Purpose: The objective of this study was to investigate the efficacy of a citric acid based organic sanitizer (organic ChicowashTM) against Salmonella enterica serovar Newport and background microflora on celery and leeks.
Methods: Three different concentrations (1:10, 1:20 and 1:40) of Chicowash solutions were used. De-ionized water and 200 ppm chlorine were used as controls. For background microflora testing, 10 g fresh cut celery or leeks were weighed for each sample. For Salmonella testing, produce samples were washed, dip inoculated in 107 CFU/ml Salmonella Newport culture and allowed to dry for 30 min to facilitate bacterial attachment. Samples were immersed in the sanitizer solutions for 2 min. Samples were taken for enumeration of survivors after storage at 4°C for 0, 1, 3 and 6 days.
Results: At day 6, Chicowash reduced Salmonella and background microflora population by 0.7-1.5 and 1.2-2.6 logs CFU/g, respectively. All three concentrations showed 0.3-1.0 log additional reduction in Salmonella population on celery and leeks than 200 ppm chlorine. At day 1, Chicowash showed 0.8-1.3 logs reduction in Salmonella population. At day 3, the reductions in Salmonella population were 1.3-1.6 and 0.7-1.6 logs on celery and leeks, respectively. At day 0, after Chicowash 1:10 treatments, the background flora population on leeks were 1.8 logs lower than that of 200 ppm chlorine treated samples. At day 6, background microflora population on celery and leeks samples were 1-1.7 and 1.5-2.2 logs less, respectively, than that on chlorine treated samples. The antimicrobial activity of Chicowash was concentration and storage time dependent.
Significance: The results could provide the fresh-cut produce industry with additional options to select organic sanitizers for post-harvest treatments.