Growth inhibitory effects of Adhatoda vasica and its potential at reducing Listeria monocytogenes in chicken meat

The inhibitory effects of Adhatoda vasica ethanolic leaf extract (AVELE) against Listeria monocytogenes were examined to assess its potential to preserve minimally processed meat products safely. The total phenolic, flavonoid, and alkaloid levels in AVELE were 10.09 ± 4.52 mg of gallic acid equivalents (GAE)/g, 22.43 ± 1.62 mg of quercetin equivalents/g, and 19.43 ± 3.90 mg/g, respectively. AVELE (1, 5, 10, or 20%) had considerable antibacterial effects against L. monocytogenes NCIM 24563 in terms of the inhibitory zones (7.4-13.6 mm), MIC (100 mg/mL or 10% formulated solution), reduced cell viability, potassium ion efflux, and the release of 260-nm absorbing materials and extracellular ATP. AVELE was used as a rinse solution (5, 10, and 20%) for raw chicken breast meat. A 20% rinsing solution applied for 60 min inhibited the L. monocytogenes NCIM 24563 counts significantly on raw chicken breast meat. Moreover, L. monocytogenes NCIM 24563 did not grow in the meat sample when the rinse time was increased to 90 min at the same concentration. L. monocytogenes showed a greater reduction to ~3 CFU/g after rinsing with a 10 and 20% AVELE solution for 30 min than with a 5% AVELE solution. The rinsing processes with AVELE produced the final cooked chicken products with higher sensory attribute scores, such as taste, juiciness, and tenderness, compared to the control group along with a decrease in microbial contamination. Chicken meat rinsed with AVELE (rinsing time of 90 min) showed better sensory attribute scores of juiciness and tenderness, as well as the overall sensory quality compared to the untreated group. This research highlights the effectiveness of AVELE against L. monocytogenes NCIM 24563, suggesting that AVELE can be used as an effective antimicrobial marinade and/or a rinse for meat preservation.