Chlorine dioxide dose, water quality and temperature affect the oxidative status of聽tomato processing water and its ability to inactivate Salmonella

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• 作者：Gabriela L&oacute ; pez-Velasco^a ; ¹ ; Alejandro Tom&aacute ; s-Callejas^a ; ^b ; ¹ ; Adrian Sbodio^a ; Francisco Art&eacute ; s-Hern&aacute ; ndez^b ; Trevor V. Suslow^a ; ^{tvsuslow@ucdavis.edu}
• 关键词：Tomato postharvest water ; Dump tank ; Chlorine dioxide ; Turbidity ; Salmonella inactivation
• 刊名：Food Control
• 出版年：2012
• 期刊代码：49_09567135
• 类别：abs
• 出版时间：July, 2012
• 卷：26
• 期：1
• 页码：28-35
• 文件大小：409 K

摘要

Water disinfection is a vital control-point to minimize transmission of diverse pathogens from water sources or produce within and among lots at harvest, during initial postharvest handling, and within subsequent postharvest re-packing and processing. The use of ClO₂ as an alternative to NaClO for water disinfection is being adopted by the fresh tomato postharvest handling industry. Lack of data to define performance for this specific water sanitizer under commercial conditions is a barrier to setting meaningful standards and audit criteria for water sanitation and associated food safety goals. The current work aims to establish a correlative capacity of the Oxidation Reduction Potential (ORP) to ClO₂ dose, under different conditions of water turbidity and temperature, and their potential to reflect the efficacy in inactivation of Salmonella enterica in tomato process wash water during primary packing. ORP was monitored at delivered doses of 1, 3 and 5聽mg/L ClO₂, 10, 25 and 40聽掳C water temperature, and varying turbidity (0, 40 and 160 NTU). As main results, inverse correlations between water turbidity, temperature and ORP were observed. An increase in turbidity significantly reduced the final ORP and increased the contact time required for a 5-log inactivation of S. enterica at any assayed temperature. An increase in temperature and ClO₂ concentration reduced the contact time and achieved a 6-log reduction of S.聽enterica within a 2聽min of contact time. Additionally, differences in the required contact time were determined for inactivation of seven different S.聽enterica serovars. ClO₂ was effective in achieving a 6-log reduction, or greater, of S.聽enterica under a range of water quality and temperature. However, water composition strongly affects the dynamic ORP status which can limit total inactivation of S.聽enterica. Data acquired demonstrated the impacts of water quality and temperature to maintain an effective ORP toward inactivation of S.聽enterica. The outcomes of these studies will likely be useful in reassessing the current definition of adequate water quality and safety standards where ClO₂ is used.