Hashemite University, Jordan
Title: Use of plant essential oils to inhibit Salmonella enterica in hummus
Biography: Mahmoud Abu Ghoush
This study aims to screen the antimicrobial activity of different essential oils against Salmonella and investigate the inhibitory effect of cinnamon or thyme oils against Salmonella and Mesophilic Aerobic Bacteria (MAB) in hummus. Different essential oils (thyme, sage, cardamom, laurel, rosemary, cinnamon, ginger, fir) were tested against five Salmonella serotypes. Salmonella-inoculated hummus was treated with 0.5 to 1.5% thyme or cinnamon oils (which exhibited the highest antimicrobial activity using disc-diffusion method with inhibition zones of 22.5-38.5 mm in diameter) and stored at 4 or 10 °C. Salmonella cells were not detected in hummus treated with 0.5-1.0% cinnamon oil by 7 and 1 d, respectively, at 4 or 10 °C. Cinnamon oil at 0.5-1.5% reduced the MAB in hummus by 1.3-4.6 log CFU/g at 4 °C. However, addition of 0.5-1.5% thyme oil into hummus reduced Salmonella by 1.0-2.9 log CFU/g, respectively, at 4 °C by 10 d. Thyme oil also inhibited growth of MAB in hummus and the count remained constant until the end of storage period at 4 °C. While at 10 °C, thyme oil showed lower inhibitory effect. Cinnamon and thyme oils were effective in inhibiting Salmonella in hummus. Using cinnamon and thyme oil may improve the safety and extend the shelf-life of hummus.