Preventing Growth of Potentially Toxic Molds Using Antifungal Agents1

1982 ◽  
Vol 45 (10) ◽  
pp. 953-963 ◽  
Author(s):  
LISA L. RAY ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Essential Oils ◽  
Aflatoxin Production ◽  
Potassium Sorbate ◽  
Phenolic Antioxidants ◽  
Residual Chlorine ◽  
Mold Growth ◽  
Penicillium Species ◽  
Mycotoxin Production ◽  
Antifungal Properties ◽  
Herbs And Spices

Mold inhibitors such as sorbates, propionates and benzoates have been used commercially for some time. Recently these and other potential inhibitors have been studied from the standpoint of their effects on growth of potentially toxic molds and mycotoxin production. In addition, other substances such as the antifungal antibiotic natamycin (pimaricin) and plant-derived products such as components of the essential oils of certain herbs and spices have recently been studied for their antifungal properties and effects on mycotoxin production. Some of these inhibitors inhibit mycotoxin production by greater than 70%, while only inhibiting growth of the mold by 25% or less. Of the organic acids, sorbic, propionic and benzoic, sorbic and its sorbate salts seems to be most effective over the widest range of conditions in preventing mold growth and mycotoxin production. Potassium sorbate is effective against toxic molds at levels of 0.10 to 0.15%. The antibiotic natamycin is very effective in preventing mold growth and toxin production at very low (0.001 to 0.005%) concentrations. A number of herbs and spices possess antifungal activity. At a level of 2.0%, in YES agar, cloves, cinnamon, mustard, allspice, garlic and oregano all completely inhibit mycotoxin production by a number of mycotoxigenic molds. Cloves, cinnamon and mustard seem to be the most effective of those tested, with complete inhibition occurring with amounts of spice less than 1%. Essential oils of orange and lemon also have antifungal properties at levels of 0.2 % and higher. Certain insecticides and fumigants also inhibit mold growth and mycotoxin production. The organophosphates naled and dichlorvos are both effective inhibitors at relatively low concentrations (0.002 to 0.01%). Phenolic antioxidants, particularly BHA, also inhibit toxic molds in concentrations of 0.025% and above. Naturally occurring methylxanthines, such as caffeine and theophylline, inhibit growth and aflatoxin production by A. parasiticus in concentrations of 0.1% and above. Chlorine, a commonly used sanitizer, will inactivate spores of toxic Aspergillus and Penicillium species at levels of residual chlorine commonly achieved with most sanitation procedures. Even though considerable information is available on inhibitory effects of a number of substances on mold growth and mycotoxin production, more work is needed to further define the conditions under which commercial antifungal agents are most effective in preventing growth of toxic molds and mycotoxin production.

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.

Formation and Control of Mycotoxins in Food

1984 ◽  
Vol 47 (8) ◽  
pp. 637-646 ◽  
Author(s):  
LLOYD B. BULLERMAN ◽  
LISA L. SCHROEDER ◽  
KUN-YOUNG PARK
Keyword(s):  
Drought Stress ◽  
Antifungal Activity ◽  
Mechanical Damage ◽  
Aflatoxin Production ◽  
Mold Growth ◽  
Fusarium Spp ◽  
Penicillic Acid ◽  
Animal Products ◽  
Mycotoxin Production ◽  
Penicillium Spp

