Effect of gamma radiation on the reduction of Salmonella strains, Listeria monocytogenes, and Shiga toxin-producing Escherichia coli and sensory evaluation of minimally processed spinach (Tetragonia expansa)

J Food Prot. 2014 Oct;77(10):1768-72. doi: 10.4315/0362-028X.JFP-14-108.

Abstract

This study evaluated the effects of irradiation on the reduction of Shiga toxin-producing Escherichia coli (STEC), Salmonella strains, and Listeria monocytogenes, as well as on the sensory characteristics of minimally processed spinach. Spinach samples were inoculated with a cocktail of three strains each of STEC, Salmonella strains, and L. monocytogenes, separately, and were exposed to gamma radiation doses of 0, 0.2, 0.4, 0.6, 0.8, and 1.0 kGy. Samples that were exposed to 0.0, 1.0, and 1.5 kGy and kept under refrigeration (4°C) for 12 days were submitted to sensory analysis. D10 -values ranged from 0.19 to 0.20 kGy for Salmonella and from 0.20 to 0.21 for L. monocytogenes; for STEC, the value was 0.17 kGy. Spinach showed good acceptability, even after exposure to 1.5 kGy. Because gamma radiation reduced the selected pathogens without causing significant changes in the quality of spinach leaves, it may be a useful method to improve safety in the fresh produce industry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aizoaceae / microbiology*
  • Colony Count, Microbial
  • Dose-Response Relationship, Radiation
  • Food Irradiation / methods*
  • Food Microbiology
  • Food Preservation / methods
  • Gamma Rays*
  • Listeria monocytogenes / radiation effects*
  • Refrigeration
  • Salmonella / radiation effects*
  • Shiga-Toxigenic Escherichia coli / radiation effects*
  • Temperature