Heterofermentative process in dry fermented sausages - A case report

Abstract

In certain circumstances the fermentation process in dry fermented sausages converts to heterofermentation pathway leading to acetic acid and carbon dioxide beside lactic acid. The study describes two cases of undesirable heterofermentation in dry sausages from two different producers. In the sausage samples (n = 7) the pH value and the content of lactic and acetic acids were measured. Microbial analysis focused on quantitative and qualitative detection of lactic acid bacteria. The acetic acid content varied from 24.28 to 67.41 μmol·g-1 dry matter, in the case of samples from the second producer the content of acetic acid (48.45 to 67.41 μmol·g-1 dry matter) was higher than the lactic acid content (20.98 to 29.02 μmol·g-1 dry matter). The lactobacilli strains from the sausages were assigned to the corresponding species by Matrix-Assisted Laser Desorption-Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) and classified to three groups according to the sugar fermentation pattern (obligately homofermentative, facultatively heterofermentative and obligately heterofermentative) and they caused the heterofermentation process in the samples of dry fermented sausages. The description of the case of heterofermentation process in dry sausages is unique and there is little information about this topic.