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© 2020 by the authors; licensee Asian Online Journal Publishing Group 
 

Agriculture and Food Sciences Research 
Vol. 7, No. 1, 58-64, 2020 

ISSN(E) 2411-6653/ ISSN(P) 2518-0193 
DOI: 10.20448/journal.512.2020.71.58.64 

© 2020 by the authors; licensee Asian Online Journal Publishing Group 

    
 

 
 
 
Occurrence of Fumonisins in Some Maize Meal Marketed to Consumers in Harare, 
Zimbabwe 

 
Princess Mushonga1    

Wilson Parawira2    

Loveness Kuziwa Nyanga3    

  
( Corresponding Author) 

 
1,2Department of Biological Sciences, Faculty of Science and Engineering, Bindura University of Science 
Education, Chimurenga Road, Bindura, Zimbabwe. 

 
3Institute of Food, Nutrition and Family Science, University of Zimbabwe, Mount Pleasant, Harare, Zimbabwe. 

 
Abstract 

Mycotoxins are toxic secondary metabolites secreted by filamentous fungi which affect animals, 
plants and humanscausing a lot of diseases. Fumonisins are the types that mostly affect cereal 
grains. The prevalence of fumonisins in Harare marketed maize meal was investigated in 72 
randomly selected samples. Fumonisin B1 and Fumonisin B2 were extracted from maize meal 
with methanol-water (3:1, v/v) using ultrasonic extraction. They were injected into an LC-MS 
system following centrifugation. A survey was also conducted to determine the measures taken by 
5 major Harare millers to mitigate fumonisin contamination in the maize meal. Fumonisin B1 
(FB1) was detected in all analysed samples at mean concentrations ranging between 61.45 and 
265.79 µg/kg. Fumonisin B2 (FB2) was detected in only 56.9 % of the samples analysed, with a 
range between 13.72 µg/kg and 76.93 µg/kg. The highest total fumonisin mean concentration 
(FB1+FB2) was detected in maize meal with maize bran added to it (342.72 µg/kg), while the 
least total fumonisin mean concentration was detected in maize meal with wheat bran added to it 
(61.45 µg/kg). All the samples analysed were within the maximum tolerable limit (MTL) of 1000 
µg/kg. However, the average probable daily intake (APDI) of fumonisins ranged between 0.82 
and 4.57 µg/kg body weight/day. Maize meal with maize bran added and Roller meal had PDMI 
above the regulatory limit of 2 µg/kg body weight/day recommended by the World Health 
Organisation. The high frequency of fumonisins consumed daily in these two types of maize meal 
could be posing some health risks to consumers.  

 
Keywords: Mycotoxins, Maize meal, Fumonisins, Milling, Risk assessment, World Health Organisation, Zimbabwe. 

 
Citation | Princess Mushonga; Wilson Parawira; Loveness Kuziwa 
Nyanga (2020). Occurrence of Fumonisins in Some Maize Meal 
Marketed to Consumers in Harare, Zimbabwe. Agriculture and 
Food Sciences Research, 7(1): 58-64. 
History:  
Received: 22 January 2020 
Revised: 28 February 2020 
Accepted: 31 March 2020 
Published: 5 May 2020 
Licensed: This work is licensed under a Creative Commons 

Attribution 3.0 License  
Publisher:  Asian Online Journal Publishing Group 
 

Acknowledgement: The authors would like to acknowledge the support they 
got from Bindura University of Science Education and the Pharmacy 
Department of the University of Zimbabwe for all the assistance throughout 
our work. Authors also want to thank all the interviewed Milling Companies 
for the information they provided for the successful completion of their work. 
Authors are indebted to Mr. C. Mutsimhu, Dr. B. Masamha and Mr. K. Basira 
who assisted them with the Statistical analyses. 
Funding: This study received no specific financial support. 
Competing Interests: The authors declare that they have no conflict of 
interests. 
Transparency: The authors confirm that the manuscript is an honest, 
accurate, and transparent account of the study was reported; that no vital 
features of the study have been omitted; and that any discrepancies from the 
study as planned have been explained. 
Ethical: This study follows all ethical practices during writing.   

