**9. Determination of total fumonisins contamination in stored maize grain samples collected from some selected growing areas of Bangladesh**

The study was conducted at the Laboratory of Department of Plant Pathology, Bangladesh Agricultural University, Mymensingh. Composite stored maize grains samples were collected from 15 maize growing areas of Bangladesh such as Panchagarh, Thakurgaon, Dinajpur, Nilphamari, Rangpur, Lalmonirhat, Gaibandha, Bogura, Natore, Kushtia, Jashore, Chuadanga, Kishoreganj, Manikganj, Cumilla.

Fumonisins were detected with the highest value recorded in Gaibandha (9.18 mg/kg) and the lowest in Cumilla (0.11 mg/kg) (**Table 3**). Panchagarh (1.47 mg/kg), Thakurgaon (1.27 mg/kg), Dinajpur (0.65 mg/kg), Nilphamari (1.28 mg/kg), Rangpur (1.65 mg/kg), Lalmonirhat (1.18 mg/kg), Bogura (1.29 mg/kg), Kushtia (1.44 mg/kg), Kishoreganj (1.54 mg/kg), and Manikganj (1.47 mg/kg) had moderately high fumonisin levels revealing statistically identical data. Other regions showed indentically dissimilar data except Natore (0.23 mg/kg) and Chuadanga (0.59 mg/kg) (**Table 3**).

Infection rate of *Fusarium* spp. had the highest value in Bogura (13.50 %) followed by Gaibandha (13.25 %), Nilphamari (12.50 %) depicted statistically similar data and the minimal was found in Chuadanga (0.50 %) and Kustia (0.56 %). Moderately higher levels of fumonisin detected in Panchagarh (2.63 %), Thakurgaon (6.06 %), Dinajpur (2.38 %), Rangpur (9.69 %), Jessore (2.25 %), Kishoreganj (17.88 %), Manikganj (6.94 %) and Cumilla (5.31 %) were in the group of ststistically identical data. Moderate but less high and statistically similar results showed in Thakurgaon (6.06 %) and Manikganj (6.94 %) (**Table 3**).

The outmost percent fumonisins concentration over standard limit was found in Rangpur (65 %) followed by Kishoreganj (53.5 %), Gaibandha (47.5 %), Manikganj (47 %), Kushtia (45 %), Panchagarh (46.5 %), Bogura (28.5 %), Thakurgaon (27 %), Nilphamari (27 %), Lalmonirhat (18 %) revealing that the aflatoxins contamination from those area were beyond the regulatory limit set by EU for fumonisins (1 ppm), conversely, fumonisins concentration from other five locations were below the regulatory limit of fumonisins (1 ppm) (**Table 3**).

### **9.1 Relationship between fumonisins producing** *Fusarium* **spp. and mean fumonisin concentrations**

The regression analysis between *Fusarium* spp. infected maize grains and mean fumonisin concentrations which was positively correlated by observing regression equation where the slope was = 0.038 and y-intercept was = 0.882, coefficient of


*\*Significant at 5% level of significance. Least significant difference (LSD) at P = 0.05 was used for comparing means and the P values were 0.00.*

*\*\*Significant at 1% level of significance. Least significant difference (LSD) at P = 0.05 was used for comparing means and the P values were 0.00. Data are the averages of three biological replications. The regulatory limits for fumonisin is 1 ppm (1 mg/kg).*

### **Table 3.**

*Levels of total fumonisins concentration in stored maize grains collected from the stores of traders of fifteen maize growing areas of Bangladesh.*

determination, R2 = 0.198 and coefficient of correlation, r = 0.45 which depicted that 1 percent surges of *Fusarium* in maize grains ultimately rised 0.038 mg/kg fumonisins concentration. In terms of 5 % surges of *Fusarium* in maize grains, the fumonisins concentration was increased up to 0.19 mg/kg and when *Fusarium* increased 20 % in maize grains, the fumonisins concentration was escalated up to 0.76 mg/kg (**Figure 4**).

### **9.2 Identification of** *Fusarium* **species from the stored maize grain samples collected from some selected growing areas of Bangladesh**

Morphological identification of *F. oxysporum* and *F. proliferatum* were detected by using petridish and culture plate method as well as observing microscopic figures under compound and stereo microscope (**Figure 2B(a)-(f )**). Fifteen fungal isolates were identified using primers specific to ITS 1 and ITS 4 region. PCR assays of *F. oxysporum* DNA with ITS 1 and ITS 4 primers amplified a single fragment of about 600 bp which revealed that all the isolates obtained were fungi (**Figure 5A**). Sequence analysis of ITS region by BLAST program revealed that all the isolates obtained from maize were belong to *F. oxysporum* and *F. proliferatum*.

*Aflatoxins and Fumonisins Contamination of Maize in Bangladesh: An Emerging Threat… DOI: http://dx.doi.org/10.5772/intechopen.101647*

**Figure 4.** *Linear correlations between* Fusarium *infected maize grains and total fumonisin concentration.*
