A Cranberry Extract as a Marinade Inhibits Growth of Listeria on Chicken

Introduction: Cranberry extracts, natural, plant-based products, have been shown to inhibit foodborne pathogens as well as spoilage organisms in vitro. Our previous studies have also demonstrated microbial susceptibility to cranberry extracts in broth and liquid food systems.

Purpose: The goal of this study was to expand the applications of a cranberry extract as natural antimicrobial on a solid food system.

Methods:  L. innocua was used as a surrogate for L. monocytogenes. Unprocessed chicken slices were inoculated with L. innocua and air-dried prior to exposure to cranberry-based marinades. Untreated but inoculated chicken, as well as water-treated chicken slices were included as controls. At 30 minutes and 3 hours post treatment under refrigeration, samples were enumerated for L. innocua. Each experiment was carried out in triplicate. Student’s t-test was used for statistical analysis of the efficacy of microbial growth inhibition.

Results:  Exposure to a marinade containing cranberry extract significantly resulted in a 2-log reduction (P < 0.05) of L. innocua on chicken slices with 3 hours post-exposure. A 30-minute exposure resulted in a 1-log reduction of Listeria on chicken.

Significance: Cranberry-derived products provide attractive alternatives to existing naturally occurring antimicrobials in food systems. The findings of this study showed that a cranberry extract could have widespread use to control Listeria sp. on unprocessed meat and poultry products.