Mitigation of nivalenol using alcoholic fermentation and magnetic field application.

This study aimed at evaluating mitigation of nivalenol (NIV) in alcoholic fermentation with magnetic field application (MF). Mitigation was related to both the glutathione (GSH) redox molecule and the enzyme peroxidase (PO), which were synthesized by Saccharomyces cerevisiae US-05. Conditions under evaluation were NIV (0.2 µg mL-1), MF application (35 mT) and simultaneous use of mycotoxin and MF. The GSH content and the PO activity were increased when the culture contained NIV and the alcohol profile was altered after 48 h of fermentation. At the end of the alcoholic fermentation, NIV was mitigated by 56.5%. Therefore, this process is a promising method to reduce contamination by NIV, although the mycotoxin affects the chemical characteristics of the final product.

Peroxidase as a simultaneous degradation agent of ochratoxin A and zearalenone applied to model solution and beer.

The aim of this study was to evaluate the action of the commercial peroxidase (POD) enzyme (Armoracia rusticana) on the simultaneous degradation of ochratoxin A (OTA) and zearalenone (ZEA) in model solution and beer. For this purpose, the reaction parameters for POD action were optimized, POD application in the degradation of mycotoxins in model solution and beer was evaluated and the kinetic parameters of POD were defined (Michaelis-Menten constant - KM and maximal velocity - Vmax). In the reaction conditions (pH 7, ionic strength of 25 mM, incubation at 30 °C, addition of 26 mM H2O2 and 1 mM potassium ion), POD (0.6 U mL-1) presented the maximum activity for simultaneous degradation of OTA and ZEA of 27.0 and 64.9%, respectively, in model solution after 360 min. The application of POD in beer resulted in the simultaneous degradation of OTA and ZEA of 4.8 and 10.9%, respectively. The kinetic parameters KM and Vmax for degradation of OTA and ZEA were 50 and 10,710 nM and 0.168 and 72 nM min-1, respectively. Therefore, POD can be a promising alternative to mitigate the contamination of OTA and ZEA in model solution and beer, minimizing their effects in humans.

Ochratoxin A reduction by peroxidase in a model system and grape juice.

This study aimed at evaluating the potential of the peroxidase (PO) enzyme to reduce ochratoxin A (OTA) levels and its application to grape juice. Both commercial PO and PO extracted from rice bran were evaluated, respectively, regarding their activity towards OTA in a model system. The affinity between PO and OTA was verified by the Michaelis-Menton constant and the maximum velocity parameters, resulting in 0.27 µM and 0.015 µM min-1 for the commercial enzyme, and 6.5 µM and 0.031 µM min-1 for PO extracted from rice bran, respectively. The lowest residual OTA levels occurred when 0.063 U mL-1 of the enzyme was applied. Under these conditions, the OTA reduction was 41% in 5 h for the commercial enzyme, and 59% in 24 h, for PO extracted from rice bran. When the extracted PO, with the activity of 0.063 U mL-1, was applied to whole grape juice, the OTA levels decreased to 17%, at 24 h. The capacity shown by PO for reducing OTA levels was confirmed in whole white grape juice, as a model system. This study may assist the wine industry to offer healthier products and add value to rice bran. Graphical abstract.

Aflatoxin M1 and B1 in Colombian milk powder and estimated risk exposure.

Aflatoxin M1 (AFM1) and aflatoxin B1 (AFB1) were determined in 51 milk powder samples purchased from different grocery stores located in the Caribbean region of Colombia. Analysis was conducted using QuEChERS extraction and high-performance liquid chromatography with fluorescence detection. Results from the analytical method showed recovery ranges from 65% to 110% and relative standard deviations lower than 20%. AFM1 was detected in 100% of the milk samples (0.20-1.19 µg/kg) and 55% exceeded the maximum level in milk (0.5 µg/kg) set by the Colombian and European regulations. AFB1 was not detected in any of the analysed samples. Considering the measured contamination the maximum AFM1 level that can be ingested by consumption of milk powder is 0.007-0.013 µg/person/day. These values are above the average dietary intake estimated in Latin America according to the Joint FAO/WHO Expert Committee, which is 0.0035 µg/person/day.