Radiation sensitization and postirradiation proliferation of Listeria monocytogenes on ready-to-eat deli meat in the presence of pectin-nisin films

J Food Prot. 2009 Mar;72(3):644-9. doi: 10.4315/0362-028x-72.3.644.

Abstract

In this study, the ability of pectin-nisin films in combination with ionizing radiation to eliminate Listeria monocytogenes and inhibit its postirradiation proliferation was evaluated. Pectin films containing 0.025% nisin were made by extrusion. The surface of a ready-to-eat turkey meat sample was inoculated with L. monocytogenes at 10(6) CFU/cm2 and covered with a piece of pectin-nisin film. The samples were vacuum packaged and irradiated at 0, 1, and 2 kGy. The treated samples were stored at 10 degrees C and withdrawn at 0, 1, 2, 4, and 8 weeks for microbial analysis. Reductions in L. monocytogenes viability of 1.42, 1.56, 2.85, 3.78, and 5.36 log CFU/cm2 were achieved for the treatments of 1 kGy, pectin-nisin film, 2 kGy, 1 kGy plus pectin-nisin film, and 2 kGy plus pectin-nisin film, respectively. The greatest reduction (5.5 log CFU/cm2) was observed at 1 week for the 2 kGy plus pectin-nisin film treatment, suggesting that nisin was further released from the film to the surface of meat samples. Pectin-nisin films used in this study did not prevent but did significantly slow (P < 0.05) the proliferation of the L. monocytogenes cells that survived irradiation during 8 weeks of storage at 10 degrees C. These data indicate the potential use of pectin-nisin films alone or in combination with ionizing radiation for preventing listeriosis due to postprocessing contamination of ready-to-eat meat products.

MeSH terms

  • Animals
  • Colony Count, Microbial
  • Consumer Product Safety
  • Dose-Response Relationship, Radiation
  • Food Irradiation*
  • Food Packaging / methods
  • Food Preservation / methods*
  • Food Preservatives / pharmacology*
  • Gamma Rays
  • Humans
  • Listeria monocytogenes / drug effects
  • Listeria monocytogenes / growth & development
  • Listeria monocytogenes / radiation effects*
  • Meat Products / microbiology*
  • Nisin / pharmacology
  • Pectins / pharmacology
  • Time Factors
  • Turkeys
  • Vacuum

Substances

  • Food Preservatives
  • Nisin
  • Pectins