RESUMEN
The purpose of this study was to evaluate the effectiveness of the combination treatment of lactic acid immersion and saturated or superheated steam (SHS) on inactivation of foodborne pathogens on cantaloupes. Saturated steam (SS) treatments were performed at 100⯰C, while SHS treatments were delivered at either 150 or 200⯰C. Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes-inoculated cantaloupes were exposed to 2% lactic acid or sterile distilled water for 1â¯min followed by a maximum of 20â¯s of SS or SHS. Populations of each of the three pathogens on cantaloupes were reduced to under the detection limit (1.0 log CFU/cm2) after the combination treatment of 2% lactic acid and 200⯰C steam for 20â¯s. To compare the effect of the lactic acid treatment method, we conducted spray application with 2% lactic acid combined with SS or SHS treatment; however, no significant log reduction differences were found between immersion and spraying techniques. After combination treatment of cantaloupes for 20â¯s, color and maximum load values (a characteristic of texture) were not significantly different from those of untreated controls. The results of this study suggest that the combination treatment of lactic acid and SHS can be used as an antimicrobial intervention for cantaloupes without inducing quality deterioration.
Asunto(s)
Bacterias/crecimiento & desarrollo , Cucumis melo/microbiología , Desinfectantes/farmacología , Conservación de Alimentos/métodos , Ácido Láctico/farmacología , Vapor , Bacterias/efectos de los fármacos , Recuento de Colonia Microbiana , Escherichia coli O157/efectos de los fármacos , Escherichia coli O157/crecimiento & desarrollo , Microbiología de Alimentos , Frutas/microbiología , Listeria monocytogenes/efectos de los fármacos , Listeria monocytogenes/crecimiento & desarrollo , Viabilidad Microbiana/efectos de los fármacos , Salmonella typhimurium/efectos de los fármacos , Salmonella typhimurium/crecimiento & desarrollo , Vapor/análisisRESUMEN
The purpose of this study was evaluation of the effectiveness of superheated steam (SHS) on inactivation of foodborne pathogens on cantaloupes and watermelons. Saturated steam (SS) treatment was performed at 100 °C and that of SHS at 150 and 200 °C. Escherichia coli O157:H7, Salmonella Typhimurium and Listeria monocytogenes-inoculated cantaloupes and watermelons were exposed for a maximum of 30 s and 10 s, respectively. Populations of the three pathogens on cantaloupes and watermelons were reduced by more than 5 log after 200 °C steam treatment for 30 s and 10 s, respectively. After SHS treatment of cantaloupes and watermelons for each maximum treatment time, color and maximum load values were not significantly different from those of untreated controls. By using a noncontact 3D surface profiler, we found that surface characteristics, especially surface roughness, is the main reason for differences in microbial inactivation between cantaloupes and watermelons. The results of this study suggest that SHS treatment can be used as an antimicrobial intervention for cantaloupes and watermelons without inducing quality deterioration.