Inactivation of foodborne pathogens in ready-to-eat salad using UV-C irradiation

Choi

Hortic. Environ. Biotechnol.

2011

Self Cite

The effect of aqueous chlorine dioxide (ClO2) combined with UV-C irradiation on the postharvest quality of cherry tomatoes were examined. Cherry tomatoes were inoculated with Salmonella enterica serotype Typhimurium and Escherichia coli O157:H7, and then treated with 10 mg L -1 ClO2, 5 kJ m -2 UV-C, and a combination of ClO2/UV-C treatment. The populations of S. Typhimurium and E. coli O157:H7 in cherry tomatoes were reduced by 2.53 and 2.26 log CFU/g after treatment with aqueous ClO2, respectively. Treatment with UV-C irradiation also reduced the populations of S. Typhimurium and E. coli O157:H7 by 2.58 and 2.65 log CFU/g, respectively, compared to the control. However, the combined treatment of ClO2/UV-C irradiation completely eliminated the inoculated bacteria during storage. Color measurement indicated that Hunter L, a, and b values were not significantly different among the treatments during storage. Therefore, these results suggest that the combined aqueous ClO2 and UV-C treatment could be useful in improving microbial safety of cherry tomatoes during storage without impairing the quality.Additional key words: E. coli O157:H7, non-thermal treatment, S. Typhimurium, UV-C irradiation Hort. Environ. Biotechnol. 52(5):488-493. 2011.

Section: Research Reportmentioning

confidence: 99%

Section: Research Reportmentioning

confidence: 99%

Effect of aqueous chlorine dioxide and UV-C treatment on the microbial reduction and color of cherry tomatoes

Choi

Hortic. Environ. Biotechnol.

2011

Self Cite

Journal of Food Protection

“…The UV sensitivities of gram-negative pathogens such as E. coli 0157:H7 and Salmonella species me much greater than those of most gram-positive bacteria such as Listeria monocytogenes (31). The UVC radiation doses required for a 90% reduction (dR) value of E. coli 0157:H7 and L. monocytogenes on ready-to-eat salad were determined to be 0.21 and 2.48 J/m2, respectively (8).…”

Section: Discussionmentioning

confidence: 99%

Efficacy of UV, Acidified Sodium Hypochlorite, and Mild Heat for Decontamination of Surface and Infiltrated Escherichia coli O157:H7 on Green Onions and Baby Spinach

Durak

Churey

Worobo

2012

Produce-associated foodborne illnesses outbreaks have highlighted the need for more effective decontamination methods to ensure the safety of fresh produce. The main objective of this study was to evaluate the individual and combined efficacies of germicidal UV light (12.5 to 500 mJ/cm2), acidified sodium hypochlorite (ASC; 10 to 200 ppm), and mild heat (40 to 50°C) for decontaminating green onions and baby spinach infected with Escherichia coli O157:H7. Samples were inoculated by spot and dip inoculation methods to mimic surface and infiltrated E. coli O157:H7 contamination, respectively. In green onions and baby spinach, the individual efficacies of UV, ASC, and mild-heat treatments varied based on the produce type and contamination method. Following analysis of the efficacies of the single treatments, a combined treatment with 125 mJ/cm2 UV and 200 ppm of ASC at 50°C was selected for spot-inoculated green onions, and a combined treatment with 125 mJ/cm2 UV and 200 ppm of ASC at 20°C was selected for spot- and dip-inoculated baby spinach. While a >5-log reduction was achieved with the combination treatment for spot-inoculated green onions with an initial contamination level of 7.2 log CFU per spot, the same treatment reduced E. coli O157:H7 populations below the detection limit (<1 log) on green onions spot inoculated at a lower contamination level (4.3 log CFU per spot). On spot- and dip-inoculated baby spinach, the combined treatment reduced E. coli O157:H7 populations by 2.8 log CFU per spot and 2.6 log CFU/g, respectively. The combined treatment of 500 mJ/cm2 UV and 200 ppm of ASC at 50°C selected for the decontamination of dip-inoculated green onions resulted in a 2.2-log CFU/g reduction. These findings suggest that when foodborne pathogens contaminate produce and subsequently infiltrate, attach to, or become localized into protected areas, the individual or combined applications of UV, ASC, and mild-heat treatments have limited decontamination efficacies on both green onions and baby spinach (<3 log). However, treatments combining UV, ASC, and mild heat could be a promising application for reducing pathogen populations (>5 log) on E. coli O157:H7 surface-contaminated green onions. This study also highlights the importance of developing and optimizing produce-specific decontamination methods to ensure the safety of fresh produce commodities.

“…But this method was inefficient from industrial point of view. A good solution might be the double sides UV irradiation method, which has been proved effective in fresh‐cut fruits and vegetables by many studies (Chun, Kim, & Song, ; Guan, Fan, & Yan, ; Kim et al, ; Song, Choi, & Song, ). However, when applied in fresh‐cut industry, UV light cannot completely eliminate all microorganisms and consequently, survivors would grow during storage because the lack of antibacterial agents after irradiation.…”

Section: Introductionmentioning

confidence: 99%

Combined treatment of ultraviolet-C and L. plantarum on Salmonella enteritidis and quality control of fresh-cut apple

Chen

Luo

et al. 2017

J Food Process Preserv

Outbreaks of foodborne illnesses are big problems associated with the consumption of fresh-cut fruits and vegetables. To enhance the safety of fresh-cut apples, this study combined ultraviolet (UV) irradiation and lactic acid bacteria (LAB) to eliminate and inhibit the growth of Salmonella enteritidis on fresh-cut apples. The results showed that the combination treatment of 0.96 kJ/m 2 UV-C irradiation and subsequently dipping in about 5 log CFU/mL LAB suspension could reduce the population of Salmonella enteritidis by 2.67 6 0.13 log CFU/g, which was about 2 log more reduction than distilled water treatment (the reduction was 0.36 6 0.28 log CFU/g). During storage, Salmonella enteritidis remained stable in the combination treatment group while increased up to 5 log CFU/g in the control group. For the quality impact, the combination treatment did not decrease the color, firmness, and flavor of fresh-cut apples but slightly deteriorated the taste attributes. Practical applicationsThe markets of fresh-cut fruits and vegetables have increased rapidly during recent decades. However, the rise of consumption of fresh-cut fruits and vegetables also increases outbreaks of foodborne illnesses. For the health concerns of chlorine, a commonly used disinfectant, healthier, and efficient methods should to be invented to replace the chlorine treatment. Ultraviolet (UV) light possesses high bactericidal ability and lactic acid bacteria (LAB) can inhibit the growth of other microorganisms during storage. The combination can significantly decrease and inhibit other microorganisms before and during storage. It has a promising prospect to be applied in the freshcut industry.