Ready-to-eat vegetables: Current problems and potential solutions to reduce microbial risk in the production chain

Castro-Ibáñez, Irene; Gil, María I.; Allende, Ana

doi:10.1016/j.lwt.2016.11.073

Cited by 114 publications

(84 citation statements)

References 70 publications

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“…After processing, produce should be stored and transported in temperatures that prevent microbial growth, and special attention should be given to the quality of water used to refrigerate the foodstuffs, be it for preparing ice, or to use in different cooling approaches, such as hydrocooling (Castro‐Ibáñez et al., ). The hygiene and microbial safety of cooling rooms in processing plants is also of utmost importance.…”

Section: Resultsmentioning

confidence: 99%

“…The efficiency of antimicrobial treatments used can also be affected by the presence of high organic matter content in washing water, resulting from the accumulation of soil, debris, and cut‐produce tissue fluids from RTE crops (Allende, Selma, Lopez‐Galvez, Villaescusa, & Gil, ; Luo, ). The maintenance of cold storage conditions throughout processing, shipping, storing, and retail of fresh produce is of crucial importance, as low temperatures will hinder the proliferation of bacterial pathogens during these steps (Castro‐Ibáñez, Gil, & Allende, ). Failing to maintain these conditions during storage and/or transportation of these commodities will favor proliferation of bacteria if they are already present on produce (Zeng et al., ).…”

Section: Introductionmentioning

confidence: 99%

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Microbial Contamination of Fresh Produce: What, Where, and How?

Machado-Moreira

Richards

Brennan

et al. 2019

Comp Rev Food Sci Food Safe

174

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Promotion of healthier lifestyles has led to an increase in consumption of fresh produce. Such foodstuffs may expose consumers to increased risk of foodborne disease, as often they are not subjected to processing steps to ensure effective removal or inactivation of pathogenic microorganisms before consumption. Consequently, reports of ready‐to‐eat fruit and vegetable related disease outbreak occurrences have increased substantially in recent years, and information regarding these events is often not readily available. Identifying the nature and source of microbial contamination of these foodstuffs is critical for developing appropriate mitigation measures to be implemented by food producers. This review aimed to identify the foodstuffs most susceptible to microbial contamination and the microorganisms responsible for disease outbreaks from information available in peer‐reviewed scientific publications. A total of 571 outbreaks were identified from 1980 to 2016, accounting for 72,855 infections and 173 deaths. Contaminated leafy green vegetables were responsible for 51.7% of reported outbreaks. Contaminated soft fruits caused 27.8% of infections. Pathogenic strains of Escherichia coli and Salmonella, norovirus, and hepatitis A accounted for the majority of cases. Large outbreaks resulted in particular biases such as the observation that contaminated sprouted plants caused 31.8% of deaths. Where known, contamination mainly occurred via contaminated seeds, water, and contaminated food handlers. There is a critical need for standardized datasets regarding all aspects of disease outbreaks, including how foodstuffs are contaminated with pathogenic microorganisms. Providing food business operators with this knowledge will allow them to implement better strategies to improve safety and quality of fresh produce.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microbial Contamination of Fresh Produce: What, Where, and How?

Machado-Moreira

Richards

Brennan

et al. 2019

Comp Rev Food Sci Food Safe

174

View full text Add to dashboard Cite

show abstract

“…Surrogate infectivity versus molecular reductions. Viruses are a known public health concern associated with the consumption of leafy green vegetables (5,(37)(38)(39)(40), and a number of studies have been performed investigating the reduction of viruses on leafy greens during postharvest processing (11,(41)(42)(43)(44)(45). Baert and colleagues have also shown that viruses can persist in leafy green wash water for long periods of time when left untreated after they observed no meaningful reduction of MNV in industrial spinach wash water for up 6 days (43) and in shredded lettuce wash water for up to 40 h (42).…”

Section: Discussionmentioning

confidence: 99%

Inactivation of Human Norovirus Genogroups I and II and Surrogates by Free Chlorine in Postharvest Leafy Green Wash Water

Dunkin

Weng

Jacangelo

et al. 2017

Appl Environ Microbiol

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Human noroviruses (hNoVs) are a known public health concern associated with the consumption of leafy green vegetables. While a number of studies have investigated pathogen reduction on the surfaces of leafy greens during the postharvest washing process, there remains a paucity of data on the level of treatment needed to inactivate viruses in the wash water, which is critical for preventing cross-contamination. The objective of this study was to quantify the susceptibility of hNoV genotype I (GI), hNoV GII, murine norovirus (MNV), and bacteriophage MS2 to free chlorine in whole leaf, chopped romaine, and shredded iceberg lettuce industrial leafy green wash waters, each sampled three times over a 4-month period. A suite of kinetic inactivation models was fit to the viral reduction data to aid in quantification of concentration-time (CT) values. Results indicate that 3-log infectivity reduction was achieved at CT values of less than 0.2 mg · min/liter for MNV and 2.5 mg · min/liter for MS2 in all wash water types. CT values for 2-log molecular reduction of hNoV GI in whole leaf and chopped romaine wash waters were 1.5 and 0.9 mg · min/liter, respectively. For hNoV GII, CT values were 13.0 and 7.5 mg · min/liter, respectively. In shredded iceberg wash water, 3-log molecular reduction was not observed for any virus over the time course of experiments. These findings demonstrate that noroviruses may exhibit genogroup-dependent resistance to free chlorine and emphasize the importance of distinguishing between genogroups in hNoV persistence studies. Postharvest washing of millions of pounds of leafy greens is performed daily in industrial processing facilities with the intention of removing dirt, debris, and pathogenic microorganisms prior to packaging. Modest inactivation of pathogenic microorganisms (less than 2 log) is known to occur on the surfaces of leafy greens during washing. Therefore, the primary purpose of the sanitizing agent is to maintain microbial quality of postharvest processing water in order to limit cross-contamination. This study modeled viral inactivation data and quantified the free-chlorine CT values that processing facilities must meet in order to achieve the desired level of hNoV GI and GII reduction. Disinfection experiments were conducted in industrial leafy green wash water collected from a full-scale fresh produce processing facility in the United States, and hNoV GI and GII results were compared with surrogate molecular and infectivity data.

