title: A qualified presumption of safety approach for the safety assessment of Grana Padano whey starters.
abstract: A Qualified Presumption of Safety (QPS) approach was applied to dominant lactic acid bacteria (LAB) associated with Grana Padano cheese whey starters. Thirty-two strains belonging to Lactobacillus helveticus, Lactobacillus delbrueckii subsp. lactis, Streptococcus thermophilus, and Lactobacillus fermentum, and representing the overall genotypic LAB diversity associated with 24 previously collected whey starters [Rossetti, L., Fornasari, M.E., Gatti, M., Lazzi, C., Neviani, E., Giraffa, G., 2008. Grana Padano cheese whey starters: microbial composition and strain distribution. International Journal of Food Microbiology 127, 168-171], were analyzed. All L. helveticus, L. delbrueckii subsp. lactis, and S. thermophilus isolates were susceptible to four (i.e. vancomycin, gentamicin, tetracycline, and erythromycin) of the clinically most relevant antibiotics. One L. fermentum strain displayed phenotypic resistance to tetracycline (Tet(R)), with MIC of 32 microg/ml, and gentamycin (Gm(R)), with MIC of 32 microg/ml. PCR was applied to this strain to test the presence of genes tet(L), tet(M), tet(S), and aac(6')-aph(2')-Ia, which are involved in horizontal transfer of Tet(R) and Gm(R), respectively but no detectable amplification products were observed. According to QPS criteria, we conclude that Grana cheese whey starters do not present particular safety concerns.
authors.affiliation: Agriculture Research Council, Research Centre for Forage and Dairy Productions (CRA-FLC), Viale Piacenza 29, 26900 Lodi, Italy.
authors.forename: Lia
authors.initials: L
authors.lastname: Rossetti
authors.forename: Domenico
authors.initials: D
authors.lastname: Carminati
authors.forename: Miriam
authors.initials: M
authors.lastname: Zago
authors.forename: Giorgio
authors.initials: G
authors.lastname: Giraffa
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002611:Cheese / Q000382:microbiology*; D024881:Drug Resistance, Bacterial; D005516:Food Microbiology; D007558:Italy; D007778:Lactobacillus / Q000187:drug effects / Q000502:physiology*; D008894:Milk Proteins; D048249:Streptococcus thermophilus / Q000187:drug effects / Q000502:physiology*; D000067816:Whey Proteins
chemical_list: D000900:Anti-Bacterial Agents; D008894:Milk Proteins; D000067816:Whey Proteins