Sulfite-Inhibition of Enterobacteriaceae Including Salmonella in British Fresh Sausage and in Culture Systems

Abstract

Of the sulfite (600 μg/g) added to British fresh (breakfast) sausage, ca. 26% was lost irretrievably and a further 24% bound reversibly during manufacture. Residual free sulfite prevented growth of Enterobacteriaceae at 4, 10 and 15°C but not at 22°C storage, whereas these organisms grew and caused souring of unsulfited sausage at all storage temperatures. The number of viable cells of Salmonella virchow did not change during storage of unsulfited or sulfited sausage meat at and below 9°C, whereas extensive growth occurred in unpreserved sausage meat at 15, 20 and 25°C. Growth in sulfited sausage meat occurred only with storage at 25°C, a temperature at which the most extensive sulfite loss and binding occurred. Enterobacter cloacae and Escherichia coli became the numerically dominant Enterobacteriaceae in sulfited sausage, whereas Enterobacter agglomerans and Hafnia alvei did so in the absence of sulfite. The sensitivity of members of the Enterobacteriaceae to sulfite in broth culture correlated well with the relative abundance of these organisms in the sulfited or unsulfited product. Sulfite-induced stasis of Enterobacteriaceae other than Enterobacter agglomerans maintained for upwards of 20 h at 30°C was released when the residual free sulfite was bound with acetaldehyde or neutralized with hydrogen peroxide. In contrast, the 8 serotypes of Salmonella tested could not be released from growth stasis with these agents, and death ensued after 25 hat 30°C.