Screening of antibiotic residues in ewe milk destined to cheese by a commercial microbiological inhibition assay

Miho Yamaki (1, 2) , M. Isabel Berruga (1, 2) , Rafael Lisandro Althaus (3) , Pilar Molina (4) , Ana Molina (1, 2)

1 Ciencia y Tecnología Agroforestal
2 Seccion Calidad Alimentaria. Instituto de Desarrollo Regional
3 FCV - Facultad de ciencias veterinarias [Sante Fe]
4 Ciencia Animal

Bulk ewe milk from Spanish dairy farms situated in the Castilla-La Mancha region, and destined to Protected Denomination of Origin (PDO) Manchego cheese, were analysed each month for antimicrobial residues during one year. For this study a microbiological assay specific for ewe milk (Eclipse “100ov”®) was used. The number of positive samples by the Eclipse “100ov”® test was 2.6%. A second examination of positives following heat treatment at 82ºC for 10 min showed a reduction of up to 0.9%, in other words) 63% of the samples detected corresponded to “false positives”. Twenty-five percent of the confirmed positives were identified as β-lactams by a penicillinase solution, the rest corresponded to antimicrobial compounds that could not be identified. The month of collection was related to the probability of positive results, but not other factors such as somatic cell counts (SCC), bacteriology or composition (fat and protein). The highest rates of positives were observed in September and October. Finally the results were compared with the obtained by the Delvotest SP® method and revealed the detection of an inferior number of positive samples on the part of the Eclipse “100ov”® method.

Mots clés: Life Sciences

Miho Yamaki, M. Isabel Berruga, Rafael Lisandro Althaus, Pilar Molina, Ana Molina. Screening of antibiotic residues in ewe milk destined to cheese by a commercial microbiological inhibition assay. Food Additives and Contaminants, 2006, 23 (07), pp.660-667. ⟨10.1080/02652030500428655⟩. ⟨hal-00578285⟩