Evaluation of the combined effect of chitosan and lactic acid bacteria in alheira (fermented meat sausage) paste

This study aimed to assess the efficacy of chitosan, Pediococcus acidilactici HA-6111-2 (bacteriocinogenic strain with antilisterial activity) and Pediococcus pentosaceus HA-3083-3 (a nonbacteriocinogenic strain), added individually or in combination, in the control of Listeria innocua, Staphylococcus aureus, Escherichia coli and Salmonella typhimurium during storage of Alheira paste at 4C. The behavior of pathogenic bacteria in the food matrix was significantly affected by the addition of chitosan. Chitosan at 0.3% reduced pathogenic bacteria counts in Alheira paste by 2-3 log cfu/g during the first 7 days of storage. This effect was increased when chitosan was used synergistically with lactic acid bacteria (LAB) (P < 0.05). Sensory evaluation showed that addition of chitosan to Alheira did not affect sensory attributes. To our knowledge, this is the first study demonstrating the combined effect of bacteriocinogenic or nonbacteriocinogenic LAB and chitosan against pathogenic bacteria in fermented meats.