Characterization of the bacterial spoilage flora in marinated pork products

Aims: To investigate the microbiota in marinated, vacuum-packed pork and to characterize isolated bacteria with regard to their spoilage potential. Methods and Results: Laboratory marinated pork meat and commercial products from three Norwegian producers were examined. Lactic acid bacteria dominated in all products at the expiration date. The flora in marinated products was similar only for products from the same plant. Strains of Lactobacillus algidus, Lactobacillus sakei, Lactobacillus curvatus, Carnobacterium divergens, Carnobacterium maltaromaticum, Leuconostoc mesenteroides, Leuconostoc carnosum and Leuconostoc sp. were isolated and tested for their spoilage potential. Samples inoculated with Lact. algidus or Leuc. mesenteroides were rated as most unpleasant by randomly selected people. A sensory panel scored samples with Lact. algidus highest for sour and intense odour. Lactobacillus algidus was found in products from two out of three production plants. Culture-independent DNA isolation confirmed that cultivation on Blood agar at 20°C yielded a representative picture of the total flora in marinated flintsteak. Conclusions: Lactobacillus algidus may be an important, but underestimated, spoilage organism that needs to be focused on more when spoilage of vacuum-packed meat is considered. Significance and Impact of the Study: Routine microbial testing may have to be revised in order to detect spoilage LAB that are unable to grow under currently used conditions.