Application of whole genome sequenced selected Pediococcus acidilactici to tailor the making of the spreadable fresh ewe’s milk “Quadrello di Ovino” cheese to the production area

Abstract

The aim of this study was to utilize Pediococcus acidilactici strains as starter microorganisms in producing the fresh ewe’s cheese “Quadrello di Ovino”. Whole-genome analysis confirmed the absence of virulence factors (such as hemolysins) and genes conferring resistance to commonly used antibiotics indicated by the European Food Safety Authority. A control trial was conducted with commercial freeze-dried starters (CP), against the novel experimental cheese (EXP) inoculated with pediococci. Cheeses from both the control and experimental production showed high levels of lactic acid bacteria (LAB). Mesophilic LAB were present at 7.09 and 8.50 log CFU/g, respectively, while thermophilic LAB were found at 6.95 and 8.46 log CFU/g, respectively. Both cheeses showed no presence of spoilage or pathogenic microorganisms according to plate counts. While there were no significant differences in fat and protein content between them, the EXP cheese had a slightly higher protein content (16.85 %). Additionally, both cheeses had a complex profile of volatile organic compounds, with higher monounsaturated fatty acids (oleic acid) and polyunsaturated fatty acids (linoleic and linolenic acids) content in the EXP cheese at 26.80 %, 2.61 %, and 0.70 %, respectively. From a sensory perspective, the EXP cheese showed a diminished persistence of the taste typical of ewe’s milk and a reduction in the unpleasant animal odour commonly found in cheeses made from small ruminants, while enhancing paste homogeneity and odor intensity. These observations indicate the product’s promising potential, considering the increasing demand in local and foreign markets for spreadable cheeses with creamy consistence.