Effect of white mustard essential oil on inoculated Salmonella sp. in a sauce with particulates.

White mustard essential oil (WMEO), from white mustard seed (Sinapis alba L.), is obtained by solvent extraction of defatted and wetted ground mustard; endogenous myrosinase catalyzes the hydrolysis of the glucosinolate sinalbin to yield 4-hydroxybenzyl isothiocyanate (4-HBITC), the antimicrobial component of WMEO. Sauce with particulates was made by mixing sauce, which served as the carrier for WMEO, with frozen vegetable and chicken particulates inoculated with Salmonella sp. WMEO (at 250 to 750 ppm of 4-HBITC) was able to reduce inoculated Salmonella counts by 0.8 to 2.7 log (CFU/g) in a frozen sauce with particulates in a dose-dependent manner, starting from the point of formulating the sauce through the microwave cooking step. High-pressure liquid chromatography-based analytical data confirmed that 4-HBITC was present in all of the samples in the expected concentrations and was completely hydrolyzed after the recommended cooking time in microwave ovens. In another experiment simulating unintentional abuse conditions, where the WMEO containing sauce with particulates was kept at room temperature for 5 h, WMEO (at 250 to 750 ppm of 4-HBITC) was able to reduce inoculated Salmonella counts from the point of first contact and up to 5 h by 0.7 to 2.4 log (CFU/g). Despite the known hydrolytic instability of the active component 4-HBITC, particularly at close to neutral pH values, WMEO was effective in controlling deliberately inoculated Salmonella sp. in a frozen sauce with particulates.