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“…Although fresh-cut produce offers diversification, essential nutrients, and convenience, numerous foodborne diseases related to microbial contamination (typically Escherichia coli O157:H7 and Salmonella spp.) have been reported in these products (Berger et al, 2010; Castro-Ibáñez, Gil, & Allende, 2017; Newell, Koopmans, Verhoef, Duizer, Aidara-Kane, Sprong et al, 2010; Yaron & Römling, 2014). In addition, the decay of fruits and vegetables caused by fungi is responsible for huge economic losses to growers, tradesmen, and consumers.…”

Section: Introductionmentioning

confidence: 91%

“…Chemical sanitizers have been widely used in minimal processing industries owing to their advantages of efficacy and low cost (Meireles, Giaouris, & Simões, 2016), such as chlorine, organic acid, ozone, hydrogen peroxide, sodium hypochlorite, and quaternary ammonium compounds (Castro-Ibáñez, Gil, & Allende, 2017; Ma, Zhang, Bhandari, & Gao, 2017; Ramos, Miller, Brandão, Teixeira, & Silva, 2013). However, chlorine-based agents are ineffective against some microorganisms and can lead to the generation of carcinogenic compounds (Glowacz, Colgan, & Rees, 2015).…”

Section: Introductionmentioning

confidence: 99%

Comparison of Generally Recognized as Safe Organic Acids for Disinfecting Fresh-cut Lettuce

Wang

Tao

Liu

et al. 2018

Preprint

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14In this study, we aimed to determine the organic acids (acetic, lactic, citric, malic, 15 propionic, succinic, and tartaric acids; 1% and 0.5%, w/w or v/v) that were most 16 effective for fresh-cut lettuce disinfection based on analysis of quality (i.e., color, 17 electrolyte leakage, and sensory quality) and microbial examination. The results 18 showed that these acids did not negatively affect the color quality (i.e., L * , a * , b * , 19 whiteness index, and sensory color). Additionally, 0.5% lactic acid led to the lowest 20 electrolyte leakage (0.83%), which was not significantly different (p > 0.05) from that 21 of distilled water (0.46%). Lactic acid (1%) did not affect the sensory quality and led 22 to the highest microbial reduction (1.45 log reduction in aerobic plate counts [APCs]; 23 2.31 log reduction in molds and yeasts [M&Y]) and was therefore recommended as 24 the primary choice for lettuce disinfection. Malic acid (0.5%), with a 1.07% 25 electrolyte leakage rate, 0.73 log reduction in APCs, and 1.40 log reduction in M&Y, 26 was better than the other six acids (0.5%) and was recommended as a pH regulator 27 and a potential synergistic agent for oxidizing sanitizers. Acetic acid (1%) negatively 28 affected the sensory quality and led to the highest electrolyte leakage (2.90%). 29Microbial analysis showed that propionic acid (0.5% and 1%) was ineffective for 30 disinfection of lettuce (p > 0.05); thus, acetic and propionic acids were not 31 recommended. Our results provide insights into the choice of sanitizers and formula 32 design in food safety. 33 IMPORTANCE 34Since chlorine is forbidden in several countries, generally recognized as safe 35 organic acids are used in minimal processing industries and in household sanitizers. 36The disinfection efficacy of organic acids has been studied when used alone or with 37 oxidizing sanitizers. However, since different antibacterial mechanisms, contact time, 38 fresh produce, and concentration have been reported, the acids most effective for 39 single fresh produce disinfection, especially that of lettuce, an important salad 40 vegetable, are not known. Moreover, in developing countries, because of 41 imperfections in field management, cold chain transportation, and minimal processing 42 industry development, the demand for low-cost household sanitizers is greater than 43 that for minimally processed fresh produce. In this work, microbial load in lettuce was 44 determined after disinfecting with seven GRAS organic acids. The changes in quality 45 were also determined. These results provide insights into the choice of minimal 46 processing sanitizers and a formula design for household sanitizers. 47 48

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Ready-to-eat vegetables: Current problems and potential solutions to reduce microbial risk in the production chain

Cited by 114 publications

References 70 publications

Microbial Contamination of Fresh Produce: What, Where, and How?

Microbial Contamination of Fresh Produce: What, Where, and How?

Inactivation of Human Norovirus Genogroups I and II and Surrogates by Free Chlorine in Postharvest Leafy Green Wash Water

Comparison of Generally Recognized as Safe Organic Acids for Disinfecting Fresh-cut Lettuce

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