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[en] Between 2002 and 2003, an outbreak of a trout's mass death occurred at the intensive fish culture a Peruvian rural town (Marcara, Huaraz, Peru) where 15,000 from 20,000 fish died. Our objective in the present study was to investigate the high mortality of the trout biomass occurred in period of two months. This study was conducted after the peak of the outbreak has occurred. We collected samples of fishes, water and fish foodstuff which were examined for aflatoxin, metals, toxics and bacteria. We interviewed people who administered the feed pellet. Feed sample preparation, transport and storage. The processing of fish feed was at room temperature which was below 16 deg C. Once prepared the diet it was keep under an appropriate room for a few days before sending to Marcara town. Fishes. 20,000 immature trout larval of rainbow trout (Oncorhynchus mykiss) was acquired from an official Peruvian fish culture. The fishes were fed twice a day. Adjusted of feed ration was based from the monthly sample weight. Pellet sample analysis. The samples were analyzed for aflatoxin Bl (AFB1) according to the method previously published. The sensitivity is 0.1 μg per 1 kg of sample. During the fish development until the peak of the outbreak, the foodstuff to fishes was maintained in plastic bags. At this time the storage room temperature was 18-20 deg. C between 1.00-2.00 P.M. and the humidity rose close to 90 % at the Marcara facilities. Mortality development and Effect on survival. The fishes maintained in 4 pods had a normal surviving until end of November, less than 10 specimen dead by month. The fish outbreaks started the first week of December and continuing until the fourth week of January totalizing 15,000 dead fish from 20,000. The survival of the fish at the first month was less than 50 %. The mortality continues throughout January totalizing 15,000 dead fish and leaving only 25% survival. Laboratory data. The collected samples for analysis were frozen and transported in dry ice to the analysis laboratory. We took the samples on January 23 and it was analyzed on January 25. Aflatoxin Bl was detected in three samples of fish muscle and in the 3 samples of fish feed but it was negative in the 3 water samples. The AFB1 concentration was 10 times in the fish feed than in the fish muscle. In spite of heavy metal residues (lead, mercury and arsenic) were found in the fish samples, those concentrations were below the permissible levels. Volatile toxic residues were negative in water, fish and feed. Only the fish feed samples were contaminated by bacteria (Staphylococcus aureaus). Under favourable conditions of temperature and humidity, the Aspergillus flavus grows on certain foods and feeds, resulting in the production of aflatoxin Bl. For the trout, the highest admissible amount of AFBI in feed is 0.1 μg per kg. The data showed suggest that an improper handling of fish foodstuff (18-20 deg. C and 90 % humidity) was the cause growing of mould and/or spores and consequently it produced an increased concentration of AFBI in fish feed. Liver is strategically located between intestinal tract and general circulation. As AFBI concentration ranged in liver between 10 and 100 ppb, this level is capable to produce an acute hepatotoxicity in the fish stocks. (author)
[en] Effect of gamma-ray on the destruction of aflatoxin in peanut were studied. Forty peanut samples available in the market from different parts of the country were inoculated with A. flatus. After incubation at room temperature for a certain period of time, the inoculated peanut samples were irradiated with 6.4 kGy dose. The concentration of aflatoxin B1 in irradiated and non irradiated samples were determined. It was found that there was no significant differences on the average concentration of aflatoxin B1 between irradiated and non-irradiated samples. Furthermore, the concentration of aflatoxin B1 in 22 out of 40 peanut samples (55 per mille) were varied from 0 to 4834 ppb and mostly (42.5 per mille) found above the level of the standard value. Maximum microbial load and aflatoxin concentration were found on 9 day of incubation, approximately 1.04 x 1010 colonies and 1200 ppb respectively
[en] Highlights: • A versatile aptasensor was developed for simultaneous detection of OTA and AFB1. • This aptasensor has a wide detection range and low detection limit of pg mL-1 level. • The operation process is simple and convenient by using magnetic separation. • This strategy provides a new avenue for high throughput screen of multi-mycotoxins. - Abstract: Development of an efficient method for the simultaneous detection of two highly concerning mycotoxins, ochratoxin A (OTA) and aflatoxin B1 (AFB1), is of great significance on food safety monitoring. Herein, a magnetically controlled fluorescence aptasensor for simultaneous determination of OTA and AFB1 has been successfully developed. The working principle of the aptasensor is based on the specific aptamer-mycotoxin recognition and further leads to the partial release of two distinguishable fluorescence labels from the magnetic carriers. Through the magnetic separation, the reporter probes in the supernatant solution can be collected and converted into a sensitive fluorescence signal with dual emission peaks. This aptasensor provided a wide detection range of 2 pg mL-1 - 5 ng mL-1 for OTA and 5 pg mL-1 - 10 ng mL-1 for AFB1. The new easy-to-wash and simple-to-use approach offers a simultaneous and high selective detection with high sensitivity (limits of detection of 0.67 and 1.70 pg mL-1 for OTA and AFB1, respectively). Remarkable accuracy (relative standard deviation < 5.6%) during the mycotoxins determination as well as excellent quantitative recoveries (95–108%) during the analysis of the spiked corn samples were also achieved. This simple aptasensing scheme provides a new avenue for high throughput screen of dual mycotoxins due to its simple manipulation, short assay times, high selectivity and sensitivity.
