The effect of acid marinades on Listeria monocytogenes, shelf-life, meat quality, and consumer acceptability of beef frankfurters

Abstract

The USDA-FSIS requires processors producing ready-to-eat (RTE) meat and poultry products exposed to the environment after the primary lethality step to employ alternatives to kill or inhibit the growth of Listeria monocytogenes (LM). Acid marinades are in use as LM inhibitors, pH controllers, humectants and flavor enhancers. However, these acid marinades have the potential to negatively affect product quality and consumer acceptability. Acid marinades: (i) control (no marinade addition) (C); (ii) sodium lactate (2%; wt/wt) (SL); (iii) potassium lactate (2%; wt/wt) (PL); (iv) sodium citrate (0.75%; wt/wt) (SC); and (v) sodium lactate (2%; wt/wt)/sodium diacetate (0.25%; wt/wt) (SLSD) were incorporated into beef frankfurters. Untrained sensory panels evaluated treatments (8-point Hedonic scale) weekly for 12 weeks. Beef frankfurters were inoculated (107 log CFU/mL) with a streptomycin-resistant (1500μg/mL) strain of LM known to be pathogenic to humans and stored at 4°C. Samples were enumerated weekly for, aerobic plate count, psychrotrophs, and LM. SL, PL, and SC treatments did not adversely affect consumer acceptability through 12 weeks although, SL/SD treatment was significantly (P < 0.05) less preferential across all sensory attributes. SL/SD treatment negatively affected product quality, but was able to control APC, PSY, and LM levels. SC performed similarly to the control throughout the 8, 9, and 10 week storage periods, providing no benefit for inhibiting LM or extending shelf-life of the beef frankfurters. In conclusion, 2% SL, 2% PL, and 2% SL/0.25% SD may be effective LM inhibitors, but changes in SL/SD treatment formulation should be studied to increase product quality.