Impact of rosemary (Rosmarinus officinalis) and thyme (Thymus satureioides) essential oils on the physicochemical, microbiological and sensory properties of Merguez sausage during the fermentation process

Aims: This study was aimed to investigate the potential of rosemary (Rosmarinus officinalis) and thyme (Thymus satureioides) essential oils (EOs) in enhancing the safety and stability of Merguez sausages during fermentation.Methodology and results: Initially, the in vitro antibacterial activities of these EOs were evaluated against various pathogens.Subsequently, the impact of two concentrations of EOs (1 and 2%) on the microbiological (total viable count, Enterobacteriaceae, staphylococci and lactic acid bacteria), physicochemical (pH and water activity) and chemical (moisture, fat and protein) properties of the sausages was assessed during the fermentation process.A sensory evaluation of the end product was also performed.The results showed the impressive efficacy of EOs against all tested strains, with minimum inhibitory concentrations of 1.25% (v/v) for Escherichia coli and Staphylococcus aureus and 5% for Listeria monocytogenes.The hygienic quality of the Merguez sausages treated with EOs improved, as evidenced by the reduction in counts of Enterobacteriaceae, total viable bacteria and staphylococci at the end of the ripening period.Conclusion, significance and impact of study: Both microbiological assessments and sensory analyses indicated that sausages treated with 1% thyme EO exhibited the most promising results.Therefore, incorporating a 1% concentration of thyme EO in the fermentation processes emerges as a potential strategy for improving the hygienic and organoleptic characteristics of Merguez sausages.