Inhibition of Listeria monocytogenes by Buffered Dry Vinegar in Reduced-Sodium Ready-to-Eat Uncured Turkey Stored at 4°C.

A reduced-sodium ready-to-eat (RTE) uncured turkey was manufactured with buffered dry vinegar treatments to validate the inhibition of Listeria monocytogenes and spoilage microflora and to determine the effects on sensory and quality attributes. Samples were stored at 4°C for 12 weeks, and the study was independently replicated three times. Two different five-strain inocula of L. monocytogenes obtained from different sources were used for evaluating the efficacy of the buffered dry vinegar treatments. The results showed that 0.6 and 0.8% buffered dry vinegar with a sodium base (BDV-SB) and buffered dry vinegar with a potassium base (BDV-PB) at 0.7 and 0.9% controlled L. monocytogenes for 12 weeks. The untreated control product containing no buffered dry vinegar showed >1 log increase in L. monocytogenes populations counts at the end of 2 weeks. Statistical analysis confirmed that the dry vinegar treatments inhibited (P > 0.05) the growth of L. monocytogenes compared with the untreated control. No significant differences (P > 0.05) were seen in the inhibition of L. monocytogenes between the two different five-strain inocula. Instrumental color results showed no significant differences between the treatments. Purge loss results showed no significant differences between the dry vinegar treatments, but significant differences were seen between the untreated control and dry vinegar treatments at a few testing intervals. The overall results indicated that the dry vinegar ingredients (6.66 to 8.83 mM acetic acid in the finished product) were effective in inhibiting L. monocytogenes obtained from multiple sources in reduced-sodium RTE uncured turkey stored at 4°C without adversely impacting the quality attributes.

Antioxidant activities from different rosemary clonal lines.

Rosemary extract is widely used in food industry and carnosic acid is reported to be the major component that is responsible for its antioxidant activities. However, it is unclear how the numerous plant metabolites interact and contribute to the overall antioxidant activity. In this study, with poultry fat as the model food system, rosemary extract from six clonal lines were evaluated that each represented a different genetic variant. As expected, rosemary extract with higher carnosic acid content had higher antioxidant activity. However, rosemary extract which had carnosic acid removed retained a significant amount of activity. Furthermore, when the individual contributions of carnosic acid and the portion without carnosic acid were evaluated separately, neither was shown to be responsible for the overall level of its stabilization effect from rosemary extract as a whole entity. The interactions among different plant metabolites have a major impact on the overall antioxidant capabilities of rosemary extract.