Fungi are common spoilers of intermediate moisture foods such as bakery products. Brioche are bakery products prone to fungal spoilage due to their pH (5.8-6.2) and water activity (aw) (0.82-0.84). The aims of the present study were: (i) the identification of fungal species occurring in brioche products, (ii) the in vitro assessment of their growth potential, and (iii) the development of a validated growth model following the gamma concept. A total of 102 fungal strains were isolated, with Penicillium sp., Cladosporium sp., and Aspergillus sp. being the main genera, representing 90% of the isolates. Given the isolation frequency, any potential fungal prevalence throughout the bakery processs and/or the results of in vitro assessment of fungal growth potential under conditions mimicking brioche (pH, aw, temperature), Aspergillus flavus, Aspergillus fumigatus, and Penicillium sp. were selected for the development of the gamma model. According to in vitro validation, the model successfully predicted fungal growth, while on in situ experiments, the intrinsic parameters (aw and/or level of used preservative) of brioche in combination with packaging conditions (modified atmosphere) did not allow fungal growth.

Fungi assisted microalgae bioflocculation is an emerging, efficient and cost-effective microalgal harvesting method, but no study has systematically evaluated and compared fungal spore-assisted (FSA) and fungal pellet-assisted (FPA) microalgal harvesting methods. In this study, harvesting Chlorella sp. cells by co-culture with Penicillium sp. spores or pellets was compared. Temperature, glucose concentration, pH and fungi:algae ratio were the critical parameters for harvesting efficiency. The highest flocculation efficiency (99%) of FSA method was achieved in 28 h at 40 °C, 160 rpm, 5 g glucose/L and 1.1 × 104 cells/mL (spore). FPA method can harvest 98.26% algae cells in 2.5 h at 34 °C, 160 rpm, pH 4.0 with the fungi:algae ratio of 1:2. The carbon input for FPA is only half of that for FSA. FPA takes less time and needs less glucose input compared with FSA and may be more promising to be further developed as an effective microalgae bioflocculation method.

Six laboratory experiments were carried out to investigate the effect of the fungicide Benomyl on pure cultures of some plant growth promoting bacteria (PGPB) and some fungi. The highest LD50 was recorded for Bacillus circulans and proved to be the most resistant to the fungicide, followed by Azospirillum braziliense, while Penicillium sp. was the most affected microorganism. LD50 values for the affected microorganisms were in 21-240 orders of magnitude lower in comparison with the LD50 value for Azospirillum braziliense. The results indicate a strong selectivity for Benomyl against Rhizobium meliloti and Penicillium sp. when compared to other microorganisms tested. The highest safety coefficient was recorded for Bacillus circulans followed by Azospirillum braziliense, while Rhizobium meliloti, showed the lowest safety coefficient value compared to other bacteria. The lowest toxicity index was recorded for Bacillus circulans and Azospirillum braziliense. The slope of the curves for Bacillus sp. and Rhizobium meliloti was steeper than that of the other curves, suggesting that even a slight increase of the dose of the fungicide can cause a very strong negative effect. In conclusion, Benomyl could be applied without restriction when using inocula based on growth promoting bacteria such as symbiotic nitrogen fixers (Rhizobium meliloti), non-symbiotic nitrogen fixers (Azospirillum braziliense) or potassium solibilizers (Bacillus circulans), given that the fungicide is applied within the range of the recommended field dose.