scholarly journals Growth and toxin production of phomopsin A and ochratoxin A forming fungi under different storage conditions in a pea (Pisum sativum) model system

2021 ◽  
Author(s):  
Birgitta Maria Kunz ◽  
Laura Pförtner ◽  
Stefan Weigel ◽  
Sascha Rohn ◽  
Anselm Lehmacher ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Fungal Growth ◽  
Toxin Production ◽  
Storage Conditions ◽  
Grain Legumes ◽  
Model System ◽  
Relative Air Humidity ◽  
Phomopsis Leptostromiformis ◽  
Elevated Water

AbstractPhomopsins are mycotoxins mainly infesting lupines, with phomopsin A (PHOA) being the main mycotoxin. PHOA is produced by Diaporthe toxica, formerly assigned as toxigenic Phomopsis leptostromiformis, causing infections in lupine plants and harvested seeds. However, Diaporthe species may also grow on other grain legumes, similar to Aspergillus westerdijkiae as an especially potent ochratoxin A (OTA) producer. Formation of PHOA and OTA was investigated on whole field peas as model system to assess fungal growth and toxin production at adverse storage conditions. Field pea samples were inoculated with the two fungal strains at two water activity (aw) values of 0.94 and 0.98 and three different levels of 30, 50, and 80% relative air humidity.After 14 days at an aw value of 0.98, the fungi produced 4.49 to 34.3 mg/kg PHOA and 1.44 to 3.35 g/kg OTA, respectively. Strains of D. toxica also tested showed higher PHOA concentrations of 28.3 to 32.4 mg/kg.D. toxica strains did not grow or produce PHOA at an aw values of 0.94, while A. westerdijkiae still showed growth and OTA production.Elevated water activity has a major impact both on OTA and, even more pronouncedly, on PHOA formation and thus, proper drying and storage of lupins as well as other grain legumes is crucial for product safety.

Water Activity and Temperature Effects on Fungal Growth and Ochratoxin A Production by Ochratoxigenic Aspergillus carbonarius Isolated from Tunisian Grapes

2010 ◽  
Vol 75 (2) ◽  
pp. M89-M97 ◽  
Author(s):  
Salma Lasram ◽  
Souheib Oueslati ◽  
Ana Valero ◽  
Sonia Marin ◽  
Abdelwahed Ghorbel ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Temperature Effects ◽  
Fungal Growth ◽  
Aspergillus Carbonarius

Incidence of Penicillium verrucosum in Grain Samples from Oat Varieties Commonly Grown in South Dakota

2018 ◽  
Vol 81 (6) ◽  
pp. 898-902 ◽  
Author(s):  
BANDANA DHUNGANA ◽  
SHAUKAT ALI ◽  
EMMANUEL BYAMUKAMA ◽  
PADMANABAN KRISHNAN ◽  
MELANIE CAFFE-TREML
Keyword(s):  
South Dakota ◽  
Fungal Growth ◽  
Toxin Production ◽  
The United States ◽  
Storage Conditions ◽  
Fungal Species ◽  
The European Union ◽  
Penicillium Verrucosum ◽  
Cereal Grain ◽  
Two Samples

ABSTRACT Ochratoxin A (OTA) can cause toxicogenic effects in humans and animals when contaminated food products are consumed. Oat (Avena sativa), like any other cereal grain, can be contaminated with OTA when storage conditions are favorable for fungal growth and toxin production. South Dakota is among the leading oat-producing states in the United States. It is therefore important to determine the frequency of occurrence of the primary OTA-producing fungal species on oat grains produced in the state. In this study, we evaluated oat grain samples from South Dakota for the incidence of Penicillium verrucosum, the major ochratoxigenic fungus in temperate regions. Kernels from 12 oat cultivars grown at multiple locations in South Dakota from 2014 to 2016 (15 location-year combinations) were plated on dichloran yeast extract sucrose glycerol agar medium. P. verrucosum was detected on 0.30, 0.19, and 0.05% of the kernels tested in 2014, 2015, and 2016, respectively. Overall, 22 of the 360 evaluated samples had kernels contaminated with P. verrucosum. The fungal incidence of the contaminated samples ranged from 1 to 16%, and the majority of those samples originated from one location. All samples from 2014 and 2015 (n = 240), except two, had no detectable levels of OTA. The concentration of OTA was well under the maximum limit recommended by the European Union for the two samples with detectable levels of OTA.

