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

1979 ◽  
Vol 42 (6) ◽  
pp. 485-490 ◽  
Author(s):  
M. D. NORTHOLT ◽  
H. P. VAN EGMOND ◽  
W. E. PAULSCH
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Minimum Temperature ◽  
Fungal Species ◽  
Aspergillus Ochraceus ◽  
Optimum Temperature ◽  
Temperature Range ◽  
Penicillium Cyclopium ◽  
Agar Media ◽  
Penicillium Viridicatum

The effects of water activity (aw) and temperature on growth of and ochratoxin A (OA) production by strains of Aspergillus ochraceus, Penicillium cyclopium, and Penicillium viridicatum were investigated. On agar media in which the aw had been adjusted by addition of sucrose or glycerol, the minimum aw values for OA production by A. ochraceus, P. cyclopium and P. viridicatum lay between 0.83–0.87, 0.87–0.90, and 0.83–0.86, respectively. At 24 C, optimum aw values for OA production by A. ochraceus and P. cyclopium were 0.99 and 0.95–0.99, respectively, whereas that of P. viridicatum varied and was 0.95 and 0.99 for the two strains tested. At optimum aw, the temperature range for OA production by A. ochraceus was 12–37 C, whereas that of P. cyclopium and P. viridicatum was 4–31 C. Optimum temperature for OA production by A. ochraceus was 31 C, whereas that of P. cyclopium and P. viridicatum was 24 C. On Edam cheese of 0.95 aw the minimum temperature for OA production by P. cyclopium was 20 C. On barley meal, P. viridicatum produced maximal quantities of OA at 0.97 aw and could produce OA at temperatures as low as 12 C.

Penicillic Acid Production by Some Fungal Species in Relation to Water Activity and Temperature

1979 ◽  
Vol 42 (6) ◽  
pp. 476-484 ◽  
Author(s):  
M. D. NORTHOLT ◽  
H. P. VAN EGMOND ◽  
W. E. PAULSCH
Keyword(s):  
Water Activity ◽  
Culture Media ◽  
Fungal Species ◽  
Aspergillus Ochraceus ◽  
Poultry Feed ◽  
Optimum Temperature ◽  
Penicillic Acid ◽  
Different Temperatures ◽  
Temperature Ranges ◽  
Gouda Cheese

The combined effects of water activity (aw) and temperature on growth of and penicillic acid (PA) production by strains of Penicillium cyclopium, Penicillium martensii, and Aspergillus ochraceus were determined. On malt agar media in which the aw had been adjusted by addition of sucrose or glycerol, the minimum aw for PA production by P. cyclopium and A. ochraceus was 0.97 and that of P. martensii was 0.99. The temperature range for PA production by P. cyclopium and P. martensii was 4–31 C, whereas that of A. ochraceus was 8–31 C. Optimum temperature for PA production by P. cyclopium and A. ochraceus varied with the strain tested and was 24–31 C. The only strain of P. martensii tested showed an optimum temperature of 16–24 C. On Gouda and Tilsiter cheese of 0.96–0.98 aw, temperature ranges for growth of P. cyclopium, a common mold on cheese, were 0–24 and 4–16 C, respectively. When a strain of P. cyclopium known to be able to produce PA in culture media, was grown on Gouda cheese incubated at different temperatures, no PA was detectable in the moldy cheese at the time the average colony diameter was 30 mm. However, in a culture on Gouda cheese incubated for a prolonged time (42 days) at 16 C, PA was detectable. On poultry feed, A. ochraceus produced PA aw as low as 0.88, whereas the minimum aw for PA production by P. cyclopium was 0.97.

scholarly journals Influence of physiological factors on growth, sporulation and ochratoxin A/B production of the new Aspergillus ochraceus grouping

2009 ◽  
Vol 2 (4) ◽  
pp. 429-434 ◽  
Author(s):  
A. Abdel-Hadi ◽  
N. Magan
Keyword(s):  
Ochratoxin A ◽  
Maximum Growth ◽  
Spore Production ◽  
Aspergillus Ochraceus ◽  
Optimum Temperature ◽  
Physiological Factors ◽  
Large Numbers ◽  
Asexual Spore ◽  
The Impact ◽  
First Time

Recently, new species within the Aspergillus section Circumdati group responsible for ochratoxin production were reported. This study has examined the impact of interactions between water activity (aw, 0.99-0.90), temperature (20-35 °C) on growth, asexual spore production and ochratoxin A and B (OTA and OTB) on strains of each of the three species from this new grouping (A. ochraceus, A. steynii, and A. westerdijkiae) for the first time. The maximum growth occurred at 0.95 aw and 30 °C for both A. ochraceus and A. westerdijkiae, while it was at 0.99 aw and 30 °C for A. steynii. No conidial spore production occurred at 0.99 aw in cultures of A. ochraceus and A. steynii but large numbers of spores (2.3×107/cm2) were produced by A. westerdijkiae. Optimum temperature for spore production was 0.95 aw and 30 °C for A. westerdijkiae and A. ochraceus, and 0.95 aw and 35 °C for A. steynii. Quantification of OTA showed that optimum was produced at 0.99 aw, by A. steynii at 30 °C, for A. westerdijkiae at 25 °C and for A. ochraceus at 20 °C. As water stress was imposed (0.95 aw), the temperature for maximum OTA production changed. For example, for A. steynii and A. westerdijkiae this was at 35 °C, for A. ochraceus, 25 °C. Much less OTB was produced relative to OTA, but the production followed the same pattern at all aw levels and temperatures. This is the first detailed study to examine the similarities and differences in ecology of these related species in this important mycotoxigenic group.

