Fresh produce (processed fruit and vegetables) continues to be the main source of foodborne illness outbreaks implicating pathogens such as Escherichia coli O157:H7, Salmonella, Listeria monocytogenes and human parasites (e.g. hepatitis A, Cyclospora). Previously, outbreaks were primarily limited to leafy greens, tomatoes, and cantaloupes, but more recently there has been a trend of more diverse produce types (e.g. cucumbers and papayas) being implicated. Although on-farm good agriculture practices (GAP) contribute to preventing pathogens entering the fresh produce chain, it cannot be relied upon completely due to the open nature of farming. As a consequence, there is an identified need for interventions that can remove field-acquired contamination, especially given fresh produce is eaten raw. In the following review, an overview of foodborne illness outbreaks linked to contaminated fresh produce will be described along with potential sources of contamination. Post-harvest washing that was once considered decontamination is now viewed as a high-risk cross-contamination point. The challenges in monitoring the post-harvest wash process will be discussed along with processing factors that need to be considered. A range of alternative, or supplemental, non-aqueous interventions will be described including irradiation, ultraviolet light, high hydrostatic pressure, gas phase (ozone and chlorine dioxide), and hydroxyl radicals generated through advanced oxidative process or gas plasma. All have been proved to be effective at pathogen control on the laboratory scale and are poised to enter commercial application. The current status of these alternative interventions along with challenges of integrating into commercial practice will be described.

The interaction of a range of Salmonella serovars with pre- and postharvest tomatoes was evaluated. Serovars were selected on the basis of previous association in tomato-linked outbreaks of salmone...

The following reports on the application of a combination of antagonistic bacteria and lytic bacteriophages to control the growth of Salmonella on sprouting mung beans and alfalfa seeds. Antagonistic bacteria were isolated from mung bean sprouts and tomatoes by using the deferred plate assay to assess anti-Salmonella activity. From the isolates screened, an Enterobacter asburiae strain (labeled “JX1”) exhibited stable antagonistic activity against a broad range of Salmonella serovars (Agona, Berta, Enteritidis, Hadar, Heidelberg, Javiana, Montevideo, Muenchen, Newport, Saint Paul, and Typhimurium). Lytic bacteriophages against Salmonella were isolated from pig or cattle manure effluent. A bacteriophage cocktail prepared from six isolates was coinoculated with E. asburiae JX1 along with Salmonella in broth culture. The combination of E. asburiae JX1 and bacteriophage cocktail reduced the levels of Salmonella by 5.7 to 6.4 log CFU/ml. Mung beans inoculated with Salmonella and sprouted over a 4-day period attained levels of 6.72 ± 0.78 log CFU/g. In contrast, levels of Salmonella were reduced to 3.31 ± 2.48 or 1.16 ± 2.14 log CFU/g when the pathogen was coinoculated with bacteriophages or E. asburiae JX1, respectively. However, by using a combination of E. asburiae JX1and bacteriophages, the levels of Salmonella associated with mung bean sprouts were only detected by enrichment. The biocontrol preparation was effective at controlling the growth of Salmonella under a range of sprouting temperatures (20 to 30°C) and was equally effective at suppressing the growth of Salmonella on sprouting alfalfa seeds. The combination of E. asburiae JX1 and bacteriophages represents a promising, chemical-free approach for controlling the growth of Salmonella on sprouting seeds.