Calcination enhances the aflatoxin and zearalenone binding efficiency of a Tunisian clay

Clays are known to have promising adsorbing characteristics, and are used as feed additives to overcome the negative effects of mycotoxicosis in livestock farming. Modification of clay minerals by heat treatment, also called calcination, can alter their adsorption characteristics. Little information, however, is available on the effect of calcination with respect to mycotoxin binding. The purpose of this study was to characterize a Tunisian clay before and after calcination (at 550 degrees C), and to investigate the effectiveness of the thermal treatment of this clay on its aflatoxin B1 (AFB1), G1 (AFG1), B2 (AFB2), G2 (AFG2), and zearalenone (ZEN) adsorption capacity. Firstly, the purified clay (CP) and calcined clay (CC) were characterized with X-ray Fluorescence (XRF), X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR-IR), cation exchange capacity (CEC), specific surface area (S-BET), and point of zero charge (pH(PZC)) measurements. Secondly, an in vitro model that simulated the pH conditions of the monogastric gastrointestinal tract was used to evaluate the binding efficiency of the tested clays when artificially mixed with aflatoxins and zearalenone. The tested clay consisted mainly of smectite and illite. Purified and calcined clay had similar chemical compositions. After heat treatment, however, some changes in the mineralogical and textural properties were observed. The calcination decreased the cation exchange capacity and the specific surface, whereas the pore size was increased. Both purified and calcined clay had a binding efficacy of over 90% for AFB1 under simulated poultry GI tract conditions. Heat treatment of the clay increased the adsorption of AFB2, AFG1, and AFG2 related to the increase in pore size of the clay by the calcination process. ZEN adsorption also increased by calcination, albeit to a more stable level at pH 3 rather than at pH 7. In conclusion, calcination of clay minerals enhanced the adsorption of aflatoxins and mostly of AFG1 and AFG2 at neutral pH of the gastrointestinal tract, and thus are associated with protection against the toxic effects of aflatoxins

Cross-talk between Fusarium verticillioides and Aspergillus flavus in vitro and in planta

Background: Driven by increasing temperatures and the higher incidences of heat waves during summer, an increased incidence of Aspergillus flavus next to Fusarium verticillioides in European maize can be expected. In the current study, we investigate the interaction between both species. Methods: Colonies of A. flavus/F. verticillioides were grown in a single culture, in a dual culture, and in a mixed culture. On daily basis, the mycelium growth of both pathogens was measured. After seven days the fumonisins and aflatoxins were extracted and quantified by LC-MS/MS. Results: The growth rate of A. flavus and F. verticillioides grown in dual or mixed culture with the other species was clearly slower compared to the growth rate in a single culture. Mycotoxin production was in most cases negatively affected by dual or mixed inoculation. In planta, a dual inoculation resulted in reduced lesions of A. flavus, whereas the lesion size and toxin production of F. verticillioides were unaffected in presence of A. flavus. The lesions as a result of a mixed inoculation were 112 % bigger than a single A. flavus inoculation and 9 % smaller than a single F. verticillioides inoculation. The fumonisin levels were 17 % higher compared to a single inoculation. In case A. flavus was present two days before F. verticillioides, the lesion size of F. verticillioides was 55 % smaller compared to a single F. verticillioides inoculation and fumonisin production was almost completely inhibited. Conclusion: The interaction between A. flavus and F. verticillioides is highly dynamic and depends on the experimental conditions, on the variable measured, and on the way, they colonize the host, in two inoculation points, simultaneously in one inoculation point, or sequentially one species colonizing an existing lesion made by the other

Monitoring the benzene contents in soft drinks using headspace gas chromatography-mass spectrometry: A survey of the situation on the Belgian market

Whenever benzoic acid is combined with ascorbic acid in acidic beverages such as soft drinks, benzene can be formed. To determine the current situation on the Belgian market, a headspace gas chromatographic mass spectrometric method was developed, which needs little to no sample preparation. This method was then used to analyze 134 soft drinks sampled on the Belgian market by the Federal Agency for the Safety of the Food Chain. Thirty-three percent of the samples contained no detectable benzene, whereas the majority of the samples (47%) contained trace amounts below the limit of quantification of the method (0.3 mu g L-1). Ten samples were above the European limit for benzene in drinking water of 1 mu g L-1, and one sample had a concentration of 10.98 mu g L-1, thereby exceeding the action limit for benzene in soft drinks of 10 mu g L-1 discussed at the Standing Committee on the Food Chain and Animal Health of the European Commission. Statistical analyses revealed that besides benzoic acid, ascorbic acid, and acidity regulators, the packing may also play an important role in benzene formation

Cross-talk between Fusarium verticillioides and Aspergillus flavus in vitro and in planta

Driven by increasing temperatures and the higher incidences of heat waves during summer, an increased incidence of Aspergillus flavus next to Fusarium verticillioides in European maize can be expected. In the current study, we investigated the interaction between both species. Colonies of A. flavus/F. verticillioides were grown in a single culture, in a dual culture, and in a mixed culture. The growth rate of A. flavus and F. verticillioides grown in a dual or mixed culture with the other species was clearly slower compared to the growth rate in a single culture. Mycotoxin production was in most cases negatively affected by dual or mixed inoculation. In planta, a dual inoculation resulted in reduced lesions of A. flavus, whereas the lesion size and toxin production of F. verticillioides were unaffected in the presence of A. flavus. The lesions as a result of a mixed inoculation were 112% bigger than a single A. flavus inoculation and 9% smaller than a single F. verticillioides inoculation. The fumonisin levels were 17% higher compared to a single inoculation. In case A. flavus was present two days before F. verticillioides, the lesion size of F. verticillioides was 55% smaller compared to a single F. verticillioides inoculation, and fumonisin production was almost completely inhibited. The interaction between A. flavus and F. verticillioides is highly dynamic and depends on the experimental conditions, on the variables measured and on the way they colonize the host, in two inoculation points, simultaneously in one inoculation point, or sequentially one species colonizing an existing lesion made by the other

Investigation into the possible natural occurence of semicarbazide in Macrobrachium rosenbergii prawns

In the past year there has been an increased incidence in Belgium of cases of positive semicarbazide (SEM) tests in imported freshwater Macrobrachium rosenbergii prawns, seemingly indicating the possible abuse of nitrofurazone, a banned antimicrobial agent. This was in contrast to all other European countries where no significant increase in SEM-positive samples was detected. A possible explanation for this discrepancy between Belgium and the other European Union member states could be the fact that only in Belgium were whole prawns (meat + shell) analyzed for the presence of tissue-bound metabolites of nitrofurans, whereas in the other countries only the edible part (meat) of these prawns was analyzed. To investigate the possible natural occurrence of SEM in freshwater prawns, an animal trial was set up. In this experiment two groups of 10 juvenile M. rosenbergii, previously raised under standardized laboratory conditions, were stocked into two separate aquaria, a control group under reference conditions (no addition of nitrofurazone) and a group exposed to a daily dose of 50 mg of nitrofurazone L-1 of culture water. Results of this animal trial proved that SEM naturally occurs in M. rosenbergii prawns but that at the current minimum required performance limit (MRPL) no tissue-bound SEM can be found in the meat of nontreated animals. In addition to this animal trial, commercial samples of other crustacean species, the shell and meat of which were analyzed separately, were also analyzed for the presence of SEM