Mycotoxin production is favored by high humidity and high water activity (aw). To control mycotoxin formation on the basis of moisture, the moisture content must be maintained below a certain critical level for each commodity. Aflatoxin production is favored by temperatures of 25 to 30°C, whereas below 8 to 10°C, aflatoxin production can occur, but the amounts produced are less and the time required for production is longer. Cycling or changing temperature may or may not increase aflatoxin production, depending on the temperatures, mold species and substrates involved. Other mycotoxic molds respond to temperature differently than the aspergilli. Species of Penicillium, Fusarium and Cladosporium are capable of growing at temperatures below 5°C, and some even just below freezing. Penicillium spp. can produce patulin, penicillic acid and ochratoxin at temperatures from 0 to 31°C, whereas Aspergillus ochraceus does not produce ochratoxin or penicillic acid below 12°C. Penitrem production by Penicillium crustosum can occur at refrigeration temperature. Fusarium spp. can produce zearalenone and the trichothecenes at temperatures below 10°C and even below freezing. Maintaining storage temperatures of stored commodities at 5°C or lower will prevent the production of aflatoxins and ochratoxin by aspergilli but will not prevent the production of mycotoxins by Penicillium spp. and Fusarium spp. Mycotoxic molds may grow on a vast array of substrates, but some substrates support little or no mycotoxin production while supporting extensive mold growth. Most substrates that support aflatoxin production are plant products, such as peanuts, Brazil nuts, pecans, walnuts, almonds, filberts, pistachio nuts, cottonseed, copra, corn sorghum, millet and figs. Animal products are less likely substrates for aflatoxin production. The main source of aflatoxins in animal products are residues in milk and animal tissues as a result of consumption of toxic feed by the animal. Some herbs and spices have antifungal properties and do not support mycotoxin production. However, aside from this, most food substrates are susceptible to mold growth and mycotoxin production. Some substrates, such as cheese, cured meats and soybeans, might be less favorable for mycotoxin production, but may still support mycotoxin formation. Drought stress, insect damage and mechanical damage may increase the ability of Aspergillus flavus and other fungi to invade peanuts, cottonseed and grain. Some measure of control can be gained by minimizing drought stress through irrigation and minimizing insect and mechanical damage. Development of peanut varieties and corn hybrids that are resistant to preharvest invasion by A. flavus may also offer some measure control. Competing microorganisms tend to restrict fungal growth and mycotoxin production. Low oxygen concentration (<1%) and/or increased concentrations of other gases (i.e., >90% CO2) may depress mold growth and mycotoxin formation. Antimycotic agents can be used to control mold growth and mycotoxin production. Sorbic acid, potassium sorbate, propionic acid and propionates appear to be more effective antimycotics over a greater range of conditions than benzoates. Other substances, such as sodium diacetate and BHA, also have antifungal activity. Certain herbs and spices, particularly cinnamon, cloves and mustard, may contain enough antifungal activity to exert a protective effect at normal usage levels.

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.

Inhibition of Mold Growth and Mycotoxin Production in High-Moisture Corn Treated with Phosphates

1989 ◽  
Vol 52 (5) ◽  
pp. 329-336 ◽  
Author(s):  
C. I. LEBRON ◽  
R. A. MOLINS ◽  
H. W. WALKER ◽  
A. A. KRAFT ◽  
H. M. STAHR
Keyword(s):  
Sodium Tripolyphosphate ◽  
Aflatoxin Production ◽  
Mold Growth ◽  
Powder Form ◽  
High Moisture Content ◽  
High Moisture ◽  
Sodium Polyphosphate ◽  
Tetrasodium Pyrophosphate ◽  
Mycotoxin Production ◽  
Spray Form

Mold growth and mycotoxin production were studied in high-moisture (20%) corn treated with tetrasodium pyrophosphate (TSPP); acid and alkaline sodium polyphosphate, glassy (SPG), also known as sodium hexametaphosphate; sodium tripolyphosphate (STPP); and tricalcium phosphate. Six mold cultures belonging to the genera Aspergillus, Fusarium, and Penicillium were tested in corn varieties highly resistant or highly susceptible to mold infection in the field, and in a mixture of five other varieties of corn. The acidic SPG, as well as TSPP and STPP totally prevented or reduced mold growth when added in powder form to corn at 1.0% or 2.0% (w/w), regardless of corn variety and high moisture content. Phosphates afforded protection in whole and damaged kernels. Similar results were obtained with 2.0% acidic SPG and TSPP when added in spray form. Whenever mold growth occurred, treatment of corn with 1.0% or 2.0% (w/w) TSPP and acidic or alkaline SPG inhibited (P<0.01) aflatoxin production by aspergilli.

