Tehran University of Medical Sciences Journal of Food Safety and Hygiene 2476-3241 10 1 2024 09 10 59 72 Souhir Kmiha IPT Chedia Aouadhi ISBB/IPT Khouloud Aziza IPT Abderrazak Maaroufi University of Tunis El Manar (UTM), Tunis, Tunisia. 2024 04 13 2024 08 26 Antibacterial capacities of monolaurin and nisin on the growth of vegetative cells of three spore-forming bacteria isolated from cow milk collected from Tunisia (Terribacillus aidingensis, Bacillus sporothermodurans and Paenibacillus sp and) were evaluated. Nisin or monolaurin, at different concentrations, can inhibit the growth of three Bacillus. 500 IU/mL and 25 μg/mL corresponded to the minimum inhibitory concentrations of nisin and monolaurin, respectively. The growth of the tested species in the presence of sub-lethal concentrations of monolaurin and nisin was monitored in UHT milk for 7 days at three different temperatures (4°C, 37°C and 25°C). Nisin (250 IU/mL) was able to induce an immediate reduction (after 3 h of incubation at 4°C) of Bacillus species growth (5 log for B. sporothermodurans, 4 log for Paenibacillus sp and 3.2 log for T. aidingensis). Also, monolaurin (25 µg/mL) reduce the growth, at 4°C of B. sporothermodurans by 5 log, Paenibacillus sp by 3 log and T. aidingensis by 4 log, after 3 h of incubation. In the presence of nisin or monolaurin, it can be observed a low reduction in cell growth followed by rapid regrowth which can attenuate 10 log, at 37°C and 25°C. The obtained data elucidate the potency of nisin and monolaurin, and the application of these antimicrobial agents at low temperatures (4°C) to decontaminate any product from these spoilage bacteria. https://jfsh.tums.ac.ir/index.php/jfsh/article/view/488 https://jfsh.tums.ac.ir/index.php/jfsh/article/download/488/239