scholarly journals The role of paecilomyces lilacinus (thom) samson and other fungal species in biodegradation of ochratoxin a

2011 ◽  
pp. 103-110
Author(s):  
Aleksandra Bocarov-Stancic ◽  
Jelena Levic ◽  
Natasa Salma ◽  
Slavica Stankovic ◽  
Vladimir Pantic ◽  
...  
Keyword(s):  
Ochratoxin A ◽  
Solid Substrate ◽  
Fungal Species ◽  
Paecilomyces Lilacinus ◽  
Aspergillus Ochraceus ◽  
Test Medium ◽  
Constant Weight ◽  
Rice Grains ◽  
Cultivation Substrate

Nine isolates of fungi of genera Aspergillus, Fusarium, Paecilomyces and Penicillium were cultured on the modified Vogel?s medium with the addition of crude ochratoxin A (OTA) extract. This crude OTA extract was derived from a natural solid substrate on which Aspergillus ochraceus strain CBS 108.08 was cultivated. OTA was isolated, partially purified, dried by evaporating and dissolved in ethanol (1 mg ml-1), and added to the test medium up to the final concentration of 10 ?g ml-1. The presence of OTA residues was determined after 7 and 14 day cultivation of fungi in the test medium at 27?1?C. The Paecilomyces lilacinus isolate (Inf. 2/A), which completely degraded OTA (150 ?g) after only seven days, was selected for further studies. Wet sterile rice grains (50 g + 25 ml distilled water) were inoculated with individual isolates of fungi A. ochraceus (strain CBS 108.08) and P. lilacinus (isolate Inf. 2/A), and with their combination. In the case of P. lilacinus monoculture, 0.9 mg of crude OTA was also added into cultivation substrate. Each test was done in three replications. After the four week cultivation of individual and combined fungi at 27?1?C, inoculated rice grains were dried to the constant weight and pulverized. OTA was determined in these samples by the application of standard TLC method for fodder analysis. OTA in the amount of 61.310 ?g kg-1 dry matter (DM) was determined only in the samples inoculated with a producer of ochratoxin A (A. ochraceus, strain CBS 108.08). On the other hand, a much smaller amount of OTA (80 ?g kg-1 DM) was detected in samples inoculated with combined cultures of A. ochraceus and P. lilacinus isolates. Gained results indicate that P. lilacinus degraded, on average, 99.8% of OTA. After four week cultivation, the same fungal isolate in the samples of wet sterile rice kernels with the addition of 0.9 mg of crude OTA, completely degraded added crude OTA (<8 ?g kg-1).

Effect of Water Activity, Temperature, and Mixed Fungal Spore Interactions on Ochratoxin A Production by Aspergillus carbonarius

2015 ◽  
Vol 78 (2) ◽  
pp. 376-382 ◽  
Author(s):  
EFSTATHIA A. KOGKAKI ◽  
PANTELIS I. NATSKOULIS ◽  
GEORGE-JOHN E. NYCHAS ◽  
EFSTATHIOS Z. PANAGOU
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Incubation Time ◽  
Interspecific Interactions ◽  
Grape Juice ◽  
Fungal Spore ◽  
Fungal Species ◽  
Aspergillus Carbonarius ◽  
Different Temperatures

The purpose of this work was to investigate the potential of two nontoxigenic Aspergillus section Nigri species (Aspergillus tubingensis and Aspergillus japonicus) to influence the in vitro ochratoxin A (OTA) production of three toxigenic Aspergillus carbonarius isolates (Ac-28, Ac-29, and Ac-33) from Greek vineyards of different geographical areas. OTA accumulation was evaluated by inoculation of 0:100, 25:75, 50:50, 75:25, and 100:0 ratios of mixed spore suspensions on a synthetic grape juice medium for up to 28 days at different temperatures (15, 20, and 25°C), water activity (aw) levels (0.95 and 0.98 aw) and incubation time (7, 14, 21, and 28 days). Results confirmed that environmental factors and fungal species had a significant effect on OTA production. Specifically, maximum OTA concentration for Ac-28 (3.21 μg g−1) and Ac-29 (7.69 μg g−1) was observed at 20°C/0.98 aw and for Ac-33 (9.13 μg g−1) at 15°C/0.95 aw, regardless of incubation time. Moreover, A. tubingensis had no significant influence on OTA concentration of all toxigenic isolates assayed, regardless of temperature, aw, and incubation time. On the other hand, the presence of A. japonicus slightly inhibited OTA production of Ac-29 and Ac-33, while for Ac-28, stimulation of OTA was observed in some cases. Overall, lower aw levels reduced OTA accumulation for Ac-28 and Ac-29, regardless of temperature, inoculum ratio, and time. On the contrary, for Ac-33, low aw increased OTA production, regardless of the investigated parameters. The importance of this study concerns the understanding of interspecific interactions on OTA diffusion by A. carbonarius in an attempt to find ways to prevent the presence of toxins in grapes and their derivatives.

