Evaluation of Sanitizing Methods for Reducing Microbial Contamination on Fresh Strawberry, Cherry Tomato, and Red Bayberry.

Wei Wei,Wen Wang,Yuanjing Liu,Yu Zhou,Junfeng Xu,Zhongwen Xie,Haiyan Gao,Xu Wang

doi:10.3389/fmicb.2017.02397

Wei Wei, Wen Wang + Show 6 more

Open Access

https://doi.org/10.3389/fmicb.2017.02397

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Abstract

Strawberries, cherry tomatoes, and red bayberries, which are the most popular types of fresh produce in China, are vulnerable to microbial contamination. In this study, different sanitizing methods [treatment with 2% organic acids, 0.02% sodium hypochlorite (SH), 0.1% sodium chlorite (SC), and 0.1% acidified sodium chlorite (ASC)] were applied to fresh strawberry, cherry tomato, and red bayberry, and their abilities to reduce aerobic bacteria, Escherichia coli O157:H7, mold, yeast, and Salmonella Typhimurium were evaluated. The commercially used SH method reduced the background microbiota on strawberry, cherry tomato, and red bayberry by 0.20–2.07 log cfu/g. The ASC method reduced background microbiota (except for mold) on strawberry and cherry tomato by more than 3.0 log cfu/g. ASC was the only sanitizer that significantly reduced mold on red bayberry, and lactic acid was the only organic acid sanitizer that effectively reduced yeast on red bayberry. The ASC method had the best sterilizing effect on the three fresh fruits and also required the shortest sanitizing time and low chlorite content. The application of ASC method significantly reduced the microbiota on retail grocery samples, and the effect was similar to that achieved by sanitizing methods comparison.

Highlights

In terms of cultivated acreage and production, China is one of the world’s largest producers of strawberry, cherry tomato, and red bayberry
These results indicate that tap water (TW) treatment is not sufficient for sanitizing strawberry, cherry tomato, and red bayberry
The microbial reductions achieved by washing with water were higher for strawberry and cherry tomato than for red bayberry; this may be attributed to the glossy surfaces of strawberries and cherry tomatoes (Velázquez et al, 2009)

Summary

INTRODUCTION

In terms of cultivated acreage and production, China is one of the world’s largest producers of strawberry, cherry tomato, and red bayberry. Because of the low pH values of many fruits, especially red bayberry, the predominant microbiota consists of molds and yeasts (Oms-Oliu et al, 2010) Pathogens such as Salmonella spp. and E. coli often contaminate ground-growing fruits with relatively high pH (e.g., strawberry and cherry tomato) (OmsOliu et al, 2010). The combination of SC and CA produces active ClO2, which is more soluble in water than SH and has an oxidizing capacity two times greater than that of hypochlorite (ClO−); the ASC is more effective at reducing natural microbiota and food-borne pathogens on fresh-cut cilantro and Chinese cabbage (Inatsu et al, 2005; Allende et al, 2009; Prado-Silva et al, 2015). The optimal concentrations and washing times for sanitizing agents (organic acids, SH, SC, and ASC) determined in previous studies were used to sanitize fresh strawberry, cherry tomato, and red bayberry, and the best method for reducing microbial populations

MATERIALS AND METHODS

RESULTS AND DISCUSSION

The Application Results of ASC Sanitizing Method