Gamma radiation treatment of postharvest produce for Salmonella enterica reduction on baby carrot and grape tomato

• Published in: Journal of food safety Vol. 42; no. 1
• Main Authors: Berrios‐Rodriguez, Armarynette, Olanya, Ocen M., Niemira, Brendan A., Ukuku, Dike O., Mukhopadhyay, Sudarsan, Orellana, Lynette E.
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01-02-2022; Blackwell Publishers Inc
• Subjects: Food contamination; Food safety; Gamma rays; Inoculation; Irradiation; Pathogens; Populations; Radiation dosage; Radiation therapy; Salmonella; Salmonella enterica; Temperature effects; Tomatoes; Vegetables; γ Radiation
• ISSN: 0149-6085; 1745-4565
• DOI: 10.1111/jfs.12951

Occurrences and contamination of Salmonella enterica on produce are a significant food safety issue. The objective of this research was to evaluate the effects of low‐dose gamma radiation on survival and reductions of S. enterica on postharvest carrot and tomato. Irradiation treatments of 0–1 kGy were applied on produce, following pathogen inoculations in replicated experiments. The effects of temperatures (5 and 20°C) and storage times (0, 3, and 7 days) on pathogen reductions were determined. The mean Salmonella populations in untreated control produce varied from 7.12 ± 0.05 to 7.54 ± 0.12 log Cfu/g of produce. Pathogen reductions by gamma radiation were significant (p < .05) and varied with storage times (0–7 days). Salmonella populations were reduced on carrot by 4.3 logs (5°C) and 3.7 logs (20°C) at 1 kGy treatment. On tomato, pathogen reductions at 1 kGy did not differ significantly (p > .05) and were 5.6 and 5.8 logs at 5 and 20°C, respectively. Linear decreases in Salmonella populations occurred as radiation dosage increased. Injury of bacterial cells from radiation treatment was comparatively greater at 1 kGy than other treatments. Low‐dose gamma radiation treatment resulted in significant Salmonella reductions on produce and enhanced postharvest safety of carrot and tomato.
Gamma radiation (0.25–1 kGy) significantly reduced Salmonella populations on carrot and tomato.
Salmonella reductions and linear decreases occurred as radiation dosage increased.
At 1 kGy treatment, Salmonella reductions on carrot at 5 and 20°C were 4.3 and 3.7 logs. On tomato, pathogen reductions at 5 and 20°C were 5.6 and 5.8 logs, respectively.
The lowest radiation treatment that achieved bacterial inactivation was documented.
Injury of Salmonella cells from irradiated produce was greater at 1 kGy with generally low recovery (%) of injured cells.
Low‐dose radiation treatment of produce resulted in significant Salmonella reductions and enhanced postharvest safety of baby carrot and grape tomato.