Feasibility of Using Sucrose Laurate to Control Thermophilic Spoilage in Low-Acid Canned Rations

The individual and combined effects of sucrose laurate (SL, L-1695), tert-butylated hydroxyanisole (B) ethylenediamine tetraacetate (E) and nisin were evaluated in a liquid growth medium (antibiotic assay medium + 1% soluble starch, AAMS) to determine their antagonistic action against the thermophilic flat-sour bacterium, B. stearothermophilus. Results indicated that on AAMS agar (pH 6.5 - 6.8) the minimum inhibitory concentration (MIC) of these additives required to prevent germination and outgrowth of B. stearothermophilus spores were > 50-60 ppm for SL and SLEB, while the MICs for BHA, EDTA and nisin were > 150, 350 and 400 ppm, respectively. During incubation (144 h at 55 deg C) in AAMS broth (pH 6.8) containing 50 ppm of SL and SLEB, respectively, the vegetative cell number increased ca. 2 log10 cycles, e.g., 10(3) -.10(5) CFU/mL. At similar concentrations of BHA, EDTA and nisin, no inhibition was observed. SL and SLEB did, however, prolong the lag phase and arrest log phase growth; BHA, EDTA and nisin did not exhibit similar inhibition tendencies. Differences in the inhibitory properties of SL and SLEB, relative to B. stearothermophilus, were not statistically significant (p>0.05). Under the conditions defined in this study, it would appear that SL and SLEB may have some utility in protecting thermally processed military rations from thermophilic spoilage.