Effect of adding essential oils of coriander (Coriandrum sativum L.) and hyssop (Hyssopus officinalis L.) on the shelf life of ground beef.

This study examined the effect of adding essential oils of hyssop and coriander at the highest concentration (0.02% v/w) sensorially acceptable to a panel of assessors on the microbiological and biochemical characteristics of stored ground beef. Vacuum-packed meat was stored at 0.5±0.5°C and 6±1°C for 15days. The greatest beneficial effect of both additives was in inhibiting the development of undesirable sensory changes (extending acceptability by up to 3days) and the growth of Enterobacteriaceae (by up to approximately 1-2 log cycles compared with the controls). The effect on lactic acid bacteria, total viable bacterial count and other groups of microorganisms investigated was minor (up to 1 log cycle) and similar for both oils. Neither did these additives significantly affect amino nitrogen levels, protease activity, the proportions of meat pigments, protein electropherograms and pH levels. This indicates the limited effect of these essential oils in the concentrations applied on preserving vacuum-packed minced beef.