Microbial and sensory changes in vacuum-packed frankfurter-type sausage by Lactobacillus alimentarius and fate of inoculated Salmonella enteritidis

The ability of a commercial culture identified as Lactobacillus alimentarius inoculated as protective culture at two different levels, i.e. 1.6x10(3) cfu cm(-2) and 1.6x10(5) cfu cm(-2) of slice, to extend the shelf-life of sliced vacuum-packed frankfurter-type sausage, known as pariza, during refrigeration (6-8 degrees C) was investigated in comparison to control samples. The addition of protective culture increased lactic acid bacteria and suppressed other saprophytic micro-organisms like pseudomonads and Brochothrix thermosphacta. Sliced pariza, vacuum-packed in pouches with oxygen transmission rate of 3.55x10(-3) cm(3) m(-2) 24 h(-1) Pa-1 and inoculated with protective culture was acceptable up to 51 and 42 days when the level of inoculation was 1.6x10(3) cfu cm(-2) and 1.6x10(5) cfu cm(-2) of slice, respectively, compared to control pariza with a shelf-life of 23 days. The influence of L. alimentarius on inoculated Salmonella enteritidis on freshly produced pariza held under refrigeration (6-8 degrees C) in vacuum-packaging in pouches with oxygen Transmission rate 3.55x10(-3) cm(3) m(-2) 24 h(-1) Pa-1 was also evaluated following their counts during storage. Although slightly lower growth rates of Salmonella were observed in samples inoculated with protective culture L, alimentarius, multiplication of S. enteritidis could not be prevented. The biopreservation system tested here could not guarantee the safety of vacuum-packed sliced pariza when severe contamination with Salmonella occurs in this product. (C) 1998 Academic Press Limited.