A study of the role of different nitrite concentrations on human pathogenic bacteria in fresh spreadable ham and onion sausage

Fresh spreadable ham and onion sausage is an uncooked and briefly fermented product. We investigated whether higher nitrite concentrations improve its microbiological stability. Concentrations higher than 0.5% nitrite in the curing salt (NCS) have been permitted since 1998. Fresh spreadable ham and onion sausage was produced with nitrite concentrations of 0.5% and 0.9% in the NCS and was inoculated with bacteria, normally associated with food contamination, in order to assess bacterial growth. Sausages were examined microbiologically at two-day intervals over a period of 15 days (shelf-life). Growth of Listeria monocytogenes was inhibited by NCS, but only a little difference was observed between the two concentrations. Whereas growth of Enterobacteriaceae was also inhibited, inhibitory effects of NCS on Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and lactic acid bacteria were not shown. The maximum residual nitrite content of the sausages was 53 mg NaNO2 (per kg wet weight)--the permitted maximum level is 100 mg NaNO2 per kg sausage.