 

 

Contents 
1. Introduction ...................................................................................................................................................................................... 59 
2. Materials and Methods ................................................................................................................................................................... 59 
3. Results and Discussion ................................................................................................................................................................... 60 
4. Conclusion ......................................................................................................................................................................................... 63 
References .............................................................................................................................................................................................. 63 
 

 
 
 

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Contribution of this paper to the literature 
The levels of fumonisins in all the maize meal analyzed in this study were below the maximum 
tolerable limits of 1 000 µg/kg set by the European Union. However, the APDI of fumonisins 
estimated for maize meal with maize bran added and roller meal were above the provisional APDI set 
by WHO. Maize meal with maize bran added and Roller meal showed high contamination levels 
probably because they contained the bran and some germ that are highly contaminated by fumonisins. 
The high frequency of fumonisins consumed daily in both types of maize meal pose some health risks to 
consumers. There is need for setting up measures to check the quality of maize-based foods in order to 
alleviate the dangers of developing esophageal cancer and other probable health complications that are 
a result of fumonisin contamination. 

 
1. Introduction 

Maize (Zea mays L) is an economically significant cereal that is grown in Zimbabwe. It serves as the staple diet 
for the majority of the Zimbabwean populace. Maize is nutritionally important since it is an excellent source of 
proteins, starch, lipids, some bioactive compounds and some phytochemicals [1]. Maize may contain a number of 
important B vitamins, folic acid, Vitamin C, and provitamin A (i.e., precursor to vitamin A). Maize is also rich 
in phosphorus, magnesium, manganese, zinc, copper, iron and selenium, and has small amounts 
of potassium and calcium. It can be consumed as raw grain or processed into maize meal. However, safety can be 
greatly compromised when the maize grains are contaminated by fumonisins, the secondary organic metabolites 
secreted by Fusarium species [2].  

Fumonisin B1, B2 and B3 are the most predominant of all fumonisins and are often detected in maize and maize 
products [3]. A considerable volume of research on mycotoxins has been carried out in Zimbabwe on maize and 
studies have shown that fumonisin B1 mainly contaminates the maize grains before and after harvest [3, 4]. 
Fumonisin B1 which accounts for nearly 70 % of food contamination worldwide [5] is the most pernicious of the 
fumonisins. It has been associated with hepatocellular and oesophageal cancers, neural tube defects and impaired 
growth in children [6]. The B-series of fumonisins are generally thermo-stable at temperatures below 150 ºC but 
their concentrations get significantly lower at temperatures above this value [2]. 

Insects, such as the maize stalk borer (Busseola fusca), infest maize cobs in the field and subsequently cause 
contamination of the grains by spreading mycotoxigenic fungi [7]. When water activity is high (aw> 0.9), 
fumonisins are synthesised in maize before harvesting [8]. It is of paramount importance that maize kernels are 
adequately dried prior to milling in order to minimise the chances of contamination by the fumonisin-producing-
fungi.  

Milling is a process that transforms grains into smaller consumable particles, such as maize meal, grits or 
starch.  The milling process does not detoxify fumonisins, instead it re-distributes them, giving rise to higher or 
lower concentrations in the various milled fractions [9]. Studies have shown that the germ and the hull of the 
maize kernels harbour very high levels of fumonisins compared to the endosperm [10, 11].   

Zimbabwean milling companies buy maize from the Grain Marketing Board. They mill and package the maize 
meal which is then sold in the supermarkets. Recently, there has been an improvement in the nutritional 
composition of maize meal produced by some companies. Some are adding wheat bran or maize bran to the 
processed maize meal so as to enhance the fibre levels in their products. However, the brans might bring with them 
mycotoxins which contaminate the maize meal and pose some health risks to the consumers [12].   

Fumonisins have been found to be the most prevalent mycotoxin in Zimbabwe. However, not much research 
has been done to determine levels of fumonisins in maize meal. The high frequencies of fumonisins observed in 
Zimbabwean maize grain are a cause for concern to human health [4]. Therefore, it is most appropriate to quantify 
the fumonisin levels in maize-meal since it is a direct product of maize consumed by many Zimbabweans. The 
findings will help to raise awareness on the levels and dangers of fumonisins in the different types of maize meal 
being consumed in the country. 
 

2. Materials and Methods 
2.1. Study Area  

The study was conducted in Harare, Zimbabwe where maize meal was bought from three different 
supermarkets. These three supermarkets represented the major supermarkets selling maize meal to the population 
(2 123 132 people) in Harare (ZimStat. Census 2012: Provincial report). The supermarkets were selling maize meal 
from the Zimbabwean millers. Further, a survey was carried out on five major Zimbabwean millers to establish the 
mitigation measures during the milling process to reduce fumonisin contamination. Analysis of the maize meal 
samples was done at the laboratory of the Pharmacy Department of the University of Zimbabwe, Harare.  
 

