Immunoaffinity Column Cleanup with Liquid Chromatography Using Post-Column Bromination for Determination of Aflatoxin B1 in Cattle Feed: Collaborative Study

A collaborative study was conducted to evaluate the effectiveness of an immunoaffinity column cleanup liquid chromatography (LC) method for determination of aflatoxin B1 in cattle feed at a possible future European regulatory limit (1 ng/g). The test portion was extracted with acetone–water (85 + 15), filtered, diluted with water, and applied to an immunoaffinity column. The column was washed with water to remove interfering compounds, and the purified aflatoxin B1 was eluted with methanol. Aflatoxin B1 was separated and determined by reversed-phase liquid chromatography (RP–LC) and detected by fluorescence after post column derivatization (PCD) involving bromination. PCD was achieved with either pyridinium hydrobromide perbromide (PBPB), used by 14 laboratories, or an electrochemical cell and addition of bromide to the mobile phase, used by 7 laboratories. Both derivatization techniques were not significantly different when compared by the t-test; the method was statistically evaluated for all laboratories together (bromination and PBPB). The cattle feed samples, both spiked and naturally contaminatedwithaflatoxinB1, were sent to 21 laboratories in 14 different countries (United States, Japan, and Europe). Test portions were spiked at levels of 1.2 and 3.6 ng/g for aflatoxin B1. Recoveries ranged from 74 to 157%. Based on results for spiked samples (blind pairs at 2 levels) as well as naturally con-taminated samples (blind pairs at 3 levels), the relative standard deviation for repeatability (RSDr) ranged from 5.9 to 8.7%. The relative standard deviation for reproducibility (RSDR) ranged from 17.5 to 19.6%. The method showed acceptable within-and between-laboratory precision for this matrix, as evidenced by HORRAT values, at the target levels of determination for aflatoxin B1. No major differences in RSD were observed, showing that the composition of the feeds was not a factor for the samples tested and that the method was applicable for all materials used.

European survey on sterigmatocystin in cereals, cereals-based products, beer and nuts

Based on the EFSA proposal ‘Survey on sterigmatocystin in food’ (GP/EFSA/CONTAM/2013/02), this study provides a survey on the occurrence of this mycotoxin. A total of 1,259 samples of cereal grains (429), cereal products (713), beer (53) and nuts (64) were analysed for the presence of sterigmatocystin (STC). Samples were mainly collected at processing plants, storage facilities, wholesale and retail between August 2013 and November 2014, in nine European countries, mostly Greece, Italy, the Netherlands and the United Kingdom. The products originated from 27 European countries and 18 other countries. All samples were analysed by methods based on liquid chromatography coupled with tandem mass spectrometry. The limit of quantification (LOQ) was 0.5 µg/kg and the limit of detection (LOD) was in the range 0.05-0.15 µg/kg (0.005-0.01 µg/l for beer). Overall, STC was identified in 10% of the samples; it was not detected in either beer or nut samples. More than 50% of the contaminated samples contained levels between LOD and LOQ; in the other cases, levels were between 0.5-6 µg/kg with one exception (33 µg/kg in oats). In cereal grains, rice and oats seemed the cereals most prone to STC contamination (100% unprocessed rice, 22% oats grains); however the number of rice samples was limited (n=28) and the samples were collected almost exclusively in Italy and Greece. In cereal products, levels were lower than in cereal grains. The highest incidence was in processed rice (21%) and breakfast cereals (19%), while for the other cereal products this was between 5-7%. In the contaminated cereal products, rice and oats were often present as ingredients.

Novel sampling methods for the analysis of mycotoxins and the combination with spectroscopic methods for the rapid evaluation of deoxynivalenol contamination

A novel non-destructive sampling approach is described for the identification of food matrices contaminated with deoxynivalenol and other mycotoxins. This technique is different from currently applied sampling procedures for this purpose and is based on the principle that surface material from the tested goods is collected on a filter and brought to chemical or spectroscopic analysis. This approach has been applied to several matrices and mycotoxins, with a focus on those mycotoxin-matrix combinations that are of main relevance due to current or future legislation. Tests were carried out with a facility that has been shown to be suitable to process large quantities of materials at points of transaction, such as harbour. Further experiments with a small sampling lance prototype showed that analytical results from the chemical analysis of the tested goods can be correlated with the results obtained with this novel sampling procedure.