Inhibition of Escherichia coli O157:H7 and clostridium sporogenesin spinach packaged in modified atmospheres after treatment combined with chlorine and lactic acid bacteria

Implementation of modified atmospheric packaging (MAP) into retail produce is a less commonly practiced method due to differences among commodities and the potential growth of anaerobes. Pathogens includingEscherichia coliO157:H7 have been responsible for spinach outbreaks across the United States. In this study, hurdles, including those currently used with produce safety, such as MAP and chlorine, were combined with lactic acid bacteria (LAB) to inhibit pathogens. Spinach was coinoculated withE. coliO157:H7 andClostridium sporogenes, a surrogate forC. botulinum, and treated with water or a hurdle that included water, chlorine, and LAB. Spinach from treatments were packaged in air (traditional), oxygen (80% O ₂, 20% CO ₂), or nitrogen (80% N ₂, 20% CO ₂) and stored in a retail display case for 9 d at 4 to 7 °C. The hurdle inhibitedE. coliO157:H7 andC. sporogenescompared to controls with reductions of 1.43 and 1.10 log (P< 0.05), respectively. The nitrogen atmosphere was outperformed by air and oxygen in the reduction ofE. coliO157:H7 (P< 0.05) with a decrease of 0.26 and 0.15 logs. There were no significant differences among the 3 atmospheres onC. sporogenessurvival. Relative to these hurdles, we also chose to evaluate the potential benefits of LAB in pathogen control. The survival of LAB in interventions demonstrates implementation of LAB into produce could control pathogens, without damaging produce or altering organoleptic properties.