2.2. Experimental Design 
This study used a descriptive approach. Quantitative observations were done by analysing and recording of 

quantifiable levels of fumonisin B1 and fumonisin B2 in the maize meal which was randomly purchased from Harare 
supermarket between September and December, 2018 from 5 different grinders/millers. Analysis of variance 
(ANOVA) was used to statistically analyse the results. Qualitative observation was done on the survey research. 
Both the quality controllers and those who were milling (millers) answered to questionnaires with both open-ended 
and close-ended questions which mainly focussed on the measures taken by these 5 millers to mitigate the effects of 
fumonisin and other mycotoxins contamination in maize meal. 
 

2.3. Sampling of Maize Meal 
From each of the five major Zimbabwean millers (M1, M2, M3, M4, M5), 2 kg maize-meal packets, 3 of each 

type (roller meal and super refined), were collected randomly from each of the three selected major supermarkets. 
In addition, 2 kg packets of each of super refined maize meal with wheat bran or maize bran were also collected 
from miller 2 using the same procedure as above.  



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One hundred grams of each type of maize meal were drawn from each of the 2 kg packets at 3 points (bottom, 
middle and top of the pack). Similar types of maize meal samples collected from each individual miller were 
thoroughly mixed together at the laboratory of the Pharmacy Department, University of Zimbabwe. The mixed 
samples were sealed in sterile plastic bags and stored at 20 ºC until further analysis. 
 

2.4. Fumonisin Extraction from Maize Meal Samples  
Fumonisin extraction was done according to the protocol by Li, et al. [13] with Ultrasonic extraction which 

was modified. Maize meal samples were blended and 5 g of homogenized maize meal were mixed with 25 ml of 
Extraction Solvent (methanol/water) in the ratio 3:1 (v/v). Triphenyl phosphate (TPP) was used as the internal 
standard. Samples were shaken by hand for 5 minutes and centrifuged at 4000 rpm for 5 minutes using a Hettich 
Zentrifugen (Germany) centrifuge. The supernatant was placed into a 5 ml syringe. It was then filtered, through a 
0.22 mm acrodisc syringe filter, into an HPLC vial for LC-MS analysis. 
 

2.5. Calibration of Standards 
Five grams (5g)  of  Blank  (Probrand) Corn (corn without any fumonisin) were transferred into a 50 ml falcon 

tube. The calibration standards  and Quality Control Samples were matrix-matched by spiking known volumes of 
standards of  FB1 and FB2 into blank samples to target concentrations  5 ng/ml, 10 ng/ml, 50 ng/ml, 100 ng/ml, 
500 ng/ml, 1000 ng/ml, 2000 ng/ml, 3000 ng/ml and 5000 ng/ml. This was done using 25 ml (methanol/water) 
in the ratio 3:1 (v/v) as the diluent in which Triphenylphosphate (TPP) was used as the internal standard at 500 
ng/ml. The tubes containing the sample and extraction solvent were capped and shaken vigorously for 5 minutes. 
They were further centrifuged for 5 minutes at 4000 rpm. The supernatant was put into a 5 ml syringe  and then 
filtered through 0.22 mm syringe filters into the vials for  HPLC-MS analysis. 

A calibration curve was made using 9 standards starting with 1000 ng/ml as stock. Spiked samples were 
produced to validate the method using QC standards: HQC-4000 µg/kg; MQC-2000 µg/kg; LQC- 50 µg/kg. 
 

2.6. HPLC-MS Conditions for Fumonisin Analysis 
The HPLC used was  Agilent HPLC 1260 System (California, USA) equiped with a binary pump, autosampler 

and thermostated column compartment. A Phenomenex, Luna Column  with dimmesions 50 x 2 mm, 3 micron was 
used for separation of the compounds. Mobile Phase A comprised 5 mM Ammonium acetate; pH was adjusted with 
16 ml formic acid to 3.1. Mobile Phase B consisted of 100 % methanol. The temperature of the column was 

maintained at 40 ℃ . The flow rate was 0.45 ml/minute while the injection volume was 80 µl. Fifty percent 
methanol was used for needle wash. Run time was set at 10 min. All the fumonisins eluted at 7.2 - 7.8 min. 

 Agilent Q-TOF 6530 Mass spectrometer was used for detection of fumonisins.  It was fitted with an 
electrospray ionisation (ESI) probe and operated in the positive ionisation mode. The following parameters were 
optimised: capillary voltage, 4000V; drying gas temperature, 350 ºC and desolvation gas flow rate, 10 l/min. Data 
acquisition and analysis was done using the Mass Hunter software version B.07.03 (509). 
 

