scholarly journals Modelling the effect of temperature and water activity on the growth rate of Aspergillus flavus and aflatoxin production in peanut meal extract agar

2020 ◽  
Vol 335 ◽  
pp. 108836
Author(s):  
Mahror Norlia ◽  
Selamat Jinap ◽  
Mahmud Ab. Rashid Nor-Khaizura ◽  
Son Radu ◽  
Joshua Mark John ◽  
...  
Keyword(s):  
Growth Rate ◽  
Water Activity ◽  
Aspergillus Flavus ◽  
Peanut Meal ◽  
Aflatoxin Production ◽  
Effect Of Temperature ◽  
Extract Agar

Influence of Temperature and Water Activity on Aflatoxin Production by Aspergillus flavus in Cowpea (Vigna unguiculata) Seeds and Meal

1985 ◽  
Vol 48 (12) ◽  
pp. 1040-1043 ◽  
Author(s):  
P. E. KOEHLER ◽  
L. R. BEUCHAT ◽  
M. S. CHHINNAN
Keyword(s):  
Heat Treatment ◽  
Water Activity ◽  
Aspergillus Flavus ◽  
Vigna Unguiculata ◽  
Dry Weight ◽  
Aflatoxin Production ◽  
Weight Basis ◽  
Influence Of Temperature

Experiments were done to determine the influence of temperature (21, 30 and 37°C) and aw (0.76 to 0.98) on aflatoxin production by Aspergillus flavus on cowpea (Vigna unguiculata) seeds, meal and meal supplemented with onion. Larger quantities of aflatoxin were produced at 21 and 30°C than at 37°C. The highest amount of aflatoxin (2777 μg/20 g, dry weight basis) was observed in meal containing onion at aw 0.98 after 20 d of incubation at 21°C. A level of 870 |μg/20 g was detected in seeds at aw 0.95 after 14 d of incubation at 30°C. Meal at aw 0.96 supported production of 551 μg of aflatoxin per 20 g after 20 d at 30° C. Temperature had little influence on the optimal aw for aflatoxin production in cowpea meal. However, an increase in temperature resulted in a decreased optimal aw for aflatoxin production on whole cowpeas. When known quantities of aflatoxin were added to cowpea meal which was subsequently steamed for 5 min, only 29% was extractable using a variety of procedures, indicating that the toxin may be bound in some manner to cowpea constituents as a result of heat treatment.

scholarly journals The effect of temperature and water activity on the growth of Staphylococcus aureus

2010 ◽  
Vol 27 (Special Issue 2) ◽  
pp. 28-35 ◽  
Author(s):  
A. Medveďová ◽  
Ľ. Valík ◽  
A. Studeničová
Keyword(s):  
Staphylococcus Aureus ◽  
Growth Rate ◽  
Sodium Chloride ◽  
Water Activity ◽  
Specific Growth ◽  
Incubation Temperature ◽  
Growth Parameters ◽  
Effect Of Temperature ◽  
Extended Model ◽  
Growth Responses

The growth responses of Staphylococcus aureus 2064 as affected by water activity and incubation temperature were studied in two different laboratory media. Growth parameters at temperatures from 7 to 51&deg;C and a<sub>w</sub> in the range from 1.0 to 0.86 were fitted using Ratkowsky models. The effect of temperature within its whole range on the specific growth rate was modelled by the extended model under the following equation: &radic;&micro; = 0.0456 (T &ndash; T<sub>min</sub>) [1 &ndash; e<sup>0.447(T &ndash; T<sub>max</sub>)</sup>]. The water activity values of tested media were adjusted by sodium chloride in the range from a<sub>w</sub> = 1.0 to 0.86 and experiments were conducted at 15 and 18&deg;C. The growth responses of S. aureus on water activity at 15&deg;C and 18&deg;C in PCA broth and BHI broth was described by simplified Ratkowsky model in the form: &radic;&micro; = b &times; a<sub>w</sub>. Validation of the found relationships confirmed sound fitting of the data and thus the referred results of the isolate originated from ewes&rsquo; cheese can be used in the growth prediction of S. aureus, reliably.