[en] The aflatoxin M1 content in samples of commercial milk as well as in milk directly from farms in Western Slovakia was determined by radioimmunoassay using a commercial Czechoslovak RIA kit. In 25 analyzed samples of commercial milk the limit of 0.1 μg kg-1 aflatoxin M1 was not exceeded. From 110 sample from milk farms, 93 samples (84.5%) contained less than 0.1 μ kg-1 aflatoxin, for 15 samples (13.6%) the content ranged between 0.1 and 0.5 μg kg-1, and 2 samples contained 0.5 to 1.0 μg kg-1 of aflatoxin M1. (author). 2 figs., 20 refs
[en] Studies concerning mycotoxins involve activities of relevant potential for furthering knowledge in the fields of toxicology and environmental analysis. Using bioanalytical methods (biosensors, histochemistry), the conducted research aims at contributing to raising the awareness of local, national, and international media in relation to the safety of obtaining and processing vegetal and animal foods, by analyzing the possible effects of aflatoxins and ochratoxins, promoting animal health, food hygiene, in view of ensuring animal and human health. The study using laboratory animals (mice) while being part of one of the current national research directions, also holds international priority, by its contribution to a better understanding of several fundamental mechanisms of life at molecular level and to the characterization of certain biological processes that appear in mycotoxicosis.
[en] The method is applicable to the determination of aflatoxin B1 in malting barley, malt and cereals in general; it can serve as an expeditious screening method. The principles, instrumentation and chemicals as well as the working procedure are described. The detection limit is 1 μg/kg, recovery (at 5 μg/kg) is 0.85 ± 0.10. (Z.S.)
[en] The aim of this study was to evaluate productivity parameters and carcass yield of broiler chickens fed irradiated corn contaminated with mycotoxins. For this purpose, 180 one-day-old male chicks were divided into nine treatments and fed for 42 days. The results indicated that irradiation of corn with 5 kGy improved the productivity parameters studied. Therefore, gamma radiation may become an alternative for the control of the deleterious effects of mycotoxins on broiler chickens, which cause marked economic losses for rural producers.
[en] The outcome of the research project 'Modernization of Analytical Methods for the Determination of Contaminants and Additives in Foods', Part I of this laboratory manual summarizes 24 analytical methods for the determination of residues of pesticides, additives used in the food industry, toxic metals, nitrates and nitrites, aflatoxins, and other contaminants. Two of the methods are based on radioimmunoanalysis. (Z.S.)
[en] Highlights: • A novel QB-based ICA with two test lines was developed for the accurately quantitative detection of AFB1 and ZEN. • The SA-biotin system was innovatively introduced as the signal output of the C line instead of anti-mouse IgG antibodies. • This work can serve as a reference for the sensitive and accurate detection of multiple targets simultaneously. - Abstract: Immunochromatographic assay (ICA) is a promising technology for on-site detection. Nonetheless, the wide-scale application of ICA is hindered by several disadvantages, such as poor reproducibility, low sensitivity, and single-target detection. Thus, a novel quantum dot nanobead (QB)-based multiplexed ICA (QB-ICA) with multiple test lines was developed in this study for the simultaneous quantitative detection of aflatoxin B1 (AFB1) and zearalenone (ZEN), where QBs with high luminescence were used as labels to enhance the analytical sensitivity of the ICA. Moreover, a streptavidin (SA)-biotin system, which was undisturbed by the target mycotoxins, was introduced as the signal output for the control line. Consequently, stable and reliable T/C values (ratios of signals on the test line to that of the control line) were obtained as quantitative signals. The proposed QB-ICA demonstrated high sensitivity for the simultaneous detection of AFB1 and ZEN, of which the half-maximal inhibitory concentrations reached as low as 38.98 pg mL-1 and 1.23 ng mL-1, respectively. At 10% competitive inhibition concentration, the limit detections (LOD) were 1.65 and 59.15 pg mL-1 for AFB1 and ZEN, respectively. The average recoveries of the intra- and inter-assays ranged from 81.77% to 119.70% and from 94.18% to 111.4% for AFB1 and ZEN quantification, respectively, and the variation coefficients were less than 12%, thereby indicating that the proposed method is highly accurate and robust. These findings suggest that QB-ICA using SA-biotin system as the signal output of control line is an excellent point-of-care platform for the rapid screening of mycotoxins.