monocytogenes but no significant differences in attachment efficiency were found and for this reason, these results are not given in Table 1. For the frequency effect between the given range for high power ultrasound, it was suggested that the different frequencies of ultrasound treatment had no significant effect on the decontamination efficiency of S. typhimurium (P > 0.05) in the washing of iceberg lettuce,

the average reductions learn more for 25, 32–40, and 62–70 kHz treatments were 1.4, 1.3, and 1.3 log10 CFU/g respectively (not shown in Table 1). The ultrasound application in water significantly reduced the numbers of S. typhimurium (approx. 1.5 log10 CFU/g reduction, 97.9% reduction). These reductions were significantly different (P < 0.05) from the water control in the decontamination of fresh produce. Simple water washings allowed microbial log reductions of 1.43 ± 0.04 CFU/g red bell peppers. Among the technologies applied ozone in aqueous solution, ultrasounds and ultraviolet

C radiation, NVP-BGJ398 datasheet ultrasound was found one of the most effective process. On average, 1.98 ± 0.21 log CFU/g reductions on Listeria innocua occurred when red bell pepper samples had been washed with aqueous ultrasounds ( Alexandre et al., 2013). There are some studies designed to investigate the single and combined effects of ultrasound with some chemicals such as organic acids, acidified sodium chloride, ethanol, chlorine dioxide, and peracetic acid on the microbial inactivation of some fruits and vegetables (Huang et al., 2006, Zhou et al., 2009, Sagong et al., 2011, Rivera et al., 2011 and São José and Vanetti, 2012). Sagong et al. (2011) compared the effectiveness of combining treatments of ultrasound (30 W/L, 40 kHz, 5–10 min) with different organic acid (malic, GBA3 citric and lactic

acids) concentrations (0, 0.3, 0.5, 0.7, 1, and 2), and treatment times (5, 10, 20, 30, and 60 min) with mild agitation at 20 °C against E. coli O157:H7, S. typhimurium, and L. monocytogenes. The maximum reductions of E. coli O157:H7, S. typhimurium and L. monocytogenes were determined as 2.7 (lactic acid), 3.2 (citric acid), and 2.9 (malic acid) log10 CFU/g after a combined treatment with ultrasound and 2% organic acid for 5 min., respectively (P < 0.05). The reduction effect of ultrasound on S. typhimurium, E. coli O157:H7, and L. monocytogenes counts between the 5 and 10 min treatments were not significantly (P > 0.05) different on fresh lettuce in an ultrasound treatment with organic acid applications. The similar data obtained from different studies suggest that the reduction effect of ultrasound occurred primarily during the first 5 min and did not significantly increased even after a 10 min treatment in different samples such as parsley, lettuce, cabbage, carrot, cucumber, strawberry, onion, and pepper (mentioned in Seymour et al., 2002; Sagong et al., 2011). Alegria et al.