Mycotoxins and toxigenic fungi on cereal grains in western Canada

1990 ◽  
Vol 68 (7) ◽  
pp. 982-986 ◽  
Author(s):  
John T. Mills
Keyword(s):  
Ochratoxin A ◽  
Fusarium Species ◽  
Ergot Alkaloids ◽  
Toxin Production ◽  
Storage Conditions ◽  
Cereal Grains ◽  
Western Canada ◽  
Aspergillus Versicolor ◽  
Toxigenic Fungi ◽  
Penicillium Aurantiogriseum

Toxins occasionally present on cereal grains in the field in western Canada include ergot alkaloids produced by Claviceps purpurea and trichothecenes produced by Fusarium species, particularly Fusarium sporotrichioides and Fusarium graminearum. HT-2 toxin, T-2 toxin, diacetoxyscirpenol, and deoxynivalenol are the main trichothecenes encountered. During storage of cereals, the predominant toxins and toxigenic fungi are ochratoxin A and citrinin produced by Penicillium aurantiogriseum, P. chrysogenum, and P. verrucosum and sterigmatocystin produced by Aspergillus versicolor. The incidence of toxin-contaminated grains is extremely low relative to the volume of grains produced. Occurrence of toxins is influenced by field moisture, temperature, and bin storage conditions of a particular year. The risk of toxin production is highest in durum wheat and lowest in oats.Key words: ochratoxin A, citrinin, deoxynivalenol, T-2 toxin, ergot alkaloids.

Influence of water activity on physical properties, fungal growth, and Ochratoxin A production in dry cherries and green‐coffee beans

2021 ◽  
Author(s):  
Erick Baruch Estrada‐Bahena ◽  
Ricardo Salazar ◽  
Mónica Ramírez ◽  
Ma. Elena Moreno‐Godínez ◽  
Javier Jiménez‐Hernández ◽  
...  
Keyword(s):  
Physical Properties ◽  
Ochratoxin A ◽  
Water Activity ◽  
Fungal Growth ◽  
Green Coffee ◽  
Green Coffee Beans ◽  
Coffee Beans ◽  
Influence Of Water

Impact of Water Activity and Temperature on Growth and Ochratoxin A Production of Two Aspergillus carbonarius Isolates from Wine Grapes in Greece

2007 ◽  
Vol 70 (12) ◽  
pp. 2884-2888 ◽  
Author(s):  
CHRYSOULA C. TASSOU ◽  
PANTELIS I. NATSKOULIS ◽  
EFSTATHIOS Z. PANAGOU ◽  
APOSTOLOS E. SPIROPOULOS ◽  
NARESH MAGAN
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Color Change ◽  
Fungal Growth ◽  
Grape Juice ◽  
Lag Phase ◽  
Aspergillus Carbonarius ◽  
Wine Grapes ◽  
Wine Production

The aim of this study was to determine the effects of water activity (aw; 0.85 to 0.98) and temperature (10 to 40°C) on the radial growth rate and ochratoxin A (OA) production of two Aspergillus carbonarius isolates in vitro. The isolates were obtained from wine grapes cultivated in Greece, and the trial was conducted with a synthetic grape juice medium similar in composition to grapes between veraison (beginning of color change) and ripeness. Fungal growth and OA production data were collected for 55 days. Response surface curves and cardinal values for aw and temperature were obtained using multiple regression analysis. The lag phase lasted from less than 1 to 10 days. Both isolates grew optimally at 30 to 35°C and 0.96 aw, but maximum OA production occurred under suboptimal growth conditions (15 to 20°C and 0.93 to 0.96 aw). Growth also was observed at 0.85 aw and 25°C, however at this same aw the fungus failed to produce mycelium at any other temperatures tested. The isolates produced OA at 15 to 30°C and 0.90 to 0.98 aw. Maximum OA production was detected after 25 days of incubation at 20°C and 0.96 aw and was 3.14 and 2.67 μgg−1, respectively, for the two strains. The isolated strains used in this study were more xerotolerant than others from the Mediterranean basin. These data will allow producers to identify and thus monitor critical environmental conditions effectively in wine grapes. These data also increase the knowledge base concerning the ability of A. carbonarius to grow and produce toxin under different ecological conditions and can contribute to the development of secondary models for the prediction and risk assessment of OA in wine production.

