Growth and Synthesis of Aflatoxin by Aspergillus parasiticus in the Presence of Sorbic Acid

1981 ◽  
Vol 44 (10) ◽  
pp. 736-741 ◽  
Author(s):  
AHMED E. YOUSEF ◽  
ELMER H. MARTH
Keyword(s):  
Incubation Period ◽  
Aspergillus Parasiticus ◽  
Sorbic Acid ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Mold Growth ◽  
Early Stages ◽  
Cumulative Data ◽  
The Media ◽  
Growth Ph

Two media [basal (M1) and enriched (M2)] containing potassium sorbate (0–300 ppm as sorbic acid) were inoculated with spores (104 – 106/flask) of Aspergillus parasiticus and incubated for 5 days at 28 C. The greater the amount of sorbate added, the higher was the pH of the media after incubation and the smaller was the yield of mold mycelium. Intermediate amounts of sorbate sometimes resulted in greater accumulation of aflatoxin than when media were free of sorbate. Sorbate more effectively inhibited mold growth and aflatoxin production in medium M2 than M1 and when the small rather than the large inoculum was used. A second trial was done with 106 or 105 spores/flask of M2 (ca. 27 ml) and 105 spores/flask of M2 (ca. 27 ml) containing sorbate (200 ppm of sorbic acid). Cumulative data for mold growth. pH and content of aflatoxin in the medium showed that relative effects of different treatments changed during the incubation period. An index to measure the capacity of molds to synthesize aflatoxins was developed. Application of the index indicates that sorbate delayed mold growth but did not inhibit biosynthesis of aflatoxin. The ability to synthesize aflatoxin was greatest in the early stages of mold growth and then decreased linearly as mold growth progressed.

Antifungal Activity of Chitosan and Its Preservative Effect on Low-Sugar Candied Kumquat

1994 ◽  
Vol 57 (2) ◽  
pp. 136-140 ◽  
Author(s):  
SHAO W. FANG ◽  
CHIN F. LI ◽  
DANIEL Y. C. SHIH
Keyword(s):  
Shelf Life ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Inhibitory Effect ◽  
Life Extension ◽  
Potassium Sorbate ◽  
Mold Growth ◽  
Chitosan Concentration ◽  
Significant Difference ◽  
Order Polynomial

The inhibitory effect of chitosan, a deacetylated form of chitin, on the growth of Aspergillus niger and the aflatoxin production of Aspergillus parasiticus was evaluated. The inhibitory effect of chitosan against A. niger was increased as the chitosan concentration was increased from 0.1 to 5.0 mg/ml (pH 5.4). At concentrations of 4.0 or 5.0 mg/ml, chitosan was less effective than potassium sorbate in inhibiting the growth of A. niger. The greatest inhibitory effect of chitosan against A. parasiticus was found at 3.0–5.0 mg/ml. In addition, chitosan could completely prevent aflatoxin production by A. parasiticus at the concentration of 4.0–5.0 mg/ml. Chitosan (2.0 and 5.0 mg/ml) induced considerable leakage of UV-absorbing and proteinaceous material of A. niger at pH 4.8. Using the response surface methodology, a second order polynomial model was derived and used to predict the number of days to obtain visible mold growth under various combinations of chitosan concentrations and °Brix in candied kumquat. The results showed that there was no significant difference in shelf-life extension of candied kumquat at chitosan concentration of 3.5–6.5 mg/ml. However, °Brix had a significant effect on shelf life. Candied kumquat with 6.0 mg/ml chitosan concentration and 61.9° Brix had a predicted mold-free shelf life of 65.3 d.

Potassium Sorbate as a Fungistatic Agent In Country Ham Processing

1979 ◽  
Vol 42 (10) ◽  
pp. 780-783 ◽  
Author(s):  
J. D. BALDOCK ◽  
P. R. FRANK ◽  
PAUL P. GRAHAM ◽  
FRANK J. IVEY
Keyword(s):  
Relative Humidity ◽  
Drug Administration ◽  
Sorbic Acid ◽  
Fungal Growth ◽  
Growth And Yield ◽  
Potassium Sorbate ◽  
Mold Growth ◽  
Effective Level ◽  
Fungistatic Agent ◽  
Mold And Yeast

