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An improved analytical method for aflatoxin B1 (AFB1) and aflatoxin M1 (AFM1) determination in pig liver is described, using an aqueous methanol extraction, an immunoaffinity column clean-up step and a direct fluorometric measurement for toxin detection and quantification. A detection limit of 1.0 microg kg-1 was achieved for AFB1 and AFM1. Mean recoveries of 80.7+/-9.0% for AFB1 spiked at 1.0-9.7 microg kg-1 levels and of 76.7+/-6.6% for AFM1 spiked at 1.0-5.5 microg kg-1 levels were obtained. Recovery data for spiked samples were statistically compared with those obtained by the same extract using classical reversed-phase high-performance liquid chromatography (RP-HPLC) with fluorescence detection, showing a significant correlation (p

A simple and rapid method for the determination of ochratoxin A (OA) in ham was developed using a basic methanolic extraction, immunoaffinity column clean-up and a fluorometric determination of the toxin contamination levels. A mean recovery of OA from ham samples spiked at levels from 0.7 to 9.7 microg kg(-1) was 83 +/- 6% using the fluorometric method, with a detection limit of 0.7 microg kg(-1). Recovery data were compared statistically with those obtained using reversed-phase high-performance liquid chromatography with acetonitrile-water-acetic acid (99:99:2) as mobile phase and fluorescence detection, commonly used for OA determination in food. A good correlation between the two analytical techniques was obtained. Both methods were successfully applied to 42 ham samples, 21 in the middle of the ripening period (after 6 months from the process beginning) and the other 21 at the end of the maturation, after 12 months. Twenty-seven samples (64%) showed an OA contamination level <1.0 microg kg(-1), the Italian Ministry of Health guideline. The maximum contamination level found was 2.3 microg kg(-1). A good agreement (R(2) = 0.980) between HPLC and fluorometer analysis on naturally contaminated samples was obtained.

The aim of this research was to use a polyphasic approach to differentiate Penicillium verrucosum from Penicillium nordicum, to compare different techniques, and to select the most suitable for industrial use. In particular, (1) a cultural technique with two substrates selective for these species; (2) a molecular diagnostic test recently set up and a RAPD procedure derived from this assay; (3) an RP-HPLC analysis to quantify ochratoxin A (OTA) production and (4) an automated system based on fungal carbon source utilisation (Biolog Microstation™) were used. Thirty strains isolated from meat products and originally identified as P. verrucosum by morphological methods were re-examined by newer cultural tests and by PCR methods. All were found to belong to P. nordicum. Their biochemical and chemical characterisation supported the results obtained by cultural and molecular techniques and showed the varied ability in P. verrucosum and P. nordicum to metabolise carbon-based sources and to produce OTA at different concentrations, respectively. [ABSTRACT FROM AUTHOR]