Use of Natural Products on the Control of Aspergillus flavus and Production of Aflatoxins In Vitro and on Tomato Fruit

Abstract

Aspergillus flavus affects fresh and dry fruit and vegetable products, and its toxic metabolites, namely aflatoxins, cause serious damage in humans. The objective of this research study was to evaluate the effect of commercial natural products as well as edible and nanostructured chitosan coatings on the development of A. flavus and on the production of aflatoxins in vitro and in tomato. Treatments were as follows: chitosan 1%, chitosan coating, chitosan nanostructured coating, Citrocover 1% (citrus seed extract), Resinadher 0.5% (pine resin extract), mancozeb 2%, and water. The variables were as follows: halo inhibition, spore production, and aflatoxins content. In fruit, the following were evaluated: disease incidence, mycelial growth, and aflatoxin production. An ANOVA (Tukey: p < 0.05) was used. In vitro results showed that Citrocover and Resinadher reduced sporulation (0.2 and 0.9 × 105 spores mL−1, respectively), while chitosan inhibited the production of aflatoxins. With Resinadher and Citrocover, tomato fruit had the lowest incidence, mycelial growth, and aflatoxin production with corresponding values of 0%, 0.0 cm2, and 0.95 ppb, respectively, and 7%, 0.2 cm2, and 1.77 ppb, respectively. The use of Citrocover and Resinadher could be a viable alternative to decrease the development of A. flavus in tomato fruit.

Effect of Biodegradable Coatings on the Growth of Aspergillus flavus In Vitro, on Maize Grains, and on the Quality of Tortillas during Storage

“…Similar to our findings, in the above studies on figs and tomatoes, the final content of aflatoxins was considerably less than 20 ppb, a value permitted for agricultural edible products by the Food and Drug Administration [ 25 ]. In addition, there were no negative effects during fruit ripening, nor on the sensory and nutritional quality of figs and tomatoes [ 20 , 21 ].…”

“…For propolis (Rosa Elena Dueños S.A. de C.V. Mexico city, Mexico) and pine resin extract (MS Agros. Yautepec Morelos, Mexico), 1200 µL of the liquid extract of each compound was diluted in 400 mL of 30% ethanol and 240 µL of 0.05% Tween 20 solution [ 20 ].…”

“…To quantify aflatoxins, the methodology reported by Segura-Palacios et al [ 20 ] was followed. Ten grams of three tortilla samples taken at 0 and 21 storage days at 4 °C was macerated and 50 mL of 70% ethanol was added and mixed in a food processor (Oster, Mexico) for 30 s at 10,000 RPM.…”

“…With respect to natural compounds, it has been demonstrated that formulations alone or combined based on propolis (a resinous compound created by bees that is rich in active compounds such as flavonoids, phenolic acids, and terpene derivatives) [ 16 ], chitosan (a polysaccharide obtained from partially deacetylated chitin) [ 17 , 18 ], and pine resin extracts (a plant secretion from tree bark, particularly of conifers) [ 19 ] provided an effective control over the development of A. flavus in vitro and of various horticultural products artificially infected by this fungus, including ficus and tomato [ 15 , 20 , 21 ]. In all of these studies, not only was the incidence of A. flavus disease notably reduced compared to the untreated ones but also the production of the aflatoxins was remarkably low with corresponding values less than 20 ppb.…”

Biological Control of Aspergillus flavus by the Yeast Aureobasidium pullulans In Vitro and on Tomato Fruit

“…These mycotoxins are mainly produced by A. flavus , A. parasiticus , and A. nomius [ 2 ]. A. flavus is especially problematic because of its ability to grow on various substrates under different environmental conditions and the property to produce numerous spores that remain viable even under extreme conditions [ 3 ]. The entry of fungi into crops not only impairs the self-defense of crops by the fungal attack but also contaminates crop seeds, leading to the production of mycotoxins.…”