scholarly journals The Use of Colors as an Alternative to Size in Mold Growth Studies

2018 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura
Keyword(s):  
Color Change ◽  
Fungal Growth ◽  
Area Measurement ◽  
Mold Growth ◽  
Growth Studies ◽  
Closed Systems ◽  
Imagej Software ◽  
Gray Values ◽  
Yeast Extract Agar ◽  
Rgb System

Size-based fungal growth studies have limitations. For example, the growth in size stops in closed systems once it reaches the borders and poorly describes the metabolic status, especially in the stationary phase. This might lead mycotoxin studies to unrealistic results. Color change could be a viable alternative as pigments are results of the mold’s metabolic activity. This study aimed to verify the possibility of using gray values and the RGB system to analyze the growth of Fusarium graminearum. It consisted color and area measurement using the ImageJ software for specimens grown in yeast extract agar (YEA). The results suggest the usability of color and gray values as reliable tools to analyze the growth of F. graminearum.

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.

scholarly journals Fusarium graminearum Colors and Deoxynivalenol Synthesis at Different Water Activity

Foods ◽  
2018 ◽  
Vol 8 (1) ◽  
pp. 7 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura
Keyword(s):  
Fusarium Graminearum ◽  
Color Change ◽  
High Growth ◽  
Cereal Crops ◽  
Color Analysis ◽  
Surface Color ◽  
Color Changes ◽  
White Mycelium ◽  
Imagej Software ◽  
Inverse Proportionality

Deoxynivalenol (DON) is a well-known mycotoxin, responsible for outbreaks of gastrointestinal disorders in Japan. Fusarium graminearum, a parasite of cereal crops, produces this toxin and this is one of the reasons why it is important to understand its metabolism. It is possible to predict the mold’s color change and the quantity of DON synthesized throughout its lifecycle. Furthermore, aw has been found to affect the amount of DON. This study aimed to analyze the potential of F. graminearum surface color as a predictor of DON concentration at aw = 0.94, 0.97, and 0.99. Thus, 36 specimens were incubated at 25 °C, 12 at each aw. After 4, 8, 12, and 16 days, three specimens from each aw were collected for color analysis and DON quantification. For color analysis, photos were taken and red, green and blue (RGB) channels were measured on ImageJ software. DON was quantified through liquid chromatography (HPLC). Color changes were only observed at aw = 0.99 because at lower aw the molds presented high growth of white mycelium. Yet, DON increased in all cases. It was only possible to relate the colors with DON concentration at aw = 0.99, where they presented inverse proportionality.

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.

scholarly journals RGB Imaging as Tool to Analyze the Growth of Fusarium graminearum in Infected Oats (Avena sativa) and Rice (Oryza sativa)

2019 ◽  
Author(s):  
Edgar Cambaza ◽  
Shigenobu Koseki ◽  
Shuso Kawamura
Keyword(s):  
Fusarium Graminearum ◽  
Color Change ◽  
Growth Models ◽  
Economic Losses ◽  
Selection Strategy ◽  
Imaging Analysis ◽  
Current Growth ◽  
Imagej Software ◽  
Pearson Correlations ◽  
Mycelial Phase

Fusarium graminearum is a cereal pathogen responsible for economic losses worldwide every year. An understanding of its growth is key to control its infection, but current growth models are limited because their size-based approach provides little information about the mold's metabolism. Recently, a RGB (red, green and blue) imaging analysis demonstrated the predictability of F. graminearum color change as it grows in yeast extract agar (YEA). This study aimed to verify the same phenomenon in oats (aw = 0.94, 0.97 and 0.99) and rice (aw = 0.97, 0.98 and 0.99). Photos were taken using a professional camera and a smartphone (iPhone 6) after incubation and during the subsequent 16 days, and average RGB was quantified using ImageJ software. The photos showed very similar color variations, regardless of the type of grain or aw. The mold first adopted a k-selection strategy by growing as a mycelium and then a r-selection strategy, increasing spore production. All RGB channels showed positive Pearson correlations between them (p < 0.001) and it was possible to design a model showing two lag phases, the first prior to a mycelial phase and the second prior to a sporular phase at the end of the experiment.

scholarly journals Antifungal potential of three natural oils and their effects on the thermogravimetric and chromatic behaviors when applied to historical paper and various commercial paper sheets

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 492-514
Author(s):  
Maisa M. A. Mansour ◽  
Mohamed Z. M. Salem ◽  
Rushdya Rabee Ali Hassan ◽  
Hayssam M. Ali ◽  
Dunia A. Al Farraj ◽  
...  
Keyword(s):  
Growth Inhibition ◽  
Antifungal Agents ◽  
Color Change ◽  
Linseed Oil ◽  
Fungal Growth ◽  
Gas Chromatography Mass Spectrometry ◽  
Citrus Reticulata ◽  
Natural Oils ◽  
Antifungal Potential ◽  
Commercial Paper

