A bulletin for the Australian Food Industry May 2000
Contents: Packaged minimally-processed fresh-cut vegetables | Decontamination of fresh fruit and vegetables | Improving the safety of fresh produce | Use of sanitisers at low temperature
Improving the safety of fresh produce
Two brief reviews published subsequent to the WHO document address the same subject in different ways.
In the first of these, (Food Technology 53 (11) 1999 54) John Cherry from the Eastern Regional Research Center, USDA, Wyndmoor, PA, notes that published research on means of eliminating pathogenic microorganisms from fruits and vegetables by washing with antimicrobial agents shows that it is a complex problem. Available processing technologies for washing fruit need to be changed and new washing agents developed to attain efficient removal or inactivation of microorganisms. The author defines the challenge as the attainment of the 100,000-fold kill set by the US Food and Drug Administration (FDA) for selected commodities, e.g. unpasteurised fruit juice.
Cherry covers similar ground to Beuchat, whose published work he draws on, and completes his review on a positive note. He nominates new antimicrobial chemicals, enzymes, and surfactants combined with abrasion and sonication as promising developments.
In the same journal (Food Technology 53 (11) 1999 62) and from the same research institute, authors Thayer and Rajowski discuss developments in the irradiation of fresh fruits and vegetables.
These workers note that while several studies have been published on the irradiation of plants to control plant pathogens, particularly fungi, relatively little effort has been applied to the control of foodborne pathogens on fresh foods. However previous studies on irradiation which did not include its effect on human pathogens have provided data on the radiation doses that these products will tolerate and also on the doses required to inactivate plant pathogens. Present FDA regulations on irradiation do not include the use of irradiation to control foodborne pathogens on fruits and vegetables.
The irradiation of grain, fruits and vegetables is approved by FDA to a maximum dose of 1 kGy for disinfestation.
As remarked upon by other reviewers, Thayer and Rajowski say it is difficult if not impossible to either wash pathogens off produce completely or inactivate them by chemical treatments. Ionizing radiation can penetrate the product to inactivate pathogens that have penetrated the food. They conclude that irradiation is a promising technology that can be used to improve the safety of ready-to-eat fruits and vegetables. Combination of irradiation with other treatments such as chlorination seem especially promising.
How these treatments, even if successful, would affect the marketing and labeling of these products remains to be seen.
Food Science Australia
PO Box 52, North Ryde 1670. Tel +61 2 9490 8397 Fax +61 2 9490 8499
Email enquiries@csiro.au