Inactivation of Escherichia coli and Listeria monocytogenes on iceberg lettuce by dip wash treatments with organic acids

Abstract

Aims: To study and compare the efficacy of organic acids and chlorine dipping in inactivation of Escherichia coli and Listeria monocytogenes on fresh‐cut iceberg lettuce. Methods and Results: Fresh‐cut iceberg lettuce leaves were inoculated with E. coli or L. monocytogenes. After inoculation, samples were stored at 4°C for 24 h and dipped in organic acid or chlorine solutions for 2 and 5 min. E. coli and L. monocytogenes were enumerated on selective media. Treatment of fresh‐cut iceberg lettuce with chlorine solution caused 1·0 and 2·0 log10 CFU g−1 reductions in the number of L. monocytogenes and E. coli, respectively. Maximum reduction for E. coli (about 2·0 log10 CFU g−1) was obtained for samples dipped in lactic or citric acids while maximum reduction for L. monocytogenes (about 1·5 log10 CFU g−1) was attained for samples dipped in lactic acid. Conclusions: Dipping of iceberg lettuce in 0·5% citric acid or 0·5% lactic acid solution for 2 min could be as effective as chlorine for reducing microbial populations on fresh‐cut iceberg lettuce. Significance and Impact of the Study: Dipping in solutions containing organic acids is shown to be effective to reduce E. coli and L. monocytogenes on fresh‐cut iceberg lettuce.

Sanitizing effect of acetic acid (vinegar) on some sliced fruits and vegetables in Kabuga Kano, Nigeria

“…According to Parish et al, (2003), efficacy of treatment depends on Physiology of target microorganism, characteristic of produce surface, exposure time and concentration of sanitizer. The results of this research are in line with the findings of Amoah et al, (2009);Akbas and Olmez (2007) which demonstrated that dipping lettuce in 0.5% lactic and citric acid for 2mins was effective in reducing the microbial population, prior to consumption.…”

Evaluation of Organic Acid-Based Sanitizers for Reduction of <i>Escherichia coli</i> O157:H7 during Flume-Washing of Organic Leafy Greens

“…This indicates that washing for 1 minute would be sufficient to reduce pathogen populations on leafy greens such as baby and mature spinach, and iceberg lettuce. Our results are similar to those obtained by Akbas and Ölmez [26] where no significant differences were observed between treatment times (2 and 5 minutes) to reduce E. coli on iceberg lettuce on day 0. Lin et al [23] also demonstrated that increasing hydrogenperoxide exposure time from 60 seconds to 90 seconds did not significantly affect S. Enteritis, L. monocytogenes and E. coli O157:H7 populations on lettuce leaves on day 0.…”

Microbial Decontamination of Fresh Produce (Strawberry) Using Washing Solutions

“…It was reported that selected house-hold vinegars with concentration of 2.5 and 5% acetic acids were effective in inhibition against L. monocytogenes, E. coli O157:H7, and S. Typhimurium however, only 5% vinegar was effective against S. Typhimurium (Yang, Kendall, Medeiros, & Sofos, 2009). Reduction of L. monocytogenes and pathogens after dipping/spraying or in combination with organic acid solutions has been reported in several studies (Akbas & Olmez, 2007;Nastou et al, 2012). This study investigated the efficacy of dipping/shaking at room temperature with different natural washing solutions containing organic acids in combination with origanum oil and how these solutions reduced micro-organisms in the fresh produce under examination.…”