Accelerated solvent extraction of animal feedingstuffs for microbial growth inhibition screening for the presence of antimicrobial feed additives

Abstract

Three plate systems (combinations of indicator organism and growth medium) were evaluated for the detection of analytical standards of the banned feed additives avoparcin, bacitracin zinc, spiramycin, tylosin and virginiamycin. When authorized in the EU, the previously recommended minimum inclusion rate (MIR) for each compound was 5 mg kg(-1). One of the plate systems (Micrococcus luteus ATCC 10240, nutrient agar) detected all five additives. This plate was used in a further study that evaluated the suitability of accelerated solvent extraction (ASE) as a first step in the development of a rapid single-plate screening assay. A drug-free (negative control) feedingstuff was fortified with the compounds (0-50 mg kg(-1)), extracted by ASE and the extracts applied to the plate at each of three pH ranges - unadjusted extract (pH 5.7-5.9), pH 6.5 and 8.0. At pH 6.5, sub-MIR concentrations of virginiamycin and tylosin were detectable. Avoparcin was detectable at 6.3 mg kg(-1). The detection of zinc bacitracin was#10; pH-independent (10 mg kg(-1)). At pH 8.0, spiramycin was detectable at 5.4 mg kg(-1). Mean +/- SD analytical recoveries from fortified feedingstuffs (n = 10) ranged from 57 +/- 1.5% for avoparcin to 96 +/- 4% for virginiamycin. The five additives were also detectable following ASE extraction from a range of different feedingstuffs fortified with each of the drugs. A further 24 compounds permitted for use in animal feeds were tested. Of these, nine were detectable at their recommended MIR. It is concluded that ASE is a versatile technique suitable for the automated extraction of a range of antimicrobials from animal feedingstuffs. Employing ASE with this single-plate detection system permits the rapid antimicrobial screening of animal feedingstuffs and allows the detection of the banned additives. Whilst the method is applicable as a screening test, more specific postscreening methods would be necessary for subsequent identification (and quantification) of antimicrobials in screening-positive samples.

Antibiotic residues in broiler and layer meat in Chittagong district of Bangladesh

“…Microbiological inhibition tests are considered as multi-residue screening tests for antibiotics in milk, meat and other animal tissues. Microbial tests are commonly used for the screening of antibiotic residues in animal tissues in a residue monitoring programmed, and their role was extended to the identification of antibiotics in animal feeding stuffs [13]. From the above facts, it may be mentioned these antibiotic residues might be potential hazards for human as well as animal health and a great obstacle to export poultry meat.…”

Ανάπτυξη Και Επικύρωση Μεθόδου LC-MS Για Τον Προσδιορισμό Υπολειμμάτων Αντιβιοτικών Και Μεταβολιτών Τους Σε Ψάρια

“…141 Πλήθος εφαρµογών έχουν δηµοσιευθεί για την εκχύλιση ουσιών από διάφορα δείγµατα. 165,[174][175][176][177][178][179][180][181][182][183][184][185][186][187][188][189][190][191][192] 3.5. «Επίδραση του µητρικού υλικού» στην υγροχρωµατογραφία-φασµατοµετρία µαζών 3.5.1 Γενικά Η αρχική αντίληψη ότι η τεχνική LC/MS εγγυάται εκλεκτικότητα και αξιοπιστία, έχει εγκαταληφθεί, εξαιτίας της ανακάλυψης του φαινοµένου «επίδραση του µητρικού υλικού» ("matrix effect"), το οποίο οδηγεί άλλοτε σε υποβάθµιση (suppression) και άλλοτε σε ενίσχυση (enhancement) του σήµατος MS ενός συστατικού σε µητρικό υλικό, σε σχέση µε ένα πρότυπο διάλυµα.…”