Evaluation of antifungal activity and cytotoxicity of additives used in agriculture and the food industry

Abstract

Food losses due to the presence of microorganisms, such as fungi, are a major concern worldwide, especially with a constantly growing worldpopulation. The development of these organisms leads to sensory defects in food ranging from visual deterioration to noticeable changes in smell, tasteor texture, but they can also have negative impacts on health due to the production of mycotoxins by some species. The objective of this work was toevaluate antifungal activity on fungi of the genus Aspergillus in the presence of Cu, Calcium Propionate and Potassium Sorbate, which are used asantifungals in agriculture and the food industry. The cytotoxicity also was evaluated. Fungi isolated and identified in previous work from spoiled breadwere used: Aspergillus niger and A. tritici. The proposed methodology included different concentrations of sodium propionate and sorbate (0.15?2 %w/v) in the presence of the microorganism under study in liquid Luria-Bertani (LB) culture medium. On the other hand, the antifungal activity ofdifferent additives was determined by measuring mycelial growth on extract-glucose agar (EG), with and without the additives. For the copper effect,a similar methodology with 400 ppm. For the cytotoxicity assay, Artemia salina eggs were incubated in saltwater at 27°C for 48 hours until the naupliihatched. The nauplii were exposed to the additive solution. The results showed inhibition of the growth of both fungi species with the different additivessolutions used. Propionate inhibited the growth of A. niger at a concentration of 2%, while for A. tritici was more resistant but a decrease in growthwas observed, compared to the positive control. With potassium sorbate it was observed that at concentrations of 0.5% and 1% no growth of A. nigerand A. tritici was observed, respectively. Finally, the experiments carried out in solid medium showed that A. niger did not showed mycelial growthin the presence of 1.5% calcium propionate and copper, while with potassium sorbate the growth was not significant. In cytotoxicity assay, copperpresented total inhibition and all nauplii died, followed by propionate y sorbate. These results shows that the additives are effective in fungi controllingin concentrations higher than those allowed by the argentine food code and they are cytotoxic, so it is important to look for other additives moreeffective and less toxic alternative.