**3. Results and discussion**

In one of the literatures of the previous research, presence of fungi was tested in 34 samples collected from 3 silos. Results of this experiment proved that presence of fungi produced aflatoxins in majority of tested samples [5]. It is worth mentioning that fungi represent the main factors of starchy grain contamination (mycotoxigenic). Therefore, it has been found logical to review a study conducted by the authors on presence of fungi that have serious precedents as causes of diseases of respiratory system in humans. We will discuss the danger of these fungi to people dealing with wheat grains from the beginning of harvest until the

This part of the book will present results of a study conducted in one of the giant silos in Sakaka city, Al-Jouf region, Saudi Arabia, in the autumn of 2015. Our results will be discussed with results of previous studies in some countries in order to highlight some of the challenges

Twenty samples of wheat grains stored in the large silo in Sakaka were tested for the presence of fungi (part of this work has been reported elsewhere [7]). This was done by placing a known quantity of wheat in a bottle of sterile water next to the sampling area, taking care to ensure that one source of fungus (wheat grains) reaches the collection container. When returning to the laboratory, fungi were isolated by placing 5 ml of water mashed with fungal spores, coming from grain surfaces, in a 9-cm Petri dish and then adding 15 ml of rose-Bengal Potato Dextrose Agar (PDA) medium, all in isolation cabinet under aseptic conditions. Dishes were closed and sealed with parafilm to ensure full closure and placed upside down in plastic bags (previously sterilized by radiation) and incubated at 28°C, and then followed up until appearance of fungal colonies. After emergence of fungal colonies, each colony was purified on its own, to obtain pure single fungal isolate. Pure fungal samples were subjected to ophthalmic and microscopic examinations with imaging and arranged of figurative plates [8, 9]. Risk of isolated fungi has been tested on human health. Hemolytic ability of the isolated fungi to human red blood cells was tested following the method of [10, 11]. Fungal spore suspension (in 0.9% NaCl) was used. Washed (using 0.9% NaCl) 100 μl of blood, plus 900 μl of spore suspension was incubated, sodium chloride solution, which represents a negative control sample, and distilled water (positive control sample), under aseptic conditions, for comparison at 28°C, for 24 h, in the dark. Reaction mixtures were separated with the aid of a centrifuge and absorbance of supernatant was measured using UV-Vis spectrophotometer (spectro uv-2505) at 540 nm to calculate percentage of hemolysis of red blood cells following

%Hemolytic activity = absorbance of sample–absorbance of saline/absorbance of

dist.water × 100.

**2. Materials and methods a research on the presence of fungi in** 

**wheat stored in a silo in Sakaka city, Saudi Arabia**

entry into silos.

104 Global Wheat Production

formula of the equation:

facing safe storage of wheat grains inside silos.

Fungi of *Aspergillus flavus*, *A. niger*, *Circinella umbellata*, *Gliocladium* sp., *Penicillium frequentans*, *P. islandicum*, and *Ulocladium atrum* were isolated from wheat samples. **Table 1** shows prevalence of each fungus.


OR = Occurrence remarks; H = 60% -100.0%, M = 33 - 59.0%, L = 20–32%, and R = 7–19%.

**Table 1.** Gross counts of fungal genera and species derived from 20 samples of wheat grains collected from the main silo, Sakaka, Al-Jouf, Saudi Arabia by germs came from soaked grains in sterilized H<sup>2</sup> O, number of cases of isolation (NCl; out of 20 cases), occurrence remarks (OR), percentage of total counts (TC%) on PDA agar at 28°C.
