Potential for Control of A. Flavus and Aflatoxin B₁ in Vitro and in Stored Egyptian Shelled Peanuts using Gaseous Ozone Treatment

Yousef Sultan^1,2, Naresh Magan¹*

(1. Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Beds., MK43 0AL, U.K.; 2.Department of Food Toxins and Contaminants, National Research Centre, Dokki, Cairo 12622, Egypt.)

Abstract: The objective of this study was to examine the effect of gaseous ozone (O₃) on (a) germination, (b) mycelial growth, (c) aflatoxin B₁ (AFB₁) production by strains of Aspergillus flavus at different water activity (a_w, 0.89~0.97=13.1%~24% moisture content) and 25 ^oC in vitro. In addition, taking Egyptian peanuts as a research object, shelled peanuts at 0.93 a_w were inoculated with two concentrations of A. flavus conidia (10³, 10⁵ conidia/g) and exposed to gaseous O₃ and then stored. In all cases, exposure was for 30 min at 6 L/min. Generally, >100 ppm O₃ significantly inhibited conidial germination of A. flavus strains (EGP-B07; SRRC-G 1907) on a defined yeast sucrose medium within 48 hrs. However, exposure of growing colonies of A. flavus to O₃ with up to 300 ppm, had no effect on subsequent colony extension. The same concentration significantly affected AFB₁ production, but only at 0.89 a_w. Populations of both A. flavus strains in stored shelled peanuts exposed at 0.93 a_w were significantly decreased at 100~400 ppm O₃. However, AFB₁ production was only significantly reduced in the 400 ppm O₃ treatments at both inoculum load levels. These results are discussed in the context of O₃ gas use for controlling A. flavus populations and AFB₁ in shelled peanuts post-harvest.
Key words: ozonation; Egyptian peanuts; storage; aflatoxins; germination; growth; toxin

Chinese Library Classification Number: TS201.1

Documentary Identification Code: A    Article ID: 1007-7561(2021)06-0038-08

Published time on CNKI: 2021-11-03 14:12:17

Published address on CNKI: https://kns.cnki.net/kcms/detail/11.3863.TS.20211102.1555.014.html