Sara Antoniazzi

Aflatoxin accumulation in whole crop maize silage as a result of aerobic exposure

BACKGROUND Most of the maize silage stored in horizontal silos is exposed to air and can be spoiled by fungi. Potentially toxigenic fungi have been found in maize silage, and about 300 mycotoxins have been detected. Among these mycotoxins, the most harmful for feed and food safety are aflatoxins. The aim of the study was to set up a specific method to detect aflatoxins in maize silage, and to investigate whether aflatoxin contamination in maize silage depends on the level of field contamination of the crop, and whether the occurrence of aerobic spoilage during ensiling has any effect on the final contamination of the silage. RESULTS A method for the determination of aflatoxin B(1), B(2), G(1) and G(2) in maize silage using high-performance liquid chromagraphy with fluorescence detection has been developed and validated. Recoveries of aflatoxin B(1), B(2), G(1), and G(2) spiked over the 0.25 to 5 µg kg(-1) range averaged 74-94%. The results of laboratory scale and farm scale ensiling experiments indicated that aflatoxins could increase when silage is exposed to air during conservation or during the feed-out phase. CONCLUSIONS The method here proposed to detect aflatoxins in silages has proved to be sensitive and is able to detect levels of 0.1 and 0.5 ng mL(-1) for AFB(1) and AFG(1), and between 0.025 and 0.125 ng mL(-1) for AFB(2) and AFG(2). This study also provides evidence of aflatoxin accumulation in whole crop maize silage as a result of aerobic exposure.

A survey on the occurrence of ochratoxin A in feeds and sera collected in conventional and organic poultry farms in Northern Italy

Abstract A survey has been conducted on conventional and organic poultry farms located in northern Italy in order to investigate the occurrence of ochratoxin A (OTA) in feeds and sera in 2006. Ten poultry farms were monitored by taking 20 samples of feed and 94 samples of blood. OTA was assessed through immunoaffinity column purification and HPLC analysis. For in-house validation, recovery experiments, carried out on the spiked samples in the range of 1.0-10.0 μg OTA kg-1 and 0.3-3.0 ng OTA ml-1 for the feed and serum samples, respectively, led to overall recovery averages of 80.6% (RDS=7.3%, n=9) and 83.3% (RDS=3.1%, n=9), respectively. All the feed samples were contaminated by OTA with values ranging from 0.04 to 6.50 μg kg-1. Fiftythree percent of the sera samples were positive, with values ranging from 0.003-0.165 ng ml-1. None of the feed samples was above the limits set by the European Union on OTA contamination in poultry feeds. No statistically significant differences in OTA contamination of feed or sera were observed either between the organic vs conventional group or between the laying hens vs broiler group.

Zearalenone contamination in farm maize silage

Riassunto Contaminazione da zearalenone negli insilati aziendali di mais. Nell’ambito di un’indagine quadriennale sullo stato di conservazione degli insilati aziendali di mais in Piemonte, è stato valutato il livello di contaminazione da zearalenone (ZEA) nel foraggio all’insilamento e nei corrispondenti insilati. Per la determinazione del contenuto in zearalenone degli insilati, matrici acide e ricche di metaboliti di fermentazione, è stato necessario mettere a punto un protocollo specifico mediante determinazione in HPLC. Dai risultati emerge che la contaminazione di ZEA negli insilati può verificarsi in due momenti: sulla coltura in campo prima della trinciatura e nelle zone periferiche dei sili soggette a penetrazione di aria durante la fase di consumo. Le contaminazioni in campo tendono ad aumentare con raccolte tardive nella stagione autunnale. Negli insilati ben conservati e nelle aree centrali della maggior parte dei sili la contaminazione derivante dal campo non subisce variazioni, mentre si osservano aumenti di contenuto in ZEA nelle zone periferiche soggette a deterioramento aerobico.

A Preliminary Assessment of HTST Processing on Donkey Milk

Due to increasing attention from consumers on non-bovine milk types, and to the increase in the number of small dairy donkey farms in Italy, farmers require more advanced and reliable processing devices, in order to guarantee a safe product of high quality. To this aim, a new small-scale High-Temperature Short-Time (HTST) pasteurizer (72 °C for 15 s), prototyped by the authors, was tested on donkey milk. The efficacy of the HTST device was tested on raw donkey milk microflora by enumeration of total aerobic bacteria, Enterobacteriaceae and Bacillus cereus. The biochemical quality was assessed by determining the protein profile by monodimensional electrophoresis and by measuring lysozyme activity. The HTST apparatus was able to reduce the total bacteria count, and to completely eradicate Enterobacteriaceae. Bacillus cereus, when present, was decreased with low efficiency. Changes in the protein profile were observed in milk pasteurized in accordance with both processes, although HTST seemed to limit casein degradation. Lysozyme activity was not substantially affected in comparison to raw donkey milk. In conclusion, a tailored small-volume HTST device could be safely applied to pasteurize donkey milk in on-farm pasteurization processes on small dairy donkey farms.