Synergistic Effects of Medicinal Plant Extracts and Lactobacillus Species against Bacterial Pathogens from Smoked Fish and Chicken

An In Vitro Study

Abstract

The rising threat of antibiotic-resistant bacterial pathogens in smoked fish and chicken necessitates exploring alternative natural approaches to control these pathogens. Combining medicinal plant extracts with probiotics may offer a synergistic solution. This study investigates the synergistic effect of medicinal plant extracts and lactobacillus species against bacterial pathogens isolated from smoked fish and chicken providing insights for improving food safety and reducing antibiotic resistance. A total of 280 samples that comprises 40 samples each of native chicken meat, layers chicken meat, broiler chicken meat, Chupea havengus (Herring/sawa), Truchurus trachurus (Horse Mackerel/Kote), Scomber Scombrus (Atlantic Mackerel/Titus) and Sphyraema barracuda (panla). The synergistic effect of some selected medicinal plants and Lactobacillus species was carried out using the agar-welled diffusion method after combining the biological agents at different concentrations. The data obtained were analyzed using a one-way analysis of variance (ANOVA) and turkey’s test as post hoc analysis. The plant extracts; piper guineense  (PU),  Ocimum gratissimum  (OR) and Gongronema latifolium  (GA) which contained alkaloids, tannins, phenolics, saponins, flavonoid, glycosides and steroids, and Lactobacillus species; L. acidophilus strain NC56 (LAN56) and L. plantarum stain 2359 (LP2359) significantly (p≤0.05) inhibited Escherichia coli 0157:H7 strain ECP19-598 (ECEC1), staphylococcus aureus strain JP18269 (SAJP1), Listeria monocytogenes strain LM16 (LMLM1) and Salmonella enterica serovar Enteritidis EC20110358 (SEEC2) isolated from the studied samples. The diameter zones of inhibition significantly (p≤0.05) increased when the biological agents were combined in different doses, and OR+PU+GU and LAN56 + LP2359 combined in 2:1:1 and 2:1 respectively recorded the highest diameter zones of inhibition. Therefore, the medicinal plant extracts and Lactobacillus species combined in their optimal doses showed the highest inhibition against ECEC1, SAJP1, LMLM1 and SEEC2 isolated from smoked fish and chicken meat.