2.7. Method Validation 
An ‘in house’ validation was applied according to the internal procedure as well as the acceptance criteria for 

Bio-analytical Method Development and Validation. Intra-day accuracy (97.54 %), linearity (0.995-0.999) and 
precision (2.78%) of the quality control (Q C) samples for Fumonisin B1 and Fumonisin B2 were within the accepted 
range. Inter-day quality control samples for both Fumonisin B1 and Fumonisin B2 also passed the acceptance 
criteria. The average recoveries for all quality control samples were between 85 % and 96 %. Percent Coefficient of 
Variation was less than 2.78 % for all QC samples. Calibration curves for both Fumonisin B1 and Fumonisin B2 
showed that linearity were greater than 0.9900 according to the set regulations for method development and 
validation. Limit of detection for Fumonisin B1 and Fumonisin B2 were 5µg/kg. In this regard, the LC-MS method 
developed passed all the acceptance criteria in accordance with FDA principles for method validation and related 
regulations; therefore it was fit for routine sample analysis for fumonisins in maize meal.  
 

2.8. Estimation of the Probable Average Daily Intake of Fumonisins in the 4 Types of Maize Meal 
The estimation of the probable average daily intake (APDI) was done by calculating the average probable daily 

intake of FB1 and FB2 combined in the samples. The estimates of the average probable daily intake (APDI) of FB1 
and FB2 combined in the samples were calculated using the formula: 

APDI=L×D/60kg, where: 
APDI is the average probable daily intake. L is the mean total concentration of FB1+FB2 in the maize meal 

samples. D is daily consumption of maize meal - average of 800g [3, 4]. The proposed typical body weight of an 
adult was 60kg. 

 

2.9. Data Analysis 
Quantitative data were analyzed using Unbalanced Analysis of variance (ANOVA) performed in Genstat 

Version 19. Mean differences in the levels of fumonisin contamination were determined using least significant 
differences (LSD) at 5% level of significance. An Unbalanced Design ANOVA was used because there was no equal 
number of observations since some fumonisin quantities were below the limit of detection. The qualitative data 
collected using the questionnaires were analyzed using content analysis.  

 

3. Results and Discussion 
3.1 Survey Results 

A questionnaire was administered to the millers and quality controllers of each milling company to establish 
the mitigation measures these milling companies were taking to reduce the levels of fumonisins in their maize meal 
and the responses are summarized in Table 1. Most of them knew very little about fumonisins, instead, during their 

quality checks they focused on aflatoxins, which are less abundant in Zimbabwean maize than fumonisins [3, 4]. 



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Their lack of knowledge about fumonisins may pre-dispose the maize meal consumers to health risks from 
fumonisin contamination. Millers were not monitoring fumonisin levels in both the maize and the maize meal. This 
has potentially detrimental effects on the consumer’s health.  Mwalwayo and Thole [14] stressed the co- 
occurrence of aflatoxins with fumonisins in maize; therefore millers need to use cheaper and effective methods of 
testing for multiple mycotoxins in the maize meal, such as the liquid chromatography mass spectrometry technique 
(HPLC/MS) [15]. All the millers were sorting and cleaning the maize kernels prior to milling. They did the 
sorting to remove physically damaged and infected grain based on physical damage and the presence of moulds. 
Cleaning of the maize was done to remove cobs, chuff and stones. The sorting could explain the lower mean 
concentrations of fumonisins obtained in this study. Research done by Pietri, et al. [11] showed that fumonisin 
concentrations were lower in the cleaned maize than the unprocessed kernels. Santini, et al. [16] also noted that 
cleaning, if done effectively, reduces fumonisins concentrations from the pericarp as well as from the damaged and 
broken grains by 50 %. Matumba, et al. [17] and Kimanya, et al. [18] also allude to the fact that sorting of maize 
prior to milling reduces contamination of maize by fumonisins since defective kernels are discarded. 
 

Table-1. Miller’s responses on mitigation measures to reduce fumonisin contamination in maize meal. 

