A bulletin for the Australian Food Industry February 2002
Contents: Foodborne viral illness in Australia | Foodborne viruses and fresh produce | Prevention of common viral infections | Organic vegetables – microbiology
Organic vegetables – microbiology
Ready-to-eat fruits and vegetables have been associated with microbiological food poisoning incidents in Australia and overseas. This is not in itself surprising but a concern is that with changing production, distribution and marketing procedures, such incidents could become more common and more widespread.
Organic* food is a small but growing part of the food industry in many developed countries including Australia. Manure and other animal and plant wastes are widely used in both organic and conventional agriculture. This gives rise to the possible contamination of produce with microbial pathogens particularly if the manure and other wastes have not been subjected to accepted procedures to minimize risk of pathogen survival (International Food Safety News 8 1999 2).
A recent paper from the UK, where growth in sales of organic fruits and vegetables through major supermarkets has been particularly strong, has produced information which suggests that despite often stated concerns such produce is usually of satisfactory microbiological quality.
In a major study conducted by the Environmental Surveillance Unit of the Public Health Laboratory Service (Letters in Applied Microbiology 33 2001 434), 3200 samples of ready-to- eat vegetables were examined according to a standardized protocol. Samples were collected in England, Wales, Scotland and Northern Ireland. Bacteria tested for were Escherichia coli, Listeria spp. and L. monocytogenes, Salmonella spp, Campylobacter spp. and E. coli O157.
Based on the PHLS microbiological guidelines for some ready-to-eat foods sampled at the point of sale – for E. coli and Listeria this is fewer than 20 colony forming units per gram and the other pathogens must not be detectable in 25 grams – three thousand one hundred and forty-six or 98.5 per cent of the 3200 organic vegetables were satisfactory. A further 39 were acceptable and 15 were of unsatisfactory microbiological quality. Escherichia coli and Listeria spp., not L. monocytogenes, were the microorganisms associated with unsatisfactory results, defined as greater than 100 colony forming units per gram.
No comparable data on the microbiological status of organically grown vegetables in Australia exists in the public domain.
Organic farming in the UK is regulated by EEC Regulation 2092/91 and a program of certification is enforced by local authority Trading Standards Officers and the Register of Organic Food Standards. The EEC Regulation is implemented as the Organic Products Regulation 1992. For a ready-to-eat organic product, the 'processing' must comply with the Regulation as well as the growing system.
In Australia the Australian Quarantine and Inspection Service (AQIS) has developed over many years a National Standard for Organic and Biodynamic Produce. This Standard is mandatory for organic products destined for export. However to gain certification from organizations accredited by AQIS for export purposes, producers for the domestic market have to comply with the same standard. The term 'organic' is not regulated through the Food Standards Code.
Further information on the national standard can be obtained from AQIS: 02 6272 4783. http://www.aqis.gov.au
* Organic food is grown using those principles and techniques that predated the introduction of modern agrochemical and intensive farming techniques (Institute of Food Science and Technology, UK)
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