Risk of Human Pathogen Internalization in Leafy Vegetables During Lab-Scale Hydroponic Cultivation

Gina Riggio,Sarah Jones,Kristen Gibson

doi:10.3390/horticulturae5010025

Gina Riggio, Sarah Jones + Show 1 more

Open Access

https://doi.org/10.3390/horticulturae5010025

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Journal: Horticulturae	Publication Date: Mar 15, 2019
Citations: 49	License type: CC BY 4.0

Affiliation: University of Arkansas at Fayetteville

Abstract

Controlled environment agriculture (CEA) is a growing industry for the production of leafy vegetables and fresh produce in general. Moreover, CEA is a potentially desirable alternative production system, as well as a risk management solution for the food safety challenges within the fresh produce industry. Here, we will focus on hydroponic leafy vegetable production (including lettuce, spinach, microgreens, and herbs), which can be categorized into six types: (1) nutrient film technique (NFT), (2) deep water raft culture (DWC), (3) flood and drain, (4) continuous drip systems, (5) the wick method, and (6) aeroponics. The first five are the most commonly used in the production of leafy vegetables. Each of these systems may confer different risks and advantages in the production of leafy vegetables. This review aims to (i) address the differences in current hydroponic system designs with respect to human pathogen internalization risk, and (ii) identify the preventive control points for reducing risks related to pathogen contamination in leafy greens and related fresh produce products.

Highlights

In 2018, the United States (U.S.) fresh produce industry was implicated in three separate multi-state outbreaks linked to contaminated field-grown romaine lettuce from Arizona and California, which produce 94.7% of the leafy greens in the U.S [1]
The authors concluded that these results suggest that E. coli O157:H7 internalization is dependent on root damage and not the growth medium, which could be linked to (1) root damage in soil or (2) increased plant defenses in hydroponics where plants were exposed to repeated contamination
This review aimed to highlight the risks associated with human pathogen internalization in leafy vegetables cultivated in lab-scale hydroponic systems

Summary

Introduction

In 2018, the United States (U.S.) fresh produce industry was implicated in three separate multi-state outbreaks linked to contaminated field-grown romaine lettuce from Arizona and California, which produce 94.7% of the leafy greens in the U.S [1]. From 1973 to 2012, leafy greens have comprised more than half of the fresh produce-associated outbreaks reported in the U.S [5]. While risk management strategies and regulatory requirements Rule) were developed in response to produce-associated outbreaks, these are primarily applicable to conventional, field-grown crops as opposed to controlled environment agriculture (CEA). CEA is a growing industry and a potentially desirable alternative production system, as well as a risk management solution for the fresh produce industry. According to a 2017 survey of over 150 farms worldwide, a total of 450,000 square feet of production space was added during a one-year period [6]

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