Sixty, seventy and ninety-day-old country cured hams were used to evaluate potassium sorbate as a fungistatic agent during aging and holding for market. A 1-min spray of 5% (w/v) potassium sorbate offered the lowest effective level for inhibition of fungal growth. Mold and yeast colony counts 30 days post-treatment were significantly lower than initial numbers but protection was lost by the 60th day under conditions conducive to fungal outgrowth (21 ± 5 C and 70 ± 5% relative humidity). Greater mold inhibition was noted when a 10% potassium sorbate spray was used under identical conditions. Less than 65% relative humidity inhibited mold growth on 120-day-old ham slices held at 7 C. Mold and yeast counts tended to be lower on hams treated after 60 days of processing than on hams treated after 90 days of processing. Residual concentrations of sorbic acid required to inhibit mold growth and yield an acceptable ham after 30 days storage were within the limit approved by the Food and Drug Administration for other food products.

Effects of Potassium Sorbate on Growth and Aflatoxin Production by Aspergillus parasiticus and Aspergillus flavus1

1983 ◽  
Vol 46 (11) ◽  
pp. 940-942 ◽  
Author(s):  
LLOYD B. BULLERMAN
Keyword(s):  
Aspergillus Flavus ◽  
Yeast Extract ◽  
Aflatoxin B1 ◽  
Spore Germination ◽  
Mycelial Growth ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Mycelial Mass ◽  
Yeast Extract Sucrose

Growth and aflatoxin production by selected strains of Aspergillus parasiticus and Aspergillus flavus in the presence of potassium sorbate at 12°C were studied. Potassium sorbate at 0.05, 0.10 and 0.15% delayed or prevented spore germination and initiation of growth, and slowed growth of these organisms in yeast-extract sucrose broth at 12°C. Increasing concentrations of sorbate caused more variation in the amount of total mycelial growth and generally resulted in a decrease in total mycelial mass. Potassium sorbate also greatly reduced or prevented production of aflatoxin B1 by A. parasiticus and A. flavus for up to 70 d at 12°C. At 0.10 and 0.15% of sorbate, aflatoxin production was essentially eliminated. A 0.05% sorbate, aflatoxin production was greatly decreased in A. flavus over the control, but only slightly decreased in A. parasiticus.

Hygroscopic Characteristics of Peanut Components and Their Influence on Growth and Aflatoxin Production by Aspergillus parasiticus

1984 ◽  
Vol 47 (10) ◽  
pp. 791-794 ◽  
Author(s):  
R. Y.-Y. CHIOU ◽  
P. E. KOEHLER ◽  
L. R. BEUCHAT
Keyword(s):  
Relative Humidity ◽  
Incubation Period ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Visible Growth ◽  
Atmospheric Relative Humidity ◽  
Time Required

Sound inshell runner-type peanuts, manually damaged inshell peanuts, shells, sound kernels, deskinned kernels and skins were stored in separate flasks under an atmospheric relative humidity of 100% at 28°C. After 5 d, water was adsorbed at levels of 1.2, 1.7, 3.9, 0.9, 1.0 and 9.5 g/100 g dry material, respectively. Surface disinfected components were inoculated with conidiospores of Aspergillus parasiticus NRRL 2999 and incubated under the same conditions. The time required for visible growth of the fungus was 8, 6, 4, 12, 10 and 3 d, respectively. The time for appearance of the conidiospores was 14, 10, 6, 16, 13 and 6 d. After a 3-wk incubation period, aflatoxin levels in peanut components were 111.4, 159.1, 4.4, 58.7, 99.0 and 1.5 μg/g, respectively.

Aflatoxin Production in a Meat Mix Model System in the Presence of Pediococcus and Lactobacillus

1992 ◽  
Vol 55 (8) ◽  
pp. 583-587 ◽  
Author(s):  
ROSA H. LUCHESE ◽  
JOSÉ F. P. MARTINS ◽  
WILKIE F. HARRIGAN
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Model System ◽  
Medium Composition ◽  
Mold Growth ◽  
Processing Conditions ◽  
Irradiated Meat ◽  
Incubation Temperatures

The effect on aflatoxin production by Aspergillus parasiticus of eight individual strains of Pediococcus and Lactobacillus was determined. The study was conducted in an axenic cultural system in which irradiated meat was employed in the formulation of a meat medium. The medium composition and incubation temperatures were simulations of Brazilian salami processing conditions. All single cultures of A. parasiticus supported aflatoxin production. More aflatoxin was produced in samples treated by the addition of lactic acid than in nontreated ones. Aflatoxin was not detected when A. parasiticus was grown with lactic acid bacteria, although visible mold growth was observed in all such cultures.

