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Cha MY, Ha JW. Low-energy X-ray irradiation effectively inactivates major foodborne pathogen biofilms on various food contact surfaces. Food Microbiol 2022; 106:104054. [DOI: 10.1016/j.fm.2022.104054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 11/04/2022]
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Lim JS, Ha JW. Growth temperature influences the resistance of Escherichia coli O157:H7 and Salmonella enterica serovar Typhimurium on lettuce to X-ray irradiation. Food Microbiol 2021; 99:103825. [PMID: 34119110 DOI: 10.1016/j.fm.2021.103825] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 01/22/2023]
Abstract
This study aimed to investigate the effect of different growth temperatures on the resistance of Escherichia coli O157:H7 and Salmonella Typhimurium to low-energy X-ray irradiation. Irradiation of contaminated phosphate-buffered saline with 0.6 kGy X-ray decreased the counts of E. coli O157:H7 cultured at 37 °C to below the detection limit (<1.0 colony-forming unit (CFU)/mL) and those of E. coli O157:H7 cultured at 25 and 15 °C by 4.82 and 4.45 log CFU/mL, respectively. The viable counts of S. Typhimurium cultured at 37, 25, and 15 °C in phosphate-buffered saline decreased by 3.56, 3.08, and 2.75 log CFU/mL, respectively, after irradiation with 0.6 kGy X-ray. Irradiation of contaminated lettuce with 0.4 kGy decreased the counts of E. coli O157:H7 cultured at 37, 25, and 15 °C by 3.97, 3.45, and 3.10 log CFU/cm2, respectively, and those of S. Typhimurium by 4.41, 3.84, and 3.40 log CFU/cm2, respectively. Growth temperature influenced pathogen resistance to X-ray irradiation by modulating cellular membrane and DNA integrity, intracellular enzyme activity, and efflux pump function. The results of this study suggest that the stress resistance status of pathogenic bacteria cultured at different growth temperatures should be considered for the application of X-ray irradiation for fresh produce sterilization.
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Affiliation(s)
- Jong-Seong Lim
- Department of Food Science and Biotechnology, Global K-Food Research Center, Hankyong National University, Anseong-si, 17579, South Korea
| | - Jae-Won Ha
- Department of Food Science and Biotechnology, Global K-Food Research Center, Hankyong National University, Anseong-si, 17579, South Korea.
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Zhang H, Pang X, Seck HL, Zhou W. Low-energy X-ray inactivation of Listeria monocytogenes in mono-/co-culture biofilms with Pseudomonas fluorescens on food contact surfaces. Food Microbiol 2021; 100:103841. [PMID: 34416951 DOI: 10.1016/j.fm.2021.103841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Revised: 05/26/2021] [Accepted: 05/26/2021] [Indexed: 10/21/2022]
Abstract
This study assessed the inactivation kinetics of 150 keV low-energy X-ray on mono-/co-culture biofilms of Listeria monocytogenes and Pseudomonas fluorescens on three different food-contact-surfaces (polyethylene, acrylic, and stainless steel). The results indicated that the level of biofilm formation of mono-/co-cultures of L. monocytogenes and P. fluorescens was the highest on acrylic. The mono-culture L. monocytogenes biofilm cells exhibited higher resistance to the low-energy X-rays than the corresponding mono-culture P. fluorescens biofilm cells, regardless of surface types. Furthermore, co-culture had enhanced the resistance of both P. fluorescens and L. monocytogenes biofilm cells to the low-energy X-ray. Two kinetic models for the inactivation process were investigated, including (i) Linear model and (ii) Weibull model. Based on R2, RMSE and AIC analysis, the Weibull model was superior in fitting the inactivation curves of low-energy X-ray on L. monocytogenes in mono-/co-culture biofilms with P. fluorescens. For mono-culture biofilms, the irradiation achieved the tR1 value (derived from the Weibull model, i.e., the dose required for the first 1-log reduction) of 46.36-50.81 Gy for L. monocytogenes and the tR1 value of 25.61-31.33 Gy for P. fluorescens. For co-culture biofilms, higher tR1 values for L. monocytogenes (59.54-70.77 Gy) and P. fluorescens (32.73-45.13 Gy) were yielded than those for their individual counterparts in mono-culture biofilm.
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Affiliation(s)
- Hongfei Zhang
- Department of Food Science and Technology, National University of Singapore, Science Drive 2, 117542, Singapore
| | - Xinyi Pang
- Department of Food Science and Technology, National University of Singapore, Science Drive 2, 117542, Singapore; College of Food Science and Engineering, Nanjing University of Finance and Economics, Nanjing, 210003, China
| | - Hon Luen Seck
- A*STAR Singapore Institute of Manufacturing Technology, Singapore
| | - Weibiao Zhou
- Department of Food Science and Technology, National University of Singapore, Science Drive 2, 117542, Singapore; National University of Singapore (Suzhou) Research Institute, 377 Linquan Street, Suzhou Industrial Park, Jiangsu, 215123, China.
