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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.

Several freeze-drying and spray-drying methods were investigated in relation to the retention of immunoglobulins (Ig) A, IgG and IgM. Spray drying produced human milk powders with 2% humidity and a good retention of IgG (>88%) and IgM (~70%).However, only 38% of IgA remained after spray-dying. For freeze-drying, only the highest heating plate temperature used in this study (40 o C) brought IgA content down to 55% in a powder with 1.75% residual humidity, whereas milk samples undergoing lower temperatures had higher preservation rates (75% for IgA and 80% for IgG and IgM) and higher residual moisture contents. From these results, it can be concluded that IgA is the most sensitive Ig lost during drying processing of human milk. The best method to generate human milk powders without a significant loss of Ig was thus freeze-drying at 30 o C heating plate temperature, which accelerated the process compared to lower processing temperatures, but still had good overall Ig retention.

In this research removal of NH-N, NO-N and PO-P nutrients from municipal wastewater was studied, using Chlorella vulgaris, Pseudomonas putida, Bacillus cereus and an artificial consortium of them. The objective is to analyze the performance of these microorganisms and their consortium, which has not been previously studied for nutrient removal in municipal wastewater. A model wastewater was prepared simulating the physicochemical characteristics found at the wastewater plant in Chapala, Mexico. Experiments were carried out without adding an external carbon source. Results indicate that nutrient removal with Chlorella vulgaris was the most efficient with a removal of 24.03% of NO-N, 80.62% of NH-N and 4.30% of PO-P. With Bacillus cereus the results were 8.40% of NO-N, 28.80% of NH-N and 3.80% of PO-P. The removals with Pseudomonas putida were 2.50% of NO-N, 41.80 of NH-N and 4.30% of PO-P. The consortium of Chlorella vulgaris-Bacillus cereus-Pseudomonas putida removed 29.40% of NO-N, 4.2% of NH-N and 8.4% of PO-P. The highest biomass production was with Bacillus cereus (450 mg/l) followed by Pseudomonas putida (444 mg/l), the consortium (205 mg/l) and Chlorella vulgaris (88.9 mg/l). This study highlights the utility of these microorganisms for nutrient removal in wastewater treatments.

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