THE FEEDING OF FERMENTED COLOSTRUM TO NEONATAL CALVES. II. THE EFFECT OF VARYING THE TIME AND SEASON OF APPLICATION OF SORBIC ACID TO FERMENTED COLOSTRUM ON CALF PERFORMANCE

1980 ◽  
Vol 60 (4) ◽  
pp. 899-905 ◽  
Author(s):  
L. A. DREVJANY ◽  
O. R. IRVINE ◽  
G. S. HOOPER
Keyword(s):  
Crude Protein ◽  
Free Choice ◽  
Storage Temperature ◽  
Sorbic Acid ◽  
Potassium Sorbate ◽  
Mold Growth ◽  
Promoting Effect ◽  
Time Of Application ◽  
Calf Performance ◽  
Similar Growth

Three colostrum feeding trials involving 108 newborn Holstein calves were conducted in order to assess calf response to 1000 ppm of sorbic acid equivalent applied under various conditions. In the first two trials, the effect of colostrum storage temperature was tested. Calves were fed 2.25 L of colostrum inoculated with Streptococcus lactis once a day, together with 20% crude protein starter and water given free choice up to weaning (21 days). Potassium-sorbate-treated colostrum (1000 ppm of sorbic acid equivalent at day 4 of storage) resulted in better (P < 0.05) gains (300.6 vs. 199 g/day) and increased consumption of calf starter (502.9 vs. 410.6 g/day). Colostrum was stored at room temperature. Colostrum containing sorbic acid retained its palatability throughout the 21 days of the storage and was free of surface molds in contrast with the obvious mold growth on the surface of untreated colostrum. No similar growth-promoting effect due to sorbic acid was observed during trial 2 when the ambient temperature was 10.5 ± 1.2 °C and mold growth was inconsequential. As the antifungal effect of sorbic acid is a function of increasing pH and initial contamination, in trial 3 the effect of time of application on calf performance was tested. Calves were fed 2 L of colostrum cultured with S. lactis daily, free-choice water, and a calf starter containing 20% crude protein for 28 days. Similar growth response was obtained when potassium sorbate was applied at the beginning (day 1: high pH, low contamination) or end (day 4: low pH, higher contamination) of the collection period.

Quantitation of Growth of Mold on Cheese

1987 ◽  
Vol 50 (4) ◽  
pp. 337-341 ◽  
Author(s):  
AHMED E. YOUSEF ◽  
ELMER H. MARTH
Keyword(s):  
Aspergillus Parasiticus ◽  
Sorbic Acid ◽  
Cheddar Cheese ◽  
Mold Growth ◽  
Penicillium Camemberti ◽  
Solid Media ◽  
Constant Rate ◽  
Lag Period ◽  
Aseptic Conditions ◽  
Process Cheese

Earlier work by others indicated that a mold colony grows radially at a constant rate on solid media. This concept was used in our study to develop a method for quantifying growth of mold on cheese. The ability of molds to grow on cheeses or pasteurized process cheese made with or without addition of sorbate was compared. Cheeses tested were mild Cheddar, aged Cheddar, aged-smoked Cheddar, brick and pasteurized process cheese. Pasteurized process cheeses were made from the natural cheeses by addition of water and a phosphate salt, then the mixture was heated. Some pasteurized process cheese from mild Cheddar was made to contain 0–500 ppm sorbic acid. Natural cheeses were sliced under aseptic conditions and were placed in sterile petri-plates. The hot and molten pasteurized process cheeses were poured into petri-plates. A spore suspension of Aspergillus parasiticus or Penicillium camemberti was inoculated onto the center of the cheese slice or pasteurized process cheese, and plates were covered and incubated at 22°C. The radius of mold colonies was measured at 24-h intervals. Data were analyzed by linear regression and lag period and rate of radial growth were calculated. Mold colonies grew radially at constant rates on cheeses and pasteurized process cheese. Lag in growth of each mold was longest on aged Cheddar cheese and pasteurized process cheese made from it, whereas it was shortest on mild Cheddar, brick and pasteurized process cheeses made therefrom. A. parasiticus grew faster on all cheeses and pasteurized process cheeses than did P. camemberti. Aged Cheddar cheese and pasteurized process cheese made from it effectively slowed the growth of both molds that were studied. Pasteurized process cheese containing sorbic acid inhibited growth of both molds. Generally, the higher the concentration of sorbic acid in the pasteurized process cheese, the slower was mold growth and the longer was the lag period.

