Incidence de facteurs alimentaires sur l'obtention de résultats faux positifs lors de la détection des antibiotiques dans le lait par la méthode Delvotest SP®

Abstract

-Incidence of complemented feed on false positive results with Delvotest SP® for detection of antibiotics in milk. The study described in this paper was performed to show the influence of feed complemented by minerais, oligo-elements and vitamins (CM V) on the results of Delvotest SP®. Three trials were developed. In the first trial, a group of 13 dairy cows was divided into two subgroups of six and seven cows, receiving the first one a feed basis without CMV, the second one, the same feed basis added of 100 g CMV per day. During the second trial, the dose of CMV was doubled for the last seven cows. During the third trial, ail the 8 cows were grazing. The four cows of the test group received 200 g of CMV per day. The two homogeneous groups of cows (somatic cells, number of lactations) were followed for detection of inhibitors in milk using Delvotest SP®. The test gave positive results with milk from complemented cows during the first and the second trials. Ali results were negative during the third trial. Feed appears to be a factor that may give false positive results in the determination of antibiotics in milk with Delvotest SP®. © Inra/Elsevier, Paris.

Cyclic Lipodepsipeptides Produced by Pseudomonas spp. Naturally Present in Raw Milk Induce Inhibitory Effects on Microbiological Inhibitor Assays for Antibiotic Residue Screening

“…The ability of some vitamin binding proteins to inhibit the growth of bacterial species was suggested by Mullan [20] . Feed complemented with minerals, oligo-elements and vitamins also appear to be a factor that may give rise to false-positive results in the determination of antibiotics in milk with Delvotest SP [21] .…”

Evaluation of false positive results in microbial inhibitor tests for screening antibiotics in goat milk

“…Several factors could contribute to false positive results on microbial inhibitors tests, since these tests are non-specific and may be affected by any substance or compound capable of inhibiting the growth of the test-organism. Natural inhibitors like lactoferrin and lysozyme (Carlsson and Björck, 1987;Pan et al, 2007), an elevated somatic cell count (Carlsson and Björck, 1989;, also feed complemented with minerals, oligo-elements and vitamins (Romnée et al, 1999), high concentrations of fatty acids Carsson and Björck, 1992) and the lipodepsipeptides produced by certain Pseudomonas species among others factors have been related with false positive outcome results.…”