Use of Rhodomyrtus tomentosa ethanolic leaf extract for the bio-control of Listeria monocytogenes post-cooking contamination in cooked chicken meat.

Abstract

Controlling foodborne pathogen in ready-to-eat food is important in food safety. The present study accessed the potential use of Rhodomyrtus tomentosa ethanolic leaf extract as a bio-control agent against Listeria monocytogenes in cooked chicken meat model system. The antilisterial activity of the plant extract was better under microwave condition and enhanced as storage temperature increased from 4 to 37°C. The extract could reduce L. monocytogenes numbers at low (104CFU/g) and high (106CFU/g) inoculum levels in cooked chicken by both rinse and injection application methods. A 5min rinse in 8% w/v R. tomentosa extract reduced the bacterial number by ≥2-log before storage and ≥3-log after storage at 4°C for 5days. Injection with 0.4% w/w R. tomentosa extract resulted in approximately 2-log reduction in the cell numbers both before and after storage at 4°C for 5days. Five minutes rinse in the extract bath demonstrated better sensory preferences which were not significantly different from the control. Addition of black pepper powder to the extract rinsed samples improved odour but not appearance, colour, and texture preferences. Rhodomyrtus tomentosa extract was significantly effective for the bio-control of L. monocytogenes contaminations in cooked chicken meat model. The extract was observed as a potent bio-additive agent to control contaminations from L. monocytogenes and ensure safety in ready-to-eat meat.