Effect of Temperature, Water Activity and Other Toxigenic Mold Species on Growth of Aspergillus flavus and Aflatoxin Production on Corn, Pinto Beans and Soybeans

1988 ◽  
Vol 51 (5) ◽  
pp. 361-363 ◽  
Author(s):  
MARY W. TRUCKSESS ◽  
LEONARD STOLOFF ◽  
PHILIP B. MISLIVEC
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Penicillium Citrinum ◽  
Effect Of Temperature ◽  
Mold Growth ◽  
Additional Water ◽  
Pinto Beans ◽  
Native Strains ◽  
Temperature Water

Portions of corn, a commodity in which aflatoxin is frequently found, were held at 16, 26 and 32°C after the moisture contents were adjusted to achieve water activities (aw) ranging from too low to ample for support of mold growth. Suspensions of mold spores from toxigenic cultures of Aspergillus flavus, A. ochraceus, Penicillium citrinum, P. cyclopium and P. urticae were added to the test portions, either as A. flavus alone, as A. flavus with one of the other molds or as a mixture of all 5 species. Additional water was used to obtain the proper moisture levels. A temperature of 16°C was generally too low for aflatoxin production by either the added or native strains of A. flavus, although the mold was able to grow at 16°C at aw values as low as 0.80, 0.77 and 0.85 on corn, soybeans and pinto beans, respectively. Aflatoxin production was essentially the same at 26 and 32° C with limiting aw values in the range of 0.85–0.89. Limiting aw values for mold growth at 26 and 32°C were 0.73, 0.69 and 0.75 for corn, soybeans and pinto beans, respectively. This study provided no evidence that substrate suitability at limiting temperatures and aw levels is a factor in the observed difference in the risk of aflatoxin contamination for these commodities. The study did indicate that the associated mold flora, when the seed is exposed to mold invasion, is a risk determinant.

scholarly journals Temperature, water activity and gas composition effects on the growth and aflatoxin production by Aspergillus flavus on paddy

2016 ◽  
Vol 67 ◽  
pp. 49-55 ◽  
Author(s):  
Wael Mousa ◽  
Farinazleen Mohd. Ghazali ◽  
S. Jinap ◽  
Hasanah Mohd. Ghazali ◽  
Son Radu ◽  
...  
Keyword(s):  
Water Activity ◽  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Gas Composition ◽  
Composition Effects ◽  
Temperature Water

scholarly journals Growth response of Aspergillus flavus IMS1103 isolated from poultry feed

2016 ◽  
Vol 2 (2) ◽  
pp. 221-228 ◽  
Author(s):  
Monzur Morshed Ahmed ◽  
Md Fakruddin ◽  
Md Nur Hossain ◽  
Khandaker Rayhan Mahbub ◽  
Abhijit Chowdhury
Keyword(s):  
Growth Rate ◽  
Aspergillus Flavus ◽  
Growth Response ◽  
Culture Media ◽  
Agar Medium ◽  
Lag Time ◽  
Potato Dextrose Agar ◽  
Poultry Feed ◽  
Effect Of Temperature ◽  
Temperature Range

Aspergillus flavus strains were isolated from locally available poultry feeds. Effect of temperature, pH and culture media on growth of Aspergillus flavus was studied. Temperature ranged from 4-42°C (4, 10, 20, 25, 30, 37 and 42°C) was examined. Except for 4°C and 10°C, the isolate was able to grow for the whole temperature range. The growth was maximum at 25°C and was influenced with increasing or decreasing of temperature from 42°C to 20°C.The lag time was strongly influenced by the temperature at lower temperature level than at higher temperature range. Effect of pH on growth of Aspergillus flavus was also examined; from comparison of 3 different pH levels, it is concluded that at most temperatures pH 6.5 showed a higher growth rate and as a consequence required a shorter time to achieve maximum colony diameter. No significant variations in the lag time were observed. A natural poultry feed meal agar medium (FMAM) was developed in the laboratory and growth of A. flavus was compared with other 2 synthetic dehydrated media namely; Czapek’sdox Agar (CDA) and potato dextrose Agar (PDA). Poultry feed meal agar medium showed better growth response than Czapek’sdox agar and potato dextrose agar at all conditions. At 25°C and pH 6.5 found optimum for growth of Aspergillus flavus in feed meal agar medium whereas, temperature 30°C and pH 6.5 found optimum for growth for Czapek’sdox agar media and temperature 30°C and pH 6 showed high growth rate on potato dextrose agar. Poultry feed meal media showed high affinity for growth of mycelium and early spore formation than other media examined.Asian J. Med. Biol. Res. June 2016, 2(2): 221-228

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