ABSTRACT
The occurrence of Listeria monocytogenes in ready-to-eat (RTE) fish products is well documented and represents an important food safety concern. Contamination of this pathogen in vacuum-packed (VP) smoked fish products at levels greater than the RTE food limit (100 CFU/g) has been traced to factors such as poor sanitary practices, contaminated processing environments, and temperature abuse during prolonged storage in retail outlets. Intervention technologies including physical, biological, and chemical techniques have been studied to control transmission of L. monocytogenes to these products. High-pressure processing, irradiation, and pulsed UV-light treatment have shown promising results. Potential antilisterial effects of some sanitizers and combined chemical preservatives have also been demonstrated. Moreover, the concept of biopreservation, use of bioactive packaging, and a combination of different intervention technologies, as in the hurdle concept, are also under consideration. In this review, the prevalence, routes of contamination, and potential intervention technologies to control transmission of L. monocytogenes in VP smoked fish products are discussed.
ABSTRACT
Sprouts-related outbreaks have risen due to increased raw sprouts consumption. To minimize such cases, chemical sanitations are applied. While chlorine is commonly used, concerns with its effectiveness and health implication have prompted researchers to seek alternatives. Peroxyacetic acid (PAA) has shown efficacy in inactivating foodborne pathogens on fresh vegetables, and hence could be considered as an alternative. Thus, the objective of this study was to compare the efficacy of chlorine and PAA in inactivating Escherichia coli O157:H7, Listeria monocytogenes, Salmonella spp., and natural microflora on mung bean sprouts. Resistance of non- and acid-adapted pathogens to these sanitizer treatments was also evaluated. Un-inoculated and inoculated sprouts were treated with chlorine at 106, 130 and 170 ppm and PAA at 25, 51 and 70 ppm for 90 and 180 s at room temperature. Overall, the greater log reductions were obtained with the increase in the sanitizer concentration. For 180 s, chlorine treatment at 170 ppm reduced 2.0, 1.3, 1.5, 0.9-logs and PAA treatment at 70 ppm resulted in 2.3, 1.8, 2.1, 1.1-log reductions for non-adapted E. coli O157:H7, L. monocytogenes, Salmonella spp., and natural microflora, respectively. These results revealed that the efficacy of PAA was significantly better than or similar to that of chlorine. For acid-adapted cells, these sanitizer treatments were less effective with the ranges of 1.0-1.2-log reductions for chlorine and 1.1-1.6-log reductions for PAA compared to non-adapted cells, indicating that acid-adapted cells were more resistant to the sanitizing treatment. These data suggest that PAA may replace chlorine in the disinfection of mung bean sprouts and that acid-adapted pathogens should be used to design an effective sanitizing strategy.
