Effect of pre-ripening on microbial and chemical changes in dry fermented sausages

The effect of pre-ripening at 5 degrees C on microbial changes, nitrate reduction and proteolysis in both naturally fermented and inoculated (Lactobacillus sake and Staphylococcus carnosus) sausages was investigated. Micrococcaceae levels were significantly higher (P<0.05) in pre-ripened batches, whether or not starter cultures were inoculated; this was in accordance with both the lower (P<0.05) lactic acid bacteria levels and higher (P<0.05) pH values reached at the end of the process. In non-inoculated batches contents of residual nitrate were lower (P<0.05) as a consequence of the stronger (P<0.05) pH drop caused by L. sake inoculation which can inhibit nitrate reductase activity. However, this inhibitory effect can be significantly (P<0.05) reduced by applying a pre-ripening treatment. Maximal non-protein nitrogen (NPN) and amine nitrogen (AN) increases were detected in inoculated batches submitted to pre-ripening, although a general significant (P<0.05) effect of pre-ripening on proteolysis was not inferred. Pre-ripening can therefore be considered as a way of preventing an early Micrococcaceae inhibition and achieving a more effective nitrate reduction when inoculating a mixed starter culture including a lactic acid bacteria strain. (C) 1997 Academic Press Limited.