Garlic and Onion as Natural Antimicrobial Agent Against Salmonella in Homemade Mayonnaise

Abstract

Garlic and Onion as Natural Antimicrobial Agents Against Salmonella in Homemade Mayonnaise LIYUAN HAO Dept. of Food & Nutrition Graduate School of Hanyang University Salmonellosis, as one of the primary threats to global public health, ranks as the second most common human foodborne gastrointestinal infection after campylobacteriosis. Given that eggs are one of the main vectors for the transmission of salmonellosis, the microbiological safety monitoring and control of cross-contamination become especially important. The research focuses on assessing the surveillance and management of microbial presence in eggs subjected to diverse processing techniques in South Korea. Additionally, it delves into the efficacy of natural antimicrobials such as garlic and onion when used in the preparation of homemade mayonnaise. Salmonella contamination of eggs and egg shells has been identified as a public health concern worldwide. In this study, no Salmonella was detected in egg samples from Korean farms, indicating the effectiveness of the local regulatory system and high standards in microbial control. The study analyzed the antibacterial and antioxidant properties of homemade mayonnaise using various processing methods (juice and paste) and garlic and onion concentrations. The results showed that mayonnaise with 2% garlic juice was most effective against S. typhimurium 2421, significantly reducing bacterial numbers by a factor of 1000, while the addition of onion had a relatively weaker effect. Further experiments showed that mayonnaise containing both garlic and onion (such as G1O3P Mix, G1O3J Mix and G2O4J Mix) significantly outperformed the single- additive approach in antibacterial performance. G2O4J Mix, in particular, was able to reduce the population of S. typhimurium 2421 by less than 10 CFU/ml in 24 hours. Protein leakage experiments and SDS-PAGE results supported the conclusion that mayonnaise inoculated with high concentrations (> 109 CFU/ml) of S. typhimurium 2421 exhibited stronger bacterial adaptation capabilities . The experiments showed that ground garlic and onion paste have superior antioxidant (eg: Garlic paste :307.68±2.64 mg GAE/g FW ) properties than their juice form (eg:Garlic juice :283.77±6.52 mg GAE/g FW ), with residue left after juice extraction showing the strongest antioxidant properties (eg:Residue after juice extraction of garlic :323.14±2.25 mg GAE/g FW ). Mayonnaise also contains certain antioxidants (29.51±1.50 mg GAE/g The G2O4J Mix demonstrated superior moisture stability, with low-temperature conditions being particularly beneficial for maintaining these stable physicochemical properties. Homemade mayonnaise without added antimicrobial agents maintains a bacterial reduction level of 102 CFU/mL over 50 hours, suggesting consumption within this time frame. When the G2O4J mixture (2% garlic juice + 4% onion juice) is added, the mayonnaise significantly reduces the count of S. typhimurium 2421 by about 105 times within 24 hours under room temperature conditions. After 72 hours, there is a pH increase of 2.0 compared to the control group's increase of 3.4 from the starting point. Therefore, it is recommended to consume mayonnaise with the G2O4J mixture within 72 hours. Based on this study, it is recommended to use a recipe containing 2% garlic juice and 4% onion juice for making mayonnaise, to enhance food safety and quality. Experiments have shown that this approach significantly reduces the concentration of Salmonella typhimurium 2421 from 106 CFU/mL to below 100 CFU/mL within 24 hours. At 25°C, the antioxidant capacity of the mayonnaise reached 64.14±1.14 mg GAE/g FW, demonstrating good antioxidant properties. Moreover, after a 96-hour test period, the mayonnaise exhibited superior moisture stability (85.31%/88.2%). In terms of sensory evaluation, this recipe scored 4.22/5, indicating widespread acceptance among the general public. Conclusively, this research demonstrates the potential of natural antimicrobials in raw egg-based food production, hence improving safety and quality. It offers the food sector a new perspective by providing scientific data and practical recommendations in food safety and microbial management.