Effects of Plant Age and Root Damage on Internalization of Shiga Toxin-Producing Escherichia coli in Leafy Vegetables and Herbs
Open Access
- 2 April 2021
- journal article
- research article
- Published by MDPI AG in Horticulturae
- Vol. 7 (4), 68
- https://doi.org/10.3390/horticulturae7040068
Abstract
Our previous study reported that fresh produce grown in aquaponic and hydroponic systems can pose potential food safety hazards due to an accidental introduction of contaminated fish and cross-contamination between the systems. In this study, we examined the effects of plant species and age on the likelihood and level of internalization of Shiga toxin-producing Escherichia coli (STEC) in aquaponic and hydroponic systems. Four plant species, basil (Ocimum basilicum L. cv. Genovese), cilantro (Coriandrum Sativum L.), lettuce (Lactuca sativa cv. Cherokee), and kale (Brassica oleracea var. sabellica), received root damage treatment as seedlings before transplanting or mature plants at three weeks after transplanting by cutting off 1-cm tips of one-third of the roots. Enrichments and selective media were used for the isolation, and presumptive positive colonies were confirmed by PCR for the presence of stx1 gene in plant tissues, recirculating water, and fish feces collected at four weeks after transplanting. In hydroponic systems, STEC was found neither in the solution nor in the roots and leaves of all four plant species, possibly through improved sanitation and hygiene practices. However, consistent with our previous findings, STEC was found in the water, on the plant roots, and in the fish feces in aquaponic systems, even after thorough sanitation prior to the study. Regardless of plant age, STEC was internalized in the roots of all plant species when the roots were damaged, but there was no difference in the degree of internalization with STEC among plant species. STEC was present in the leaves only when seedlings received root damage treatment and were grown to maturity, indicating that root damage allows STEC to internalize in the roots within a week, but a longer period is required for STEC to internalize into the leaves. We concluded that root damage on seedlings can cause the internalization of E. coli O157:H7 in the edible parts of leafy vegetables and herbs in soilless production systems.Keywords
Funding Information
- Indiana State Department of Agriculture (ISDA) Specialty Crop Block Grant (SCBG-19-005)
This publication has 55 references indexed in Scilit:
- The Endophytic Lifestyle of Escherichia coli O157:H7: Quantification and Internal Localization in RootsPhytopathology®, 2013
- Attribution of Foodborne Illnesses, Hospitalizations, and Deaths to Food Commodities by using Outbreak Data, United States, 1998–2008Emerging Infectious Diseases, 2013
- Internalization of E. coli O157:H7 and Salmonella spp. in plants: A reviewFood Research International, 2012
- Climate change and food safety: A reviewFood Research International, 2010
- Survival of Escherichia coli in the environment: fundamental and public health aspectsThe ISME Journal, 2010
- Interactions of Escherichia coli O157:H7, Salmonella typhimurium and Listeria monocytogenes plants cultivated in a gnotobiotic systemInternational Journal of Food Microbiology, 2005
- Direct PCR detection of Escherichia coli O157:H7Letters in Applied Microbiology, 2003
- Pathogen Survival in Swine Manure Environments and Transmission of Human Enteric Illness—A ReviewJournal of Environmental Quality, 2003
- Effects of inoculum density, plant age and temperature on disease severity caused by pythiaceous fungi on several plantsPhytoparasitica, 2002
- Sterilization of Plants for Phytoremediation Studies by Bleach TreatmentInternational Journal of Phytoremediation, 2000