Growth and Aflatoxin Production by Aspergillus parasiticusNRRL 2999 as Affected by the Fungicide Iprodione1

1993 ◽  
Vol 56 (8) ◽  
pp. 718-721 ◽  
Author(s):  
AGUSTIN A. ARINO ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Yeast Extract ◽  
Aspergillus Parasiticus ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Mold Growth ◽  
Yeast Extract Sucrose ◽  
Different Levels ◽  
Mycelial Development

Spores of Aspergillus parasiticus strain NRRL 2999 were inoculated into yeast extract sucrose broth containing different levels of iprodione (0, 1, 3, 5, 10, 15, and 20 (μg/ml) and incubated at 25°C for 4, 7, 10, 14, and 21 d. Iprodione inhibited mold growth and subsequent toxin production, beginning at the 5 μg/g level up to 7 d of incubation. Results showed that as the iprodione level increased, more time was required by the organism to initiate mycelial development. At any given time, the lower the iprodione level, the more dry mycelial weight and aflatoxin production (B1, B2, G1, and G2) were observed.

Hazelnuts as Possible Substrate for Aflatoxin Production1

1988 ◽  
Vol 51 (4) ◽  
pp. 289-292 ◽  
Author(s):  
V. SANCHIS ◽  
Mª L. QUILEZ ◽  
R. VILADRICH ◽  
I. VIÑAS ◽  
R. CANELA
Keyword(s):  
Water Activity ◽  
Aspergillus Parasiticus ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Potassium Sorbate ◽  
Fungal Contamination ◽  
Activity Temperature ◽  
High Production

A study was carried out on the fungal contamination of commercially available hazelnuts, and the effect of different factors (water activity, temperature and presence of potassium sorbate) on fungal growth and aflatoxin production in hazelnuts. All samples (100%) of raw hazelnuts showed fungal contamination. None of the samples showed aflatoxin contamination, but when hazelnuts were inoculated with Aspergillus parasiticus, and water activity and temperature were optimal formold growth, high production of aflatoxin was found. Potassium sorbate at subinhibitory levels seemed to inhibit fungal growth, but enhanced aflatoxin production.

Effects of Phosphate Solutions on Aflatoxin Production in a Synthetic Medium and in Frankfurters†

1996 ◽  
Vol 59 (6) ◽  
pp. 626-630 ◽  
Author(s):  
S. KOTINEK MARSH ◽  
D. J. MYERS ◽  
H. M. STAHR
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin B1 ◽  
Aspergillus Parasiticus ◽  
Synthetic Medium ◽  
Aflatoxin Production ◽  
Mold Growth ◽  
Sodium Polyphosphate ◽  
Tetrasodium Pyrophosphate ◽  
Phosphate Solutions ◽  
Sodium Acid Pyrophosphate

Mold growth, sporulation, and aflatoxin B1 and G1 production were studied in Sabouraud dextrose agar (SDA) and frankfurters inoculated with Aspergillus flavus or Aspergillus parasiticus. Each of four phosphates, sodium polyphosphate glassy (SPG), sodium acid pyrophosphate (SAPP), tetrasodium pyrophosphate (TSPP), and Brifisol 414 (a blend of SPG, SAPP, and TSPP) were incorporated into the SDA (1 or 2%) or used as dipping solutions (5%) for the frankfurters. In SDA at 30°C, significant (P &lt; 0.05) reductions in aflatoxin B1 and G1 production by A. flavus and A. parasiticus occurred when 1% SPG, 1% TSPP, 1% Brifisol 414, and 2% SAPP were present. In frankfurters, A. flavus B1 aflatoxin production was increased with SAPP and TSPP.

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