Prevention of Mold Growth and Toxin Production through Control of Environmental Conditions

1982 ◽  
Vol 45 (6) ◽  
pp. 519-526 ◽  
Author(s):  
MARTIN D. NORTHOLT ◽  
LLOYD B. BULLERMAN
Keyword(s):  
Environmental Conditions ◽  
Low Temperatures ◽  
Great Influence ◽  
Fungal Growth ◽  
Aflatoxin Production ◽  
Toxin Production ◽  
Mold Growth ◽  
Penicillic Acid ◽  
Mycotoxin Production ◽  
O2 Concentration

Environmental conditions influence mold growth and mycotoxin production. Such things as water activity (aw), temperature, pH and atmosphere can strongly affect and profoundly alter patterns of growth and mycotoxin production. Generally, maintenance of low temperatures will prevent aflatoxin production in stored products, whereas other toxins such as penicillic acid, patulin, zearolenone and T-2 toxin may be produced at low temperatures. Toxic Penicillium and Fusarium species are generally more capable of growth at low temperatures than are toxic species of Aspergillus. Temperature interacts with aw to influence mold growth and mycotoxin production. Aflatoxin B1 can be produced at conditions of aw and temperature which are close to the minimum aw and temperature for growth. On the other hand, patulin, penicillic acid and ochratoxin A are produced within a narrower range of aw and temperature, compared with those for growth. In fact, production of patulin and penicillic acid by Penicillium species appears to be confined to high aw values only. In optimal substrates, the minima of aw and temperature for growth and toxin production may be lower than in other substrates. It appears that pH and substrate composition have no great effect on growth of toxic molds, but may have a great influence on toxin production. Presence of CO2 and O2 influences mold growth and mycotoxin production. A 20% level of CO2 in air depresses aflatoxin production and markedly depresses mold growth. Decreasing the O2 concentration of air to 10% depresses aflatoxin production, but only at O2 levels of less than 1% are growth and aflatoxin production completely inhibited. With patulin- and sterigmatocystin-producing molds, concentrations of 40% CO2 depress growth and toxin production, but a level of 90% CO2 is needed to completely inhibit production of these toxins. Decreasing O2 concentration to 2% depresses production of patulin and sterigmatocystin but does not affect fungal growth. Only at levels down to 0.2% are growth and toxin production completely inhibited. Controlled atmospheres with increased CO2 (above 10%) and decreased O2 (2%) can be used to retard mold growth. Exclusion of O2 by vacuum packaging in materials with low O2 permeability will depress or even prevent aflatoxin production. Presence of other microorganisms may also restrict fungal growth and mycotoxin production. Aflatoxin production by Aspergillus flavus in mixed cultures with Aspergillus niger is less than in pure culture. Mixtures of fungi growing in grains and nuts in competition with A. flavus seem to prevent aflatoxin production. Other organisms including Rhizopus nigricans, Saccharomyces cerevisiae, Brevibacterium linens and some lactic acid bacteria have been shown to reduce growth and aflatoxin production by Aspergillus parasiticus. In general, mold growth and mycotoxin production can be prevented by employing various measures based on knowledge of the factors involved. Choice of the measures depends upon the type of product, storage period and available techniques.

scholarly journals Effect of Temperature during Drying and Storage of Dried Figs on Growth, Gene Expression and Aflatoxin Production

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 134
Author(s):  
Ana Isabel Galván ◽  
Alicia Rodríguez ◽  
Alberto Martín ◽  
Manuel Joaquín Serradilla ◽  
Ana Martínez-Dorado ◽  
...  
Keyword(s):  
Gene Expression ◽  
Aflatoxin Production ◽  
Effect Of Temperature ◽  
Mycotoxin Production ◽  
Industrial Processing ◽  
Factors Associated ◽  
Different Temperatures ◽  
Major Producer ◽  
Main Factors ◽  
And Storage

