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Food Microbiol. 2017 Sep;66:55-63. doi: 10.1016/j.fm.2017.04.003. Epub 2017 Apr 6.

High relative humidity pre-harvest reduces post-harvest proliferation of Salmonella in tomatoes.

Author information

1
Department of Public Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium; Emerging Pathogens Institute, Institute for Sustainable Food Systems and Department of Animal Sciences, University of Florida, Gainesville, FL, USA. Electronic address: brechtdv@gmail.com.
2
Department of Natural Science, Middlesex University London, London, UK; Soil and Water Science Department, Genetics Institute, University of Florida-Institute of Food and Agricultural Sciences (IFAS), Gainesville, FL, USA.
3
Department of Public Health Sciences, University of Chicago, IL, USA.
4
Soil and Water Science Department, Genetics Institute, University of Florida-Institute of Food and Agricultural Sciences (IFAS), Gainesville, FL, USA.
5
Institute of Health and Society (IRSS), Université catholique de Louvain, Brussels, Belgium.
6
Emerging Pathogens Institute, Institute for Sustainable Food Systems and Department of Animal Sciences, University of Florida, Gainesville, FL, USA.

Abstract

Outbreaks of human illness caused by enteric pathogens such as Salmonella are increasingly linked to the consumption of fruits and vegetables. Knowledge on the factors affecting Salmonella proliferation on fresh produce therefore becomes increasingly important to safeguard public health. Previous experiments showed a limited impact of pre-harvest production practices on Salmonella proliferation on tomatoes, but suggested a significant effect of harvest time. We explored the data from two previously published and one unpublished experiment using regression trees, which allowed overcoming the interpretational difficulties of classical statistical models with higher order interactions. We assessed the effect of harvest time by explicitly modeling the climatic conditions at harvest time and by performing confirmatory laboratory experiments. Across all datasets, regression trees confirmed the dominant effect of harvest time on Salmonella proliferation, with humidity-related factors emerging as the most important underlying climatic factors. High relative humidity the week prior to harvest was consistently associated with lower Salmonella proliferation. A controlled lab experiment confirmed that tomatoes containing their native epimicrobiota supported significantly lower Salmonella proliferation when incubated at higher humidity prior to inoculation. The complex interactions between environmental conditions and the native microbiota of the tomato crop remain to be fully understood.

KEYWORDS:

Climate; Food safety; Human pathogens; Plant-pathogen interactions; Produce

PMID:
28576373
DOI:
10.1016/j.fm.2017.04.003
[Indexed for MEDLINE]

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