Effect of nitrite on a bacteriocinogenic Lactococcus lactis transconjugant in fermented sausage

Sodium nitrite is added to salami to impart a typical cure colour and flavour in addition to its functions as an antioxidant and antimicrobial agent. Three levels of nitrite, high, medium and low (100, 50 and 20 mg sodium nitrite kg^-1 respectively) were used to investigate the effect of nitrite on a Lactococcus lactis starter culture. Salami was fermented with Lc. lactis DPC 4268, a bacteriocinogenic transconjugant Lc. lactis DPC 4275 (producing lacticin 3147), and Lactobacillus sake LAD (high nitrite only) as a control. Nitrite concentration had no perceptible effect on the sausage texture, or on CIE L* and b* colour values. There was no significant difference (p>0.05) in the redness (a* values) between high nitrite bac+ salami and either control. Sensory evaluation of the product showed that there was no perceptible difference in colour between salamis containing high or medium nitrite treatments. Nitrite had a negative effect on the growth of both Lc. lactis starters, as well as on lacticin 3147 production; however, the flavour of high nitrite salami was unaffected and the product was highly acceptable to >80% taste panellists.