Microbial ecology of a small-scale facility producing traditional dry sausage

The microbial ecology of a small-scale facility producing traditional dry sausage (without addition of starter cultures) was investigated at 17 control points (12 processing surfaces and equipments samples, 5 raw materials and products samples) and at different periods: winter and spring. Technological flora (lactic acid bacteria, staphylococci/Kocuria and yeast/moulds) populations were low in processing surfaces and equipments (below 10(2) c.f.u/cm(2)), but reached a level of about 10(6)-10(7) c.f.u/g for lactic acid bacteria and staphylococci/Kocuria and about 10(4) c.f.u/g for yeasts/moulds in the final product. Counts of enterococci were low in most of processing surfaces and equipments and increased in the batter and the sausage-1 week; but declined after 8 weeks of ripening. Differences in temperatures of the processing facility recorded in winter and in spring influenced the hygienic quality of raw materials. Pseudomonas and Coliforms populations enumerated from raw materials in spring were about 3 log(10) c.f.u/g superior compared to enumeration results recorded in winter. While Pseudomonas population declined remarkably in the final product, Coliforms population remained higher. Staphylococcus aureus was undetected in spring; however in winter, its population was about 2.5 log(10) c.f.u/g in the final product after 9 weeks ripening. One isolate originating from the stuffing machine was identified as Listeria monocytogenes. Finally, 9 presumptive Salmonella were identified as belonging to Hafnia alvei, Providencia alcalifaciens, Proteus vulgaris, P. penneri and Morganella morganii species. These results emphasize the necessity of improving the general hygienic conditions and also technological process of sausage production in this processing facility. (C) 2005 Elsevier Ltd. All rights reserved.