprouts, strawberries, parsley and basil. The survey collected samples from three points in the horticultural produce supply chain: from the field, at the farm gate and at retail; with the exception of seed sprouts which were collected prior to germination, at the end of the production line and at retail.
Samples were analysed for the presence of Escherichia coli (including verocytotoxin producing E. coli(VTEC) or E. coli O157:H7), Listeria spp. and /or L. monocytogenes, Salmonella spp.
Microbiological status of sampled Australian fresh horticultural produce
| Produce | VTEC | E. coli O157:H7 | Listeria spp. | L. monocytogenes | Salmonella spp. |
| Lettuce | 0 (n=18) | 0 (n=107) | 0 (n=113) | 0 (n=134) | 0 (n=134) |
| Seed sprouts | 1 (n=27) | 0 (n=66) | 2 (n=88) | 0 (n=104) | 0 (n=104) |
| Strawberries | 0 (n=9) | 0 (n=96) | 4 (n=94) | 4 (n=105) | 1 (n=105) |
| Parsley | 1 (n=9) | 0 (n=3) | 0 (n=12) | 0 (n=15) | 0 (n=15) |
| Basil | NT | 0 (n=1) | 0 (n=2) | 0 (n=2) | 0 (n=2) |
NT (not tested)
Results are provided as number of positive samples (n=number of samples tested)
VTEC was detected in one seed sprout sample (broccoli sprouts) collected at the end of production and one sample of parsley collected from the field. Listeria spp. was detected at retail for seed sprouts, while L. monocytogeneswas detected in strawberry samples collected from the farm gate and retail. Salmonella spp. was detected in one strawberry sample collected from the field.
Follow-up action was conducted by the relevant jurisdictions for those samples in which microbiological contamination was detected. The follow-up action included contacting the producer involved (where possible) and reviewing production and handling practices.
While limited by the sample size, this survey provides a snap shot of the microbiological contamination of selected fresh horticultural produce at the time of sampling (2005 - 2007). It confirms that infrequent contamination of fresh produce with potentially harmful bacteria can occur, reiterating the importance for industry and consumers to follow general advice on the safe production, preparation and handling (e.g. washing and refrigeration) of these products.
Since this survey was undertaken, a number of measures have been put in place by the fresh produce industry and jurisdictions to enhance the microbiological safety of these products. More recent surveys of particular sectors of this industry have found even lower levels of microbiological contamination.
See the full report on this survey
[1] NACMCF (1999) Microbiological safety evaluations and recommendations on fresh produce. Food Control 10:117-143.