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Sarraf M, Jemni M, Kahramanoğlu I, Artés F, Shahkoomahally S, Namsi A, Ihtisham M, Brestic M, Mohammadi M, Rastogi A. Commercial techniques for preserving date palm ( Phoenix dactylifera) fruit quality and safety: A review. Saudi J Biol Sci 2021; 28:4408-4420. [PMID: 34354425 PMCID: PMC8324939 DOI: 10.1016/j.sjbs.2021.04.035] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/11/2021] [Accepted: 04/12/2021] [Indexed: 11/16/2022] Open
Abstract
The popularity of date palm (Phoenix dactylifera) fruit is increasing, therefore the demand for high-quality date palm fruit with less or no chemical treatment is the topic of interest for date producers and consumers. The quality of date palm fruit is much dependent on its postharvest handling and processing. For preventing the degradation and maintenance of the high quality of dates during the storage an appropriate harvest and post-harvest processes are required. The process should control the biotic and abiotic factors like insects, fungus, temperature, as well as handling and processing of dates. Therefore, in this work, we reviewed the literature related to the protection of date fruits during their post-harvest life. The commercially viable advance and updated techniques that can be used to avoid storage losses and problems while keeping fruit quality (nutritional, color, flavor, and texture) and microbial safety under optimal conditions are discussed.
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Affiliation(s)
- Mohammad Sarraf
- Department of Horticulture Science, Shiraz Branch, Islamic Azad University, Shiraz 71987-74731, Iran
| | - Monia Jemni
- Regional Research Center in Oasis Agriculture of Degache, Tunisia
| | - Ibrahim Kahramanoğlu
- European University of Lefke, Faculty of Agricultural Sciences and Technologies, Gemikonagi, via Mersin 10, 99780 Northern Cyprus, Turkey
| | - Francisco Artés
- Postharvest and Refrigeration Group, Department of Food Engineering, Universidad Politécnica de Cartagena (UPCT), Paseo Alfonso XIII, Cartagena, Murcia, Spain
- Institute of Plant Biotechnology, UPCT, Campus Muralla del Mar, Cartagena, Murcia, Spain
| | - Shirin Shahkoomahally
- Department of Horticultural Science, University of Florida, Gainesville, FL 32611, USA
| | - Ahmad Namsi
- Regional Research Center in Oasis Agriculture of Degache, Tunisia
| | - Muhammad Ihtisham
- College of Landscape Architecture, Sichuan Agricultural University, Chengdu, Sichuan 611130, China
| | - Marian Brestic
- Department of Plant Physiology, Slovak University of Agriculture, A. Hlinku 2, 949 76 Nitra, Slovakia
| | - Mostafa Mohammadi
- Young Researchers and Elite Club, Bushehr Branch, Islamic Azad University, Bushehr, Iran
| | - Anshu Rastogi
- Laboratory of Bioclimatology, Department of Ecology and Environmental Protection, Poznan University of Life Sciences, Piątkowska 94, 60-649 Poznan, Poland
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Ha TMH, Yong D, Lee EMY, Kumar P, Lee YK, Zhou W. Activation and inactivation of Bacillus pumilus spores by kiloelectron volt X-ray irradiation. PLoS One 2017; 12:e0177571. [PMID: 28493969 PMCID: PMC5426783 DOI: 10.1371/journal.pone.0177571] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 04/28/2017] [Indexed: 11/30/2022] Open
Abstract
In this study, we investigated the inactivation efficacy of endospore-forming bacteria, Bacillus pumilus, irradiated by low-energy X-rays of different beam qualities. The different low-energy X-rays studied had cut-off energies of 50, 100 and 150 keV. Bacillus pumilus spores (in biological indicator strips) were irradiated at step doses between 6.5 to 390 Gy. The resulting bacteria populations were then quantified by a pour plate method. Results showed that X-rays of lower energies were more effective in inactivating bacterial spores. In addition, an increment in bacterial population was observed at doses below 13Gy. We attributed this increase to a radiation-induced activation of bacterial spores. Four kinetic models were then evaluated for their prediction of bacterial spore behavior under irradiation. This included: (i) first-order kinetics model; (ii) Shull model; (iii) Sapru model; and (iv) probabilistic model. From R2 and AIC analyses, we noted that the probabilistic model performed the best, followed by the Sapru model. We highlighted that for simplicity in curve fitting the Sapru model should be used instead of the probabilistic model. A 12-log reduction in bacterial population (corresponding to a sterility assurance level of 10−6 as required in the sterilization of medical devices) was computed to be achievable at doses of 1000, 1600 and 2300 Gy for the three different X-ray cut-off energies respectively. These doses are an order in magnitude lesser than that required in gamma irradiation. This highlights the applicability of cheaper and safer table-top X-ray sources for sterilization application.
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Affiliation(s)
- Thi Mai Hoa Ha
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- * E-mail:
| | - Derrick Yong
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
| | - Elizabeth Mei Yin Lee
- Singapore Institute of Manufacturing Technology, Singapore, Singapore
- School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore, Singapore
| | - Prathab Kumar
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
| | - Yuan Kun Lee
- Department of Microbiology, National University of Singapore, Singapore, Singapore
| | - Weibiao Zhou
- Food Science and Technology Programme, c/o Department of Chemistry, National University of Singapore, Singapore, Singapore
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