Effect of Water Activity and Temperature on Mycelial Growth and Ochratoxin A Production by Isolates of Aspergillus ochraceus on Irradiated Green Coffee Beans

2005 ◽  
Vol 68 (1) ◽  
pp. 133-138 ◽  
Author(s):  
E. PARDO ◽  
S. MARÍN ◽  
A. J. RAMOS ◽  
V. SANCHIS
Keyword(s):  
Ochratoxin A ◽  
Water Activity ◽  
Mycelial Growth ◽  
Marked Decrease ◽  
Limit Of Detection ◽  
Aspergillus Ochraceus ◽  
Primary Data ◽  
Green Coffee ◽  
Green Coffee Beans ◽  
Coffee Beans

Aspergillus ochraceus as a fungal contaminant and ochratoxin A (OTA) producer plays an important role in coffee quality. Temperature and water activity (aw) significantly influence mycelial growth and OTA production by isolates of A. ochraceus on green coffee beans. Maximum mycelial growth was found at 30°C and 0.95 to 0.99 aw. A marked decrease in growth rate was observed when temperature and aw were reduced. At 0.80 aw, mycelial growth occurred only at 30 and 20°C for one isolate. Maximum OTA production was found at 20°C and 0.99 aw. At 10°C, OTA was not produced, regardless of aw. Similarly, no OTA was detected at 0.80 aw. OTA production ranged from the limit of detection (40 ng g−1 of green coffee) to 17,000 ng g−1 of green coffee. Significant intraspecific differences in mycelial growth and OTA production were found. Primary data for lag phases prior to mycelial growth under the influence of temperature and aw were modelled by multiple linear regression, and the response surface plots were obtained.

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

1978 ◽  
Vol 41 (11) ◽  
pp. 885-890 ◽  
Author(s):  
M. D. NORTHOLT ◽  
H. P. VAN EGMOND ◽  
W. E. PAULSCH
Keyword(s):  
Water Activity ◽  
Fungal Species ◽  
Malt Agar ◽  
Penicillium Expansum ◽  
Combined Effects ◽  
Aspergillus Clavatus ◽  
Growth Optimum ◽  
Golden Delicious ◽  
Temperature Ranges ◽  
Agar Media

The combined effects of water activity (aw) and temperature on growth and patulin production by strains of Penicillium expansum, Penicillium patulum, and Aspergillus clavatus were determined. Malt agar media were used, in which the aw was adjusted by addition of sucrose or glycerine. The minimum aw values for patulin production by P. expansum, P. patulum, and A. clavatus were 0.99, 0.95, 0.99, respectively. The temperature ranges for patulin production by P. expansum, P. patulum, and A. clavatus were 0–24, 4–31, and 12–24 C, respectively. The optimum temperatures for patulin production by P. expansum and A. clavatus were low compared with those for growth. Optimum temperatures for patulin production at high aw by P. patulum varied with the strain tested and were 8 or 31 C. The temperature range for patulin production in apples by P. expansum was determined. The minimum temperatures for rotting and patulin production were 1 C in Cox Orange cv. and 4 C in Golden Delicious cv. The amount of patulin accumulating in rotten tissue of six apple varieties differed greatly. The invasiveness of and patulin production by various strains of four patulin-producing fungal species were tested. All P. expansum strains tested caused rot containing patulin. The increase of rot and patulin production by P. crustosum and A. clavatus depended on the strains tested. None of the P. patulum strains was able to invade Golden Delicious apples.

Sensitivity to Natamycin1 (Pimaricin) of Fungi Isolated in Cheese Warehouses

1977 ◽  
Vol 40 (8) ◽  
pp. 533-536 ◽  
Author(s):  
E. de BOER ◽  
M. STOLK-HORSTHUIS
Keyword(s):  
Ochratoxin A ◽  
Aspergillus Versicolor ◽  
Penicillic Acid ◽  
Experimental Conditions ◽  
Laboratory Conditions ◽  
Penicillium Cyclopium ◽  
Continuous Use ◽  
Natamycin Production ◽  
Penicillium Viridicatum

The sensitivity to natamycin of molds and yeasts isolated in cheese warehouses where natamycin has been used for various periods was determined. After several years of continuous use of natamycin no natamycin-insensitive molds and yeasts were found. In 26 strains of molds isolated in cheese warehouses it was not possible under laboratory conditions to decrease the sensitivity for natamycin. Besides the sensitivity of fungi to natamycin, production of mycotoxins by the isolated molds was investigated. Strains of Penicillium viridicatum, Aspergillus versicolor, and Penicillium cyclopium isolated in the warehouses produced, under experimental conditions, ochratoxin A, sterigmatocystin, and penicillic acid, respectively.

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