Effect of water activity and temperature on mycotoxin production by Alternaria alternata in culture and on wheat grain

Magan, Naresh; Cayley, G. R.; Lacey, J.

doi:10.1128/aem.47.5.1113-1117.1984

Cited by 105 publications

(47 citation statements)

References 28 publications

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“…However, the aflatoxin contents of the samples stored at 85 Ϯ 2% and 95 Ϯ 2% relative humidity decreased after the 15th day of storage (Tables 1 and 2). The effect on aflatoxin production of the different relative humidity levels was also reported by Magan et al (1984) and Gurses et al (2001). It was reported that the fluctuation in the amount of aflatoxin was caused by the decomposition of chemical structure of toxin and the dominance of other indigenous mold strain during storage (Gurses et al 2001).…”

Section: Aflatoxin Total Formation Potentialsupporting

confidence: 75%

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EFFECTS OF DIFFERENT STORAGE CONDITIONS ON AFLATOXIN FORMATION IN KÖME INOCULATED WITH ASPERGILLUS PARASITICUS NRRL 2999

Yıldız

Sert

Gürses

2008

Journal of Food Safety

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In this study, Köme with walnuts were investigated for aflatoxin production. One part of stringed walnuts was inoculated at 104 spores/g with the Aspergillus parasiticus NRRL 2999 strain, and the other as control group was not inoculated. The Köme samples were stored at 20 ± 1C at 85 ± 2% and 95 ± 2% relative humidity for 45 days. All the samples were subjected to aflatoxin B1 (AFB1) and total aflatoxin analysis in certain time intervals (1, 4, 7, 15, 30 and 45 days). Enzyme‐linked immunosorbent assay was used to detect the amounts of aflatoxins. At 85 ± 2% and 95 ± 2% relative humidity, the detected amounts of aflatoxins were 616.15 ng/kg AFB1 and 1747.16 ng/kg aflatoxin total, and 732.98 ng/kg AFB1 and 2039.02 ng/kg total at the end of 45 days, respectively. The findings of this research indicated that aflatoxin formation in Köme is dependent on the storage conditions, such as mold contamination, and relative humidity. Aflatoxin production was found in high levels at the 95 ± 2% relative humidity. PRACTICAL APPLICATIONS This study contributes to a better understanding of the effect on aflatoxin production of factors such as relative humidity and mold contamination. This approach is useful for determining storage conditions that would prevent aflatoxin formation.

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Section: Aflatoxin Total Formation Potentialsupporting

confidence: 75%

“…Development of fungi is dependent on both abiotic and biotic variables. Perhaps the two most important environmental factors are substrate water activity and temperature (Magan et al 1984).…”

Section: Introductionmentioning

confidence: 99%

EFFECTS OF DIFFERENT STORAGE CONDITIONS ON AFLATOXIN FORMATION IN KÖME INOCULATED WITH ASPERGILLUS PARASITICUS NRRL 2999

Yıldız

Sert

Gürses

2008

Journal of Food Safety

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“…Fungal growth and mycotoxin production result from the complex interaction of several factors and, therefore, an understanding of each factor involved is essential for understanding the overall process and to predict and prevent mycotoxin development (Chamley et al 1994). Temperature and water activity (a W ) are the primary environmental factors that influence growth and mycotoxin production by several Alternaria species in cereals and oil seeds (Young et al 1980;Magan and Lacey 1984;Torres et al 1992;Etcheverry et al 1994;Magan and Baxter 1994).…”

Section: Introductionmentioning

confidence: 99%

Effect of environmental factors on tenuazonic acid production by Alternaria alternata on soybean-based media

