Combinatorial Bacteriostatic Activities of Garlic Bulb-, Lemon Peel- and Orange Peel Extracts Against Common Foodborne Bacteria in a Tomato-Based Pasta Meat Sauce

Abstract

This study was conducted to characterize the bacteriostatic activities of aqueous garlic bulb- (GBE), ethanolic lemon peel- (ELPE), and ethanolic orange peel (EOPE) extracts against Escherichia coli K-12, E. coli O157:H7, Salmonella enterica serovars, Listeria monocytogenes, and Staphylococcus aureus in a tomato-based meat sauce. The maximum permissible supplementation (MPS) levels of GBE, ELPE, and EOPE in the meat sauce formulation determined through sensory evaluations were 6.0%, 3.0%, and 3.0%, respectively. However, the MPS values of ELPE and EOPE did not inhibit any of the test organisms in the subsequent antibacterial assays, with minimum inhibitory concentration (MIC) values of 6.0 – 9.0% (ELPE) and 7.5 – 10.0% (EOPE). On the other hand, GBE had an MIC values range of 1.0 – 2.5%. Thus, the study also determined the minimum inhibitory combination (MICo) values of GBE+ELPE and GBE+EOPE. Results showed that co-supplementations of the test extracts resulted in MICo values of 3.0% GBE +3.0% ELPE and 3.0% GBE +3.0% EOPE. Supplementation of the meat sauce with these MICo resulted in products with similar consumer acceptability scores as the non-supplemented control. Supplementation of inoculated meat sauce with the MICo of the test extracts exhibited bacteriostatic effect on selected pathogens in time-temperature abused (31°C, 8 h.) meat sauce.