The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature

Almonds are susceptible to infestation by <i>Aspergillus flavus</i>, an aflatoxin-producing fungus. The objective of this study was to investigate the effects of kernel type (inshell, shelled and split almonds) on the ability of <i>A. flavus</i> to grow and produce aflatoxins...

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Main Authors: Barbara Szonyi, Guangwei Huang, Tim Birmingham, Dawit Gizachew
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Toxins
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Online Access:https://www.mdpi.com/2072-6651/16/11/493
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author Barbara Szonyi
Guangwei Huang
Tim Birmingham
Dawit Gizachew
author_facet Barbara Szonyi
Guangwei Huang
Tim Birmingham
Dawit Gizachew
author_sort Barbara Szonyi
collection DOAJ
description Almonds are susceptible to infestation by <i>Aspergillus flavus</i>, an aflatoxin-producing fungus. The objective of this study was to investigate the effects of kernel type (inshell, shelled and split almonds) on the ability of <i>A. flavus</i> to grow and produce aflatoxins at different combinations of temperature (20, 27 and 35 °C), water activity (0.85, 0.92, 0.95 and 0.98 a<sub>w</sub>) and incubation period (10, 20 and 30 days). There was no fungal growth at 0.85 a<sub>w</sub> on any of the kernel types. At 0.92 a<sub>w</sub>, only the split kernels supported growth and aflatoxin synthesis. The fungus was able to grow and produce aflatoxins on all three kernels at 0.95–0.98 a<sub>w</sub> and 20–35 °C. At 0.98 a<sub>w</sub>, high total aflatoxin concentrations (>300 µg/kg) were found on the shelled and split kernels at all temperatures. On the inshell nuts, the fungus produced up to 372 µg/kg of total aflatoxins at 0.98 a<sub>w</sub> and 27 °C. Regression analysis showed that significantly higher levels of aflatoxins were produced at 27 °C (as compared to at 20 and 35 °C) on shelled and split almonds. Incubation time was also a significant predictor of aflatoxin accumulation. The results of this study indicated that shipping almonds below 0.85 a<sub>w</sub> and reducing storage time would significantly decrease the risk of infestation and aflatoxin production by <i>A. flavus</i>.
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spelling doaj-art-e057f6518c294dc8b7d507f7e948ed8c2024-11-26T18:24:08ZengMDPI AGToxins2072-66512024-11-01161149310.3390/toxins16110493The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and TemperatureBarbara Szonyi0Guangwei Huang1Tim Birmingham2Dawit Gizachew3Department of Chemistry and Physics, Purdue University Northwest, Hammond, IN 46323, USAAlmond Board of California, 1150 Ninth St., Ste. 1500, Modesto, CA 95354, USAAlmond Board of California, 1150 Ninth St., Ste. 1500, Modesto, CA 95354, USADepartment of Chemistry and Physics, Purdue University Northwest, Hammond, IN 46323, USAAlmonds are susceptible to infestation by <i>Aspergillus flavus</i>, an aflatoxin-producing fungus. The objective of this study was to investigate the effects of kernel type (inshell, shelled and split almonds) on the ability of <i>A. flavus</i> to grow and produce aflatoxins at different combinations of temperature (20, 27 and 35 °C), water activity (0.85, 0.92, 0.95 and 0.98 a<sub>w</sub>) and incubation period (10, 20 and 30 days). There was no fungal growth at 0.85 a<sub>w</sub> on any of the kernel types. At 0.92 a<sub>w</sub>, only the split kernels supported growth and aflatoxin synthesis. The fungus was able to grow and produce aflatoxins on all three kernels at 0.95–0.98 a<sub>w</sub> and 20–35 °C. At 0.98 a<sub>w</sub>, high total aflatoxin concentrations (>300 µg/kg) were found on the shelled and split kernels at all temperatures. On the inshell nuts, the fungus produced up to 372 µg/kg of total aflatoxins at 0.98 a<sub>w</sub> and 27 °C. Regression analysis showed that significantly higher levels of aflatoxins were produced at 27 °C (as compared to at 20 and 35 °C) on shelled and split almonds. Incubation time was also a significant predictor of aflatoxin accumulation. The results of this study indicated that shipping almonds below 0.85 a<sub>w</sub> and reducing storage time would significantly decrease the risk of infestation and aflatoxin production by <i>A. flavus</i>.https://www.mdpi.com/2072-6651/16/11/493aflatoxinsalmonds<i>Aspergillus flavus</i>mycotoxinsnuts
spellingShingle Barbara Szonyi
Guangwei Huang
Tim Birmingham
Dawit Gizachew
The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
Toxins
aflatoxins
almonds
<i>Aspergillus flavus</i>
mycotoxins
nuts
title The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
title_full The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
title_fullStr The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
title_full_unstemmed The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
title_short The Effects of Kernel Type (Inshell, Shelled and Split Almonds) on the Growth and Aflatoxin Production of <i>A. flavus</i> Under Different Combinations of Water Activity and Temperature
title_sort effects of kernel type inshell shelled and split almonds on the growth and aflatoxin production of i a flavus i under different combinations of water activity and temperature
topic aflatoxins
almonds
<i>Aspergillus flavus</i>
mycotoxins
nuts
url https://www.mdpi.com/2072-6651/16/11/493
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