Parameter Miller 1 Miller 2 Miller 3 Miller 4 Miller 5 

Vetting of grain for weevils ✓  ✓  ✓  ✓  ✓  

Monitoring moisture level ✓  ✓  ✓  ✓  ✓  

Treatment prior to storage with insecticides x ✓  x x ✓  

Covering of bags or silos x X ✓  ✓  ✓  

Cleaning of storehouse before storage ✓  ✓  ✓  ✓  ✓  

Removal of old grain before adding new grain ✓  ✓  ✓  ✓  ✓  

Use of pesticides during storage x ✓  ✓  ✓  ✓  

Sampling to monitor aflatoxin levels ✓  ✓  ✓  ✓  ✓  
Analysis for fumonisins before milling x X x x X 

Sorting of grain ✓  ✓  ✓  ✓  ✓  
Testing for fumonisins in the maize meal x X x x X 

             Note: √ -Being implemented       x- not being implemented. 

 
However, despite the cleaning and sorting processes, some fumonisins were detected. This could be attributed 

to the cleaning method (screening and sifting), which did not completely eliminate fumonisins but only served to 
reduce them. Nyangi [7] reported that the most noticeable sign of Fusarium infection in maize grown in the 
tropical areas is kernel rot. However, fumonisins are often detected in maize kernels even if in the absence of 
invisible signs of infection. 

All the millers interviewed stressed that they checked the moisture content of their grain upon receipt from the 
Grain Marketing Board (GMB). This mitigation measure helped in the prevention of moulds that cause fumonisin 
contamination. Bacon and Nelson [19] state that levels of kernel contamination by fumonisins under improper 
storage and the optimal growth condition for fumonisin-producing moulds are when moisture content of harvested 
maize is between 18-23 %. The monitoring of moisture levels within this range by these millers could be another 
reason for the low fumonisin levels detected in the maize meal analyzed in this study. 

Millers stored their grain in silos and this made them more susceptible to cross-contamination by fumonisins. 
The use of hermetic technology for grain storage could be an effective alternative method in the reduction of 
fumonisins since the bags or silos suffocate the insects and fungi, preventing contamination by fumonisins. Hove, et 
al. [4] noted that maize stored in polypropylene bags was less contaminated than un-bagged maize (mean 
FB1=263 µg/kg and 401 µg/kg respectively). Most of the millers interviewed indicated that in the silos, tobacco 
weevil was the most challenging. Weevils feed upon the kernels and at the same time spread the infection to other 
healthy kernels. In spite of vetting the grain for weevils upon its reception from the GMB, the weevils could 
mature in the grains stored in the silos, leading to contamination. Miller 1 indicated that they did not apply any 
insecticides during storage of the grain. This could be the reason for the highest level of fumonisin contamination 
compared to other millers. Other 4 millers were applying Phosphin gas tablets at a rate of 10 tablets per silo so as 
to kill the weevils in order to reduce contamination by fumonisins. This data shows that fumonisin control was not 
intentional, rather indirect through direct practices destined to assure the control of food safety and quality. 
 

3.2. Fumonisin Levels in Maize Meal 
Analysis was done on the types of maize meal from different millers to determine fumonisin levels. There was a 

significant difference among the 5 millers in the concentration of fumonisins in the maize meal.  There was also a 
significant difference between Fumonisin B1 and Fumonisin B2 levels in the 4 types of maize meal see Table 2. 
Again, a difference existed in the fumonisin concentration among the 4 types of maize meal (Roller meal, Super 
refined, Super refined with maize bran and Super refined with wheat bran). 

From the 72 samples analysed from the marketed maize meal produced by the large millers, all maize meal 
samples (roller meal, super refined, maize meal with wheat bran and maize meal with maize bran) had a fumonisin 
B1 level below the maximum tolerable limit (MTL) of 1 000µg/kg [20] see Table 2. Of the samples analysed for 
FB2 56.9 % had non-detectable levels. Although half the samples of super refined maize meal had concentrations 
below the detection limit, all maize meal samples with wheat bran added did not present detectable concentrations 
of fumonisin B2. There was much variability in FB2 levels of super refined and this could be attributed to the low 
sample size.  

Results from this study also showed mean fumonisin levels in the maize meal samples ranging from 61.64 
µg/kg to 265.79 µg/kg for FB1 and 0.00µg/kg to 76.93 µg/kg for FB2 Table 2.  All analysed samples had FB1 but 
only 43.1 % were contaminated by FB2. The lower concentrations of fumonisins observed, compared to other 
studies [3, 4, 21] could reflect the effectiveness of the measures taken by millers to indirectly assure the control of 
safety and quality of foods. 



