Ochratoxin A Production by Some Fungal Species in Relation to Water Activity and Temperature

Northolt, M. D.; Egmond, H. P. van; Paulsch, W. E.

doi:10.4315/0362-028x-42.6.485

Cited by 100 publications

(34 citation statements)

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“…If the soft ripe fruits have been infected with A.flauus, the conditions in the early stage of sun drying may favour aflatoxin accumulation in the orchard. Although the lower limit for aflatoxin and ochratoxin A formation is reported as 0.83, they can be produced at lower a, values depending on the substrate and incubation conditions [19,20].…”

Section: Figs Investigated During Dryingmentioning

confidence: 99%

Influence of harvesting and drying techniques on microflora and mycotoxin contamination of figs

Özay

Aran

Pala

1995

Nahrung

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Mould growth and mycotoxin (aflatoxins and ochratoxin A) formation were examined in the 1993 dried figs crop. The relationships between mould/mycotoxin contamination and orchard conditions, different harvesting techniques, harvesting time and intactness of fruits were investigated. The fruits were examined during drying and effects of different pretreatments, sun drying and solar drying on the mould and mycotoxin contamination in figs were also studied. Aflatoxins (B1, B2, G1 and G2) were not present in the firm or shrivelled ripe figs. Among the samples examined during drying, only one of the 32 samples was found to be aflatoxin positive. Ochratoxin A was not detected in any of the samples analysed. The moisture content, aw and pH values of full ripe and shrivelled fruits were suitable for mould growth and mycotoxin formation while these parameters in pretreated and dried fruits were found to be too low to allow such outcome. It was observed that harvesting the fruit by hand-treating with different solutions and application of solar drying were effective in reducing contamination level.

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Section: Figs Investigated During Dryingmentioning

confidence: 99%

Influence of harvesting and drying techniques on microflora and mycotoxin contamination of figs

Özay

Aran

Pala

1995

Nahrung

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“…The highest amounts of ochratoxin A were obtained at 0.98 a w , regardless of the temperature level, with optimum ochratoxin A production occurring between 25-30 °C, depending on the isolates. Both growth and ochratoxin A accumulation increased with increasing a w levels until 0.96-0.98 a w , with 0.80 a w (at 25-30 °C) being the minimum a w required for growth on maize-based media ) and 0.83-0.87 a w the minimum for ochratoxin A production (Northolt et al 1979). The food matrix and nutritional status is very important in determining ochratoxin A production (Madhyastha et al 1990).…”

Section: Ochratoxinsmentioning

confidence: 96%

“…Ochratoxin B has been found very occasionally in some foods (Visconti and Bottalico 1983) and is less toxic than ochratoxin A. Ochratoxin A has been shown to be produced by several species in the A. ochraceus group and by A. alliaceus, A. albertensis, A. niger, A. carbonarius (Abarca et al 1994;Varga et al 1996), and P. verrucosum (Northolt et al 1979). These species contaminate different crops with different distributions depending on the climatic conditions.…”

Section: Ochratoxinsmentioning

confidence: 99%

Ecological conditions affecting mycotoxin production in cereals: a review

Milani¹

2013

Vet. Med.

146

105

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Spoilage fungi are ubiquitous contaminants of cereals, pre-and post-harvest. These fungi can produce a wide range of secondary metabolites under ecological conditions which are conducive for growth. However, some of these secondary metabolites are toxic and have a significant impact if they enter the production and animal food chains. Prevention of mycotoxin contamination of feed and food raw materials is now considered more important than subsequent cure. The key ecological determinants pre-and post-harvest are water availability and temperature (climate). Accurate information is therefore needed on the impact of an association between these key factors, and it is necessary to understand which are marginal and which critical for germination and toxin production. There have only been a few studies where attempts have been made to integrate the available information on these factors in relation to different raw materials for feed and food processing, especially cereals. This review will examine the available information on the main climatic factors, i.e., water availability and temperature affecting mycotoxin production such as, aflatoxins, ochratoxins, fumonisins, zearalenone, deoxynivalenol and citrinin. This information is crucial for accurately focusing and monitoring key critical control points in the feed and food chain to optimise prevention strategies.

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“…High yield of ochratoxin was obtained after 19 days of incubation in 60% moisture content. According to Northolt et al (1979) A. ochraceus had the ability to grow at water activity (a w ) as low as 0.79 and reported optimum a w for growth was 0.95. The minimum a w for toxin production by A. ochraceus varied from 0.83 to 0.87 with an optimum of 0.99.…”

Section: Effect Of Roasting On Ochratoxin a Level In Coffee Beansmentioning

confidence: 99%

Isolation of Aspergillus ochraceus and Production of Ochratoxin in Coffee Samples

Pandit¹,

Panta²,

Karki

2015

Nepal Journal of Science and Technology

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The occurrence of mycotoxins in foods and feeds has long been recognized as a potential hazard for human and animal health due to their severe toxic and carcinogenic properties. Among various mycotoxins, ochratoxin A (OTA) is the most hazardous one because of its serval contamination cases in the world. In this study contamination levels of Aspergillus ochraceus in coffee samples were assessed, where two strains of it were isolated from 65 coffee samples. They were confirmed by using Czapeck yeast extract agar (CYA). Fermentation was carried out for ochratoxin production at different moisture levels: 20%, 40% and 60% by using coffee as a substrate. The extract was assayed for the presence of ochratoxin by thin layer chromatography (TLC). Results showed that high production of this toxin (402 ppb) was obtained in coffee containing 60% of moisture after 19 days of incubation period with high load of fungal growth and the effect of roasting on coffee containing ochratoxin was observed where the level of it was decreased after roasting. It can be concluded that coffee substrate with high level of moisture favored good condition for the growth of A. ochraceus and ochratoxin formation.

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Ochratoxin A Production by Some Fungal Species in Relation to Water Activity and Temperature

Cited by 100 publications

References 0 publications

Influence of harvesting and drying techniques on microflora and mycotoxin contamination of figs

Influence of harvesting and drying techniques on microflora and mycotoxin contamination of figs

Ecological conditions affecting mycotoxin production in cereals: a review

Isolation of Aspergillus ochraceus and Production of Ochratoxin in Coffee Samples

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