Effect of Temperature, Water Activity, and pH on Growth and Production of Ochratoxin A by Aspergillus niger and Aspergillus carbonarius from Brazilian Grapes

2014 ◽  
Vol 77 (11) ◽  
pp. 1947-1952 ◽  
Author(s):  
FABIANA REINIS FRANCA PASSAMANI ◽  
THAIS HERNANDES ◽  
NOELLY ALVES LOPES ◽  
SABRINA CARVALHO BASTOS ◽  
WILDER DOUGLAS SANTIAGO ◽  
...  
Keyword(s):  
Aspergillus Niger ◽  
Ochratoxin A ◽  
Water Activity ◽  
Fungal Growth ◽  
Grape Juice ◽  
Effect Of Temperature ◽  
Aspergillus Carbonarius ◽  
Optimal Conditions ◽  
Wide Range ◽  
Temperature Water

The growth of ochratoxigenic fungus and the presence of ochratoxin A (OTA) in grapes and their derivatives can be caused by a wide range of physical, chemical, and biological factors. The determination of interactions between these factors and fungal species from different climatic regions is important in designing models for minimizing the risk of OTA in wine and grape juice. This study evaluated the influence of temperature, water activity (aw), and pH on the development and production of OTA in a semisynthetic grape culture medium by Aspergillus carbonarius and Aspergillus niger strains. To analyze the growth conditions and production of OTA, an experimental design was conducted using response surface methodology as a tool to assess the effects of these abiotic variables on fungal behavior. A. carbonarius showed the highest growth at temperatures from 20 to 33°C, aw between 0.95 and 0.98, and pH levels between 5 and 6.5. Similarly, for A. niger, temperatures between 24 and 37°C, aw greater than 0.95, and pH levels between 4 and 6.5 were optimal. The greatest toxin concentrations for A. carbonarius and A. niger (10 μg/g and 7.0 μg/g, respectively) were found at 15°C, aw 0.99, and pH 5.35. The lowest pH was found to contribute to greater OTA production. These results show that the evaluated fungi are able to grow and produce OTA in a wide range of temperature, aw, and pH. However, the optimal conditions for toxin production are generally different from those optimal for fungal growth. The knowledge of optimal conditions for fungal growth and production of OTA, and of the stages of cultivation in which these conditions are optimal, allows a more precise assessment of the potential risk to health from consumption of products derived from grapes.

Effect of water activity, temperature, and incubation period on fungal growth and ochratoxin A production on Nyjer seeds

2018 ◽  
Vol 35 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Dawit Gizachew ◽  
Yung-Chen Hsu ◽  
Barbara Szonyi ◽  
Wei-tsyi Evert Ting
Keyword(s):  
Ochratoxin A ◽  
Incubation Period ◽  
Water Activity ◽  
Fungal Growth ◽  
Effect Of Water ◽  
Activity Temperature

Effect of Salt Level and Nitrite on Toxin Production by Clostridium botulinum Type E Spores in Smoked Great Lakes Whitefish1

1987 ◽  
Vol 50 (3) ◽  
pp. 212-217 ◽  
Author(s):  
S. L. CUPPETT ◽  
J. I. GRAY ◽  
J. J. PESTKA ◽  
A. M. BOOREN ◽  
J. F. PRICE ◽  
...  
Keyword(s):  
Great Lakes ◽  
Water Activity ◽  
Salt Concentration ◽  
Clostridium Botulinum ◽  
Toxin Production ◽  
Water Phase ◽  
Salt Level ◽  
Botulinum Type ◽  
Clostridium Botulinum Type E ◽  
Average Water

The effect of salt level and nitrite on botulinal safety of smoked whitefish was investigated. An average water-phase (wp) salt concentration of 4.4% inhibited outgrowth of Clostridium botulinum type E spores (103 spores/g) for over 35 d in temperature-abused (27°C) smoked whitefish. Incorporation of nitrite (220 mg/kg) during brining to the smoked salted (4.4%, wp) whitefish inhibited toxin production for 56 d at 27°C. An average salt concentration of 6.2% (wp), with or without nitrite, totally inhibited toxin production for the duration of the study (83 d). The effect of pH and water activity in temperature-abused smoked whitefish as a means of controlling toxin production by C. botulinum type E spores was evaluated.

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