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.

scholarly journals Investigation of the Antifungal and Anti-Aflatoxigenic Potential of Plant-Based Essential Oils against Aspergillus flavus in Peanuts

2020 ◽  
Vol 6 (4) ◽  
pp. 383
Author(s):  
Premila Narayana Achar ◽  
Pham Quyen ◽  
Emmanuel C. Adukwu ◽  
Abhishek Sharma ◽  
Huggins Zephaniah Msimanga ◽  
...  
Keyword(s):  
Essential Oils ◽  
Aspergillus Flavus ◽  
High Performance ◽  
Opportunistic Infections ◽  
Aflatoxin Production ◽  
The United States ◽  
Microscopy Study ◽  
Aspergillus Species ◽  
Gas Chromatography Mass Spectrometry ◽  
Ammonia Vapor

Aspergillus species are known to cause damage to food crops and are associated with opportunistic infections in humans. In the United States, significant losses have been reported in peanut production due to contamination caused by the Aspergillus species. This study evaluated the antifungal effect and anti-aflatoxin activity of selected plant-based essential oils (EOs) against Aspergillus flavus in contaminated peanuts, Tifguard, runner type variety. All fifteen essential oils, tested by the poisoned food technique, inhibited the growth of A. flavus at concentrations ranging between 125 and 4000 ppm. The most effective oils with total clearance of the A. flavus on agar were clove (500 ppm), thyme (1000 ppm), lemongrass, and cinnamon (2000 ppm) EOs. The gas chromatography-mass spectrometry (GC-MS) analysis of clove EO revealed eugenol (83.25%) as a major bioactive constituent. An electron microscopy study revealed that clove EO at 500 ppm caused noticeable morphological and ultrastructural alterations of the somatic and reproductive structures. Using both the ammonia vapor (AV) and coconut milk agar (CMA) methods, we not only detected the presence of an aflatoxigenic form of A. flavus in our contaminated peanuts, but we also observed that aflatoxin production was inhibited by clove EO at concentrations between 500 and 2000 ppm. In addition, we established a correlation between the concentration of clove EO and AFB1 production by reverse-phase high-performance liquid chromatography (HPLC). We demonstrate in our study that clove oil could be a promising natural fungicide for an effective bio-control, non-toxic bio-preservative, and an eco-friendly alternative to synthetic additives against A. flavus in Georgia peanuts.

Inhibition of Aspergillus spp. and Penicillium spp. by Fatty Acids and Their Monoglycerides

2007 ◽  
Vol 70 (5) ◽  
pp. 1206-1212 ◽  
Author(s):  
CLELIA ALTIERI ◽  
DANIELA CARDILLO ◽  
ANTONIO BEVILACQUA ◽  
MILENA SINIGAGLIA
Keyword(s):  
Fatty Acids ◽  
Fungal Growth ◽  
Lag Time ◽  
Mold Growth ◽  
Penicillium Species ◽  
Colony Diameter ◽  
Gompertz Equation ◽  
Lag Times ◽  
Penicillium Spp ◽  
Palmitic Acids

The antifungal activity of three fatty acids (lauric, myristic, and palmitic acids) and their monoglycerides (monolaurin, monomyristic acid, and palmitin, respectively) against Aspergillus and Penicillium species in a model system was investigated. Data were modeled through a reparameterized Gompertz equation. The maximum colony diameter attained within the experimental time (30 days), the maximal radial growth rate, the lag time (i.e., the number of days before the beginning of radial fungal growth), and the minimum detection time (MDT; the number of days needed to attain 1 cm colony diameter) were evaluated. Fatty acids and their monoglycerides inhibited mold growth by increasing MDT and lag times. The effectiveness of the active compounds seemed to be strain and genus dependent. Palmitic acid was the most effective chemical against aspergilli, whereas penicilli were strongly inhibited by myristic acid. Aspergilli also were more susceptible to fatty acids than were penicilli, as indicated by the longer MDT.

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