الفهرس 
Incidence of toxigenic molds in food productsOnly 14 pages are availabe for public view
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Abstract
Summary
Mycological survey was carried out to isolate and
identify the molds and aflatoxins (B1, B2, G1 and G2) that
present in cereal – derived products. One hundred samples
of cereal – derived products (50 samples of cereal – based
baby foods, for infants and young children, and 50 samples
of corn – based snacks), purchased from supermarkets and
small shops in Greater Cairo (al-qahira al-kubra), were used for fungal quantification, isolation, identification and analyzed for the presence of aflatoxins (B1, B2, G1 and )
using High Performance Liquid chromatography (HPLC). It was noticed that Aspergillus (41%), Penicillium
(16%), Alternaria (10%), Fusarium (8%) and Cladosporium (3%) were the prevalent genera in the
samples. Aflatoxin B1 (AFB1) could be detected in 14% of the
cereal– based baby foods samples and in 34 % of the corn – based snacks samples. Aflatoxin B2 (AFB2) could be
detected in 2% of the cereal – based baby foods samples and in 14% of the corn – based snacks samples. However,
numbers of contaminated cereal – based baby foods
samples with AFG1 and AFG2 were (6%) and (4%) respectively. Additionally, AFG1 and AFG2 were detected
in (18%) and (8%) of the corn-based snacks samples, respectively.
The results revealed the level of AFB1 in 13% of the samples examined was higher than the EU permission limit
(2 μg kg-1) and the daily intake, for all ages, of the products
of corn – based snacks (from 30 to 50 g), contaminated
with AFB1 is ranging from 0.42 to 23.75 ng kg-1 body weight per day, it is higher than the Provisional Maximum
Tolerable Daily Intake (PMTDI), 1.0 ng AFB1 kg-1 body weight for adult and children without hepatitis B. Also,
there is a significant risk for babies (6, 12 and 24 months),
who occasionally consumes a cereal – based food (30 g per day), from the most contaminated sample with aflatoxin B1,the estimated daily intake would be from 6.66 to 11.1 ng k
g-1 body weight per day and even in consumption of the less contaminated sample, the estimated daily intake is
from 1.62 to 2.7 ng k g-1 body weight per day. The foodborne mycotoxins with the greatest significance for human
health in developing countries is aflatoxins thus, routine
measurements of the toxin levels in foods should be carried
out to prevent their harmful effects on health. The activity of ten essential oils (cinnamon, cumin,
clove, fennel, garlic, lemon grass, marjoram, peppermint,
rosemary and thyme) were tested for their antifungal effect
against A. flavus growth using concentrations (10 and 20
μl/ well) by agar well diffusion method. The screening
results showed that the three essential oils cinnamon, garlic
and cumin exhibited high diameters of growth inhibition (44.7, 42.3 and 32.7 mm) respectively, at a dose of 10 μl of
the oil per well. However, the concentration of 20 μl of cinnamon and garlic essential oils inhibited the growth of A. flavus and the diameter of inhibition zone reached to
47.2 mm when the cumin essential oil is used. Also, Minimum Inhibitory Concentration (MIC) and
Minimum Fungicidal Concentration (MFC) for cinnamon, garlic and cumin essential oils were determined. Cinnamon
essential oil exhibited the maximum antimycotic activity with MIC and MFC values of 0.05 μl/ ml followed by
garlic essential oil with MIC value of 0.11 μl/ ml and MFC value 0.22 μl/ ml. Whereas, MIC for cumin essential oil
was 0.38 μl/ ml and MFC was 0.66 μl/ ml.
The effect of different concentrations (10, 20, 40, 60, 80 μl / 50 ml Czapek’s media) of essential oils (cinnamon,
garlic and cumin) on Aspergillus flavus growth and on aflatoxins Production in Czapek’s liquid media were
examined. There were a significant inhibitory effect (P<0.001) of cinnamon, garlic and cumin essential oils on growth of A. flavus and its aflatoxin production. Also, the
efficacy of various concentrations (10, 20, 40, 60 and 80 μl
/50 gm infected maize) of cinnamon, garlic and cumin essential oils on aflatoxins production in vivo, applied on maize grains infected by 106 spores of A. flavus was determined. The results showed that the great inhibition
effect of cinnamon essential oil on infected maize grains was at concentrations of 60 and 80μl / 50 gm infected maize, where the inhibition percentage was 100℅ for all
types of aflatoxins. Garlic essential oil showed the complete inhibition to aflatoxins production at 80μl EO
concentration. However, the concentration of 80μl cumin
essential oil showed complete inhibition for aflatoxins B2,
G1 and G2, while B1 was inhibited by 96.5%. Analysis of essential oils chemical compositions by
Gas chromatography Mass (GC-Ms) indicated that cinnamon essential oil had nearly fifteen major
components, the most components were: cinnamic aldehyde (72.87%) and cinnamic acid (8.88%). Garlic essential oil contains high content of dially trisulfide (34.29%) and dially disulfide (28.40%). However, cumin
essential oil had 14 major components includcuminaldhyde (24.80%), cumin-alcohol (20.19%) and Pcymen
(14.32%). Action of essential oils (cinnamon, garlic and cumin)
on cell structure were investigated under Transmission Electron Microscope, revealing that both cinnamon, garlic
and cumin essential oils had changed the shape of the cell and induced destruction of membranous organelles specially nuclei and mitochondria.