Comparison of Antilisterial Effects of Two Strains of Lactic Acid Bacteria during Processing and Storage of a Portuguese Salami-like Product “Alheira”

Abstract

Traditional smoked and/or cured salami-like products are much appreciated by Southwest European consumers. However modern consumers require products that not only have high appealing sensory attributes but are also safe. In this work the effect of the application of two bacteriocinogenic lactic acid bacteria (LAB) Lb. plantarum ST202 and Lb. sakei ST153 for controlling Listeria monocytogenes growth in “Alheira”, a traditional salami-like product, was investigated. The paste of ‘‘Alheira’,’ produced by an industrial meat company, was sterilized by autoclaving before inoculation and L. monocytogenes growth was evaluated during 15 days of storage. Both LAB strains showed antilisterial activity in the inoculated paste, but as in preliminary experiments with sterilized minced pork meat only strain ST153 presented activity against L. monocytogenes. it was decided, for further industrial tests, to use only this strain. Therefore, the effect of Lb. sakei ST153 against monocytogenes in industrially processed “Alheira”, packed under vacuum or under modified atmosphere (MA) (20 % CO2 and 80 % N2), was evaluated during 7 days storage at 4 °C. The effect of the inoculation of the bacteriocinogenic culture in the organoleptic properties of “Alheira” was also investigated. A quantitative descriptive sensory test was performed by a semi-trained panel after 5 days storage. No significant differences were observed in the microbiological and sensory quality of “Alheira” packed under vacuum or MA. A significant reduction in the level of L. monocytogenes was observed in the presence of Lb. sakei ST153 (2 log cycles reduction during the first 7 days). Results showed that panellists did not find significant differences between “Alheira” with Lb. sakei ST153 addition and commercial control, except for mass connection, acid taste and a typical taste. Despite that, both samples were scored above conformity limit. Thus, the application of LAB is a very promising mean of preventing L. monocytogenes growth in “Alheira”.