Evaluation of deodorized yellow mustard concentrations for control of Escherichia coli O157:H7 viability in dry fermented sausage

Although 6% (w/w) deodorized mustard powder can achieve the mandatory 5 Log CFU/g reduction of Escherichia coli O157:H7 in 18 d during dry-fermented sausage manufacture, sensory analysis showed that mustard concentrations lower than 6% were more acceptable to consumers. In the present work the antimicrobial effectiveness of lower levels of deodorized (autoclave-treated) mustard was evaluated against E. coli O157:H7. Concentrations of 2% and 4% (w/w) mustard treated at 115 °C for 15 min were first tested in Mueller-Hinton broth (14 d) and then during fermented sausage manufacture (42 d) against E. coli O157:H7. During tests in broth, 4% deodorized mustard yielded a significantly greater reduction in E. coli O157:H7 numbers than 2% at 14 d. Mixtures of autoclave-treated and hot mustard at 1% or 2% (w/w) each were equally or slightly less antimicrobial against E. coli O157:H7 in sausage than their corresponding concentrations (2% or 4%) of deodorized mustard. While 4% deodorized mustard in sausage reduced E. coli O157:H7 viability by 5 Log at 28 d, 2% deodorized mustard did not achieve the reduction target. Mustard addition influenced starter culture recovery by causing a reduction in Staphylococcus carnosus numbers, but did not change Pediococcus pentosaceus viability during tests. It is probable that a minimum threshold between 3 and 4% (w/w) deodorized mustard may be required to assure control of E. coli O157:H7 viability in dry-fermented sausages.