Effect of liquid smoke as an ingredient in frankfurters on Listeria monocytogenes and quality attributes.

Market trends indicate an increased interest in natural antimicrobials to augment safety of ready-to-eat meat and poultry products against Listeria monocytogenes. Liquid smoke, an all-natural condensate of smoke components, applied as a postprocess treatment on product surface has the potential to exhibit antilisterial properties. Studies on its antimicrobial efficacy and quality attributes as an ingredient are not sufficient. A study was designed to validate the antimicrobial effect of liquid smoke as an ingredient against L. monocytogenes and its effect on the shelf life and quality of frankfurters. Chicken/pork frankfurters were incorporated with 0, 2.5, 5, and 10% liquid smoke (Zesti Smoke, Kerry Ingredients and Flavors, TN). Cooked casing-stripped frankfurters (4 per package) were placed in vacuum-pack bags, spray inoculated with either high (8 log(10) cfu/ mL) or low (4 log(10) cfu/ mL) levels of L. monocytogenes serotype 4b, vacuum packaged, and stored at 4°C for up to 12 wk. Samples were taken every week for 12 wk to estimate growth of L. monocytogenes and spoilage microflora (aerobic plate counts, yeast and molds, lactic acid bacteria, and total coliforms) and properties of sensory scores and texture profile analysis. The experiment was conducted as 3 separate trials and data was analyzed to find significant differences at P < 0.05. Formulation of frankfurters with smoke extract at 2.5, 5, and 10% reduced (P < 0.05) populations of L. monocytogenes as compared with the controls throughout the storage period irrespective of the inoculation levels. Furthermore, incorporation of smoke extract did not affect (P > 0.05) the texture, juiciness, flavor, and overall scores as well as hardness and chewiness of the frankfurters. Zesti Smoke can be effectively incorporated as an all-natural antimicrobial in the manufacture of frankfurters without negatively affecting quality attributes.