Oviedo¹,

Ramírez²,

Barros³

et al. 2009

Journal of Applied Microbiology

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Aims: To determine the effects of water activity (aW; 0·995–0·90), temperature (5, 18, 25 and 30°C), time of incubation (7–35 days) and their interactions on tenuazonic acid (TA) production on 2% soybean‐based agar by two Alternaria alternata strains isolated from soybean in Argentina. Methods and Results: TA production by two isolates of A. alternata was examined under interacting conditions of aW, temperature and time of incubation on 2% soybean‐based agar. Maximum TA production was obtained for both strains at 0·98 aW, but at 30 and 25°C for the strains for RC 21and RC 39, respectively. The toxin concentration varied considerably depending on aW, temperature, incubation time and strain interactions. TA was produced over the temperature range from 5 to 30°C and aW range from 0·92 to 0·995, however at 5 and 18°C little TA was produced at aW below 0·94. Contour maps were developed from these data to identify areas where conditions indicate a significant risk for TA accumulation. Conclusions: The optimum and marginal conditions for TA production by A. alternata on soybean‐based agar were identified. The results indicated that TA production by A. alternata is favoured by different temperatures in different strains. Significance and Impact of the Study: Data obtained provide very useful information for predicting the possible risk factors for TA contamination of soybean as the aW and temperature range used in this study simulate those occurring during grain ripening. The knowledge of TA production under marginal or sub‐optimal temperature and aW conditions for growth are relevant as improper storage conditions accompanied by elevated temperature and moisture content in the grain can favour further mycotoxin production and lead to reduction in grain quality.

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“…Although little is known about the TeA biosynthetic pathway and its regulation mechanisms, it has been previously shown that environmental parameters, such as a w and temperature, influence its accumulation. 25,37,40 This suggests that other stress-related pathways might be connected with its production.…”

Section: Discussionmentioning

confidence: 99%

Understanding the effect of postharvest tomato temperatures on two toxigenic Alternaria spp. strains: growth, mycotoxins and cell‐wall integrity‐related gene expression

et al. 2019

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BACKGROUND Tomato fruit is susceptible to Alternaria spp. spoilage. Correct postharvest management is necessary to prevent mold growth and mycotoxin accumulation, temperature being one of the main factors associated with these problems. The effect of different postharvest temperatures (5, 12, 25, and 35 °C) on growth, mycotoxin production, and stress‐related gene expression by two Alternaria spp. was assessed. RESULTS Growth rates decreased rapidly when temperature was higher than the optimum (25 °C), while a gradual reduction was detected at lower temperatures. Tenuazonic acid (TeA) was strongly synthesized at all the temperatures that were evaluated, with a maximum between 12 and 25 °C. Alternariol monomethyl ether (AME) was produced only at the two lowest temperatures, with a peak at 12 °C. Regarding the expression of the stress‐related RHO1 gene, during active fungal growth both Alternaria spp. showed more copies of the gene as temperature increased. At the stationary phase, RHO1 gene expression was significantly higher at 12 °C, coinciding with the highest accumulation of AME. CONCLUSION Changes in temperature related to different postharvest stages of tomato fruits markedly affect toxigenic Alternaria spp. The highest levels of both mycotoxins were recorded at 12 °C, a common storage temperature for tomato fruit. An association between alternariol biosynthesis and the cell wall integrity pathway was also noticed in relation to temperature, suggesting that temperature may act as a stressor stimulating the RHO1 gene expression, which in turn triggers this mycotoxin synthesis. These results will be useful in developing new strategies to control Alternaria spoilage efficiently in tomato fruit and by‐products. © 2019 Society of Chemical Industry

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Effect of water activity and temperature on mycotoxin production by Alternaria alternata in culture and on wheat grain

Cited by 105 publications

References 28 publications

EFFECTS OF DIFFERENT STORAGE CONDITIONS ON AFLATOXIN FORMATION IN KÖME INOCULATED WITH ASPERGILLUS PARASITICUS NRRL 2999

EFFECTS OF DIFFERENT STORAGE CONDITIONS ON AFLATOXIN FORMATION IN KÖME INOCULATED WITH ASPERGILLUS PARASITICUS NRRL 2999

Effect of environmental factors on tenuazonic acid production by Alternaria alternata on soybean-based media

Understanding the effect of postharvest tomato temperatures on two toxigenic Alternaria spp. strains: growth, mycotoxins and cell‐wall integrity‐related gene expression

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