Gaseous chlorine dioxide maintained the sensory and nutritional quality of grape tomatoes and reduced populations of Salmonella enterica serovar Typhimurium

Abstract

There have been numerous reports on the effectiveness of gaseous chlorine dioxide (gClO2) in inactivating various human pathogens associated with fresh produce. However, studies dealing with both microbial reduction and impact on quality and nutrients of tomatoes are scarce. In the present study, gaseous chlorine dioxide was evaluated for its effectiveness on populations of Salmonella and native microorganisms on grape tomatoes, and impacts on sensory and nutritional quality. Grape tomatoes, dip inoculated with a cocktail of Salmonella enterica serovar Typhimurium, were treated with three different levels of gClO2 generated by sachets containing sodium chlorite and reducing acids for up to 5 h in 20-L chambers. For the quality study, non-inoculated fruits were treated similarly with the gClO2, and stored for 21 d at 10 °C. Sensory and nutritional quality, and native microflora were measured at 1, 7, 14 and 21 d of storage. Headspace gClO2 concentrations and humidity in the chambers were measured during the treatments. Concentrations of gClO2 in the chamber were relatively stable during the 2.5 and 5 h treatment times. Gaseous ClO2 at 1.9 mg/L for 5 h and 4.3 mg/L for 2.5 and 5 h reduced Salmonella populations from 5.4 log CFU/fruit to a non-detectable level (detection limit 1.70 log CFU/fruit). However, populations of native microflora were not consistently affected by the gClO2 treatments. Furthermore, the treatments did not have any significant effect on appearance, off-odor, firmness, color, or lycopene, and vitamin C contents of grape tomatoes during the 21-d storage. Overall, gClO2 treatments that achieved more than 4 log reductions of Salmonella did not significantly (P > 0.05) affect sensory or nutritional quality of grape tomatoes.