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Shang H, Tan BZ, Dakwa V, D'Agnese E, Stanley RA, Sassi H, Lai YW, Deaker R, Bowman JP. Effect of pre-harvest sanitizer treatments on Listeria survival, sensory quality and bacterial community dynamics on leafy green vegetables grown under commercial conditions. Food Res Int 2023; 173:113341. [PMID: 37803650 DOI: 10.1016/j.foodres.2023.113341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 07/19/2023] [Accepted: 07/31/2023] [Indexed: 10/08/2023]
Abstract
Leafy green vegetables (LGVs) have large surface areas and can be colonized by various microorganisms including pathogens. In this study, we investigated the effect of pre-harvest sanitizer treatments on the survival of inoculated proxy pathogen Listeria innocua ATCC 33090 and the natural microbial community of mizuna, rocket (arugula), red chard and spinach grown under commercial conditions. Electrolyzed water (e-water), peracetic acid (PAA), and 1-bromo-3-chloro-5-dimethylhydantoin (BCDMH) were tested against water controls. We also observed the subsequent sensorial changes of harvested, bagged LGV leaves over a period of 12 days within chill storage alongside the growth, diversity and structure of bacterial populations determined using 16S rRNA gene amplicon sequencing and total viable counts (TVC). Treatment with PAA resulted in the highest reductions of L. innocua (2.4-5.5 log units) compared to the other treatments (0.25-2.5 log units). On day 0 (24 h after sanitizer application), the TVC on sanitizer treated LGVs were significantly reduced compared to water controls, except for rocket. During storage at 4.5 (±0.5)°C sanitisers only hindered microbial growth on LGVs initially and did not influence final bacterial population levels, growth rates or changes in LGV sample colour, decay, odour and texture compared to water controls. Shelf-life was not extended nor was it reduced. The community structure on LGV types differed though a core set of bacterial amplicon sequence variants (ASV) were present across all samples. No significant differences were observed in bacterial diversity between sanitizer treatments, however sanitizer treated LGV samples had initially reduced diversity compared to water treated samples. The bacterial compositions observed at the end point of storage considerably differed from what was observed at initial point owing to the increase in abundance of specific bacterial taxa, mainly Pseudomonas spp., the abundance and growth responses differing between LGV types studied. This study provides a better understanding on the microbiology and sensory impact of pre-harvest applied sanitiser treatments on different LGVs destined for commercial food use.
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Affiliation(s)
- Hongshan Shang
- School of Life and Environmental Sciences, F22 - LEES Building, The University of Sydney, NSW 2006, Australia; Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia
| | - Bi Zheng Tan
- Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia
| | - Vongai Dakwa
- Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia
| | - Erin D'Agnese
- Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia
| | - Roger A Stanley
- Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia
| | - Hannah Sassi
- School of Life and Environmental Sciences, F22 - LEES Building, The University of Sydney, NSW 2006, Australia
| | - Yu-Wen Lai
- School of Life and Environmental Sciences, F22 - LEES Building, The University of Sydney, NSW 2006, Australia
| | - Rosalind Deaker
- School of Life and Environmental Sciences, F22 - LEES Building, The University of Sydney, NSW 2006, Australia
| | - John P Bowman
- Centre for Food Safety and Innovation, Tasmanian Institute of Agriculture, University of Tasmania, Sandy Bay, Tasmania 7005, Australia.
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Marçal S, Campos DA, Pintado M. Washing with sodium hypochlorite or peracetic acid: Its impact on microbiological quality, phytochemical composition and antioxidant activity of mango peels. Food Control 2022. [DOI: 10.1016/j.foodcont.2022.109080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Bacterial Diversity and Dominant Spoilage Microorganisms in Fresh-Cut Broccoli. APPLIED SCIENCES-BASEL 2022. [DOI: 10.3390/app12073370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Different cutting types not only affect the quality and bioactive substances of broccoli but may produce wounding stress that influences the quantity and diversity of microorganisms and finally leads to safety concerns. In this study, three different fresh-cutting types (floret (F), quarterly cut floret (QF) and shredded floret (FS)) and four storage stages (0, 1, 2 and 3 day(s)) were designed to detect the bacterial diversity in broccoli. Results showed that the quantity and growth of microorganisms in fresh-cut broccoli were positively correlated with the intensity of fresh-cut damage, and the 97 strains isolated using 16S rRNA gene sequences were mainly classified into four phyla: Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes. The predominant phylum was Proteobacteria, dominated by Pseudomonas spp. and Acinetobacter spp. Four representative strains of different species were selected to analyze their spoilage potential on fresh-cut broccoli. Pseudomonas spp. had great impacts on the corruption of broccoli, which affected fresh-cut broccoli by metabolizing to produce nitrite and consuming nutrition. Moreover, Comamonas spp. and Acinetobacter spp. also affected the quality of broccoli, but received little attention previously. This study provides a reference for precise bacteriostasis and preservation of fresh-cut vegetables such as broccoli.
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