Fungal strains and the development of tolerance against natamycin.

Antimicrobial resistance is a relevant theme with respect to both antibacterial and antifungal compounds. In this study we address the possible development of tolerance against the antifungal food preservative natamycin. A selection of 20 fungal species, originating from a medical as well as a food product context, was subjected to increasing concentrations of natamycin for prolonged time, a procedure designated as "training".

The decarboxylation of the weak-acid preservative, sorbic acid, is encoded by linked genes in Aspergillus spp.

The ability to resist anti-microbial compounds is of key evolutionary benefit to microorganisms. Aspergillus niger has previously been shown to require the activity of a phenylacrylic acid decarboxylase (encoded by padA1) for the decarboxylation of the weak-acid preservative sorbic acid (2,4-hexadienoic acid) to 1,3-pentadiene. It is now shown that this decarboxylation process also requires the activity of a putative 4-hydroxybenzoic acid (3-octaprenyl-4-hydroxybenzoic acid) decarboxylase, encoded by a gene termed ohbA1, and a putative transcription factor, sorbic acid decarboxylase regulator, encoded by sdrA.

A rapid microbial inhibition-based screening strategy for fluoroquinolone and quinolone residues in foods of animal origin.

A rapid, high-throughput antimicrobial screening assay for the detection of fluoroquinolone and 4-quinolone residues in foods of animal origin has been developed in ampoule format. The assay employs a single Escherichia coli species sensitive to those Gram-negative inhibitiory antimicrobial compounds and is presented in a comparable format to the existing commercially available Premi Test and Delvotest ampoule-based microbial inhibition tests (DSM, Delft, The Netherlands). In the novel E.