Effects of lactic acid bacteria (LAB) on the survival and growth of some food-borne pathogens in fermenting wakalim, a traditional Ethiopian fermented beef sausage

Abstract

Wakalim is spiced naturally fermented traditional beef sausage in Ethiopia. During its fermentation using pure starter cultures of Lactobacillus plantarum1 or Pediococcus pentosaceus1 and mixture of the two starters, the counts of Salmonella typhimurium DT104 and Escherichia coli dropped sharply after 12 h of fermentation and complete elimination was noted on the third or fourth day. The count of Staphylococcus aureus dropped gradually but remained at < log 4 cfu/g at the end of fermentation. The pathogens were eliminated faster with the mixed cultures than with the respective pure cultures. The pH of fermenting wakalim dropped from about 6.0 to 4.5 ± 0.2 during the first 48 h of fermentation. Thereafter, the pH rose gradually in all cases possibly due to depletion of fermentable sugars and growth of proteolytic microorganisms. LAB obtained from the spontaneous fermentation of wakalim may have potential for large scale application as starter cultures.