Three natural extracted oils from Citrus reticulata peels, C. aurantifolia leaves, and Linum usitatissimum (linseeds) were used as antifungal agents against the growth of Aspergillus flavus and Penicillium chrysogenum. The following main compounds (determined via gas chromatography–mass spectrometry) were found. The essential oil (EO) from C. aurantiifolia leaves contained limonene (22.96%), geranyl acetal (13.53%), and geraniol acetate (13.33%); the n-hexane oil from C. reticulata peels contained methyl-13-cyclopentyltridecanoate (16.74%), and D-limonene (16.06%); and linseed oil contained linoleic acid (27.36%), and oleic acid (19.01%). The inhibition of fungal growth significantly was reached 100% against A. flavus at all tested C. aurantifolia leaf EO concentrations and at a concentration of 2000 µL/mL for linseeds oil. The growth inhibition reached 100% against P. chrysogenum with C. aurantifolia leaf EO concentrations of 125-2000 µL/mL. Citrus reticulata peel EO had 100% growth inhibition of P. chrysogenum at concentrations of 2000 µL/mL and 1000 µL/mL, while linseeds oil had 100% growth inhibition at 2000 µL/mL. Thermogravimetric analysis showed that C. aurantifolia EO yielded the greatest thermal stability and color change protection to cotton pulp, while linseed oil was found to protect wood pulp-based and historical papers.

Combined testing approach to evaluate the antifungal efficiency of clove (Eugenia caryophyllata) essential oil for potential application in wood conservation

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 9474-9489
Author(s):  
Dana Mihaela Pop ◽  
Maria Cristina Timar ◽  
Emanuela Carmen Beldean ◽  
Anca Maria Varodi
Keyword(s):  
Essential Oil ◽  
Fungal Growth ◽  
Antifungal Treatment ◽  
Small Samples ◽  
Practical Case ◽  
Coverage Area ◽  
Sterile Culture ◽  
Before And After ◽  
Antifungal Efficiency ◽  
Imagej Software

The efficiency of clove (Eugenia caryophyllata) essential oil (C-EO) for the curative antifungal treatment of historic wood was investigated in comparison with two classical biocide products: a boron-based preservative (Diffusit S) and a formulation containing quaternary ammonium salts and isothiazole (Biotin T). A combined approach was adopted that consisted of implementation of C-EO in a practical case study on a degraded beech (Fagus sylvatica) wood artifact and evaluation of the treatment efficacy via an original laboratory mycological test. Small samples, extracted from the degraded wood material before and after curative treatments, were placed as inoculum on sterile culture medium and incubated for periodic monitoring of the emerging fungal growth for 140 d. Direct observation was supplemented with digital quantification of the fungal coverage area via ImageJ software and calculation of the absolute and relative indices of fungal development reduction. The results indicated that the C-EO solutions at both tested concentrations (10%, 5%) were more efficient than the considered reference products at similar concentrations (Diffusit S (10%) and Biotin T (5%)) for curative antifungal treatment. However, none of the treatments applied entirely prevented reactivation of the severe and complex fungal attack, which was highlighted by the mycological tests conducted on the control samples.

scholarly journals Chemical, biochemical, and microbiological aspects of chitosan quaternary salt as active coating on sliced apples

2012 ◽  
Vol 32 (3) ◽  
pp. 599-605 ◽  
Author(s):  
Douglas de Britto ◽  
Odilio Benedito Garrido Assis
Keyword(s):  
Color Change ◽  
Quaternary Salt ◽  
Fungal Growth ◽  
High Viscosity ◽  
Edible Coatings ◽  
High Solubility ◽  
Polymer Properties ◽  
Hue Angle ◽  
Active Coating ◽  
Microbiological Aspects

The biocompatibility of chitosan and chitosan quaternary salt coatings was evaluated for use as edible coatings for sliced apple. Measurement of water loss, color change, and fungal growth appearance were monitored as a function of time. A significant brownish effect was observed on chitosan coated slices, varying greatly from L* = 76.5 and Hue angle = 95.9° (t = 0) to L* = 45.3 and Hue angle = 69.8° (t = 3 days), whilst for TMC coated samples the variation was considerable lower (L* = 74.1; Hue angle = 95.0°) to (L* = 67.0; Hue angle = 83.8°) within the same period. The hydrosoluble derivative N,N,N-trimethylchitosan demonstrated good antifungal activity against P. expansum although highly dependent on the polymer properties such as degree of quaternization. The most efficient formulation was that prepared from derivative having a degree of quaternization of 45%, high solubility, and high viscosity. This formulation restrained fungus spreading up to 30%, while for the control it reached almost 80% of the total assessed surfaces during 7 days of storage.

Vital Fluorochromes as Tracers for Fungal Growth Studies

1995 ◽  
Vol 70 (2) ◽  
pp. 57-65 ◽  
Author(s):  
A. Stewart ◽  
J. W. Deacon
Keyword(s):  
Fungal Growth ◽  
Growth Studies
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