Ochratoxin A (OTA) produced by mycotoxigenic fungi (Aspergillus and Penicillium spp.) is an extremely toxic and carcinogenic metabolite. The use of cold plasma to inhibit toxin-producing microorganisms in coffee could be an important alternative to avoid proliferation of mycotoxigenic fungi. Roasted coffee samples were artificially inoculated with A. westerdijikiae, A. steynii, A. versicolor, and A. niger, and incubated at 27 °C over 21 days for OTA production. Samples were cold plasma treated at 30 W input power and 850 V output voltage with helium at 1.5 L/min flow. OTA production in coffee was analyzed by high performance liquid chromatography coupled to a mass spectrometer (HPLC-MS). After 6 min of treatment with cold plasma, fungi were completely inhibited (4 log reduction). Cold plasma reduces 50% of OTA content after 30 min of treatment. Toxicity was estimated for extracts of artificially contaminated roasted coffee samples using the brine shrimp (Artemia salina) lethality assay. Toxicity for untreated roasted coffee was shown to be “toxic”, while toxicity for cold plasma treated coffee was reduced to “slightly toxic”. These results suggested that cold plasma may be considered as an alternative method for the degradation and reduction of toxin production by mycotoxigenic fungi in the processing of foods and feedstuffs.
1 October 2017 in Journal of microbiology, biotechnology and food sciences
Human milk banks pasteurize and freeze the milk in order to conserve it, but thawing and prolonged storage cause loss of nutritional components. The aim of this work was to evaluate the effect of pasteurization, high hydrostatic pressures, UV radiation, and spray drying in human milk packed and stored at 25 to 40°C by a period of 14 weeks, using an accelerated shelf life method with Arrhenius model. Effectiveness of packaging, microbiological viability, and deterioration of carbohydrates, lipids, and proteins was evaluated. The results showed that proteins and carbohydrates in powdered human milk with different treatments did not show significant changes during storage at 25 to 40°C and without the growth of microorganisms. However, 33.3% deterioration of lipid oxidation was observed up at 40°C. We predict with the applied model that, at 18°C, the human milk powder will be preserved for approximately one year without significant changes in its composition.