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A research conducted by Doko, et al. [21] on Zimbabwean maize meal showed that 83 % of the analysed 
samples had fumonisin B1, B2 and B3   ranging between 55 µg/kg and 2 735 µg/kg.  Murashiki, et al. [3] recorded 
fumonisin concentrations ranging between 10.43 µg/kg and 606.64 µg/kg in maize meal samples from Shamva and 
Makoni Districts (P<0.05). These researchers analysed samples from small-holder farmers who took no 
precautionary measures against fumonisin contamination in the grains as large millers do, thus the high fumonisin 
levels detected.  

Fumonisin B1 and B2 mean concentrations were significantly higher in maize meal with maize bran than other 
maize meal types (mean =265.79 µg/kg). Roller meal had fumonisin mean concentrations which were slightly 
lower than those found in the maize meal with maize bran but higher than in super refined maize meal Table 2. 
This is because the bran is the most colonized by the Fusarium spp., followed by the germ fraction.  These results 
are comparable to Pietri, et al. [11], Brera, et al. [22] and Vanara, et al. [23] who reported that when the corn is 
milled, fumonisins are in elevated concentrations in the bran, followed by the germ fraction. Broggi and others 
carried out a study in a commercial dry-mill in Argentina and found a three-fold increase in fumonisin 
contamination in the germ and bran fractions than in the whole corn [7]. 

Roller meal samples had fumonisin levels higher than super-refined maize meal samples because some pericarp 
and germ fragments probably found their way into the course meal during dry- milling [24]. Even though there 
was no bran or germ added to the super-refined maize meal, some fumonisins (80.49 µg/kg), were recovered from 
the samples. The main cause of contamination could be due to the floury endosperm that surrounds the germ where 
a higher formation of fumonisins is possible. In support of this, Vanara, et al. [2] noted that the presence of 
amylopectin in the endosperm during kernel development instigates FB1 biogenesis. A study by Gwirtz and 
Garcia-Casal [25] on processing of maize flour and corn meal products also showed a remarkable lowering of 
fumonisin concentrations in the endosperm during dry milling. 

Levels of fumonisins obtained in maize meal where wheat bran was added to super refined were very low. At 5 
% significance level, there was no difference between super -refined maize meal and super refined maize meal with 
wheat added Table 2. This indicates that wheat was not a source of contamination by Fusarium compared to maize. 
Streit, et al. [26] state that fumonisin contamination commonly occurs in maize and maize products. 

However, although the results show that fumonisin concentration in the types of maize meal are within the 
maximum tolerable limit (MTL) of 1000 µg/kg by EU standard [12, 14] there is need for constant monitoring of 
fumonisin levels, especially in the maize meal with maize bran added and in the roller meal. 

Fumonisin B1 was found to be more abundant in the maize meal samples than fumonisin B2 Table 2. At a least 
significance difference of 5 %, the results from this research showed that there was a significant difference in the 
contamination of maize meal by the two types of fumonisins. Fumonisin B2 was not detected in maize meal samples, 
such as maize meal with wheat bran added and some super refined maize meal yet FB1 was detected in the same 
samples at 2.5 µg/kg detection limit. This also confirmed that Fumonisin B1 is the dominant type that 
contaminates Zimbabwean maize. This is in line with the observations by Marasas, et al. [27] and Rheeder, et al. 
[28] who noted that FBI pre-dominates and contributes 70-80 % of all fumonisins whereas FB2 constitutes 15-25 
% in maize grains. The differences in quantity between FB1 and FB2 could be because moulds produce higher 
quantities of the former. 
 

Table-2. Means of fumonisin concentration (µg/kg) for the different products from all millers combined. 

Fumonisin type Maize meal with 
maize bran 

Roller meal Super refined Maize meal with 
wheat bran 

FB1 265.79±22.22a 229.85±10.28b 80.49±10.28c 61.45±22.22c 

FB2 76.93±31.43c 32.83±12.15d 13.72±14.57d 0.0e 

Note: Means in the same row and column with different superscripts are different at 5 % significance level. Means with the same superscripts are 
the same at 5 % significance level. 

 
Analysis was done to assess fumonisin mean concentration in the types of maize meal produced by the different 

millers. Miller 1 had the highest mean fumonisin B1 concentration of 336.40 µg/kg Table 3.  The high levels in 
samples from Miller 1, compared to other millers, may be attributed to the fact that they were not treating their 
maize grains prior to storage and as a result, weevils could have probably attacked the grains whilst in silos and 
caused further contamination by fumonisins. Again, they did not cover the silos so it was easier for the insects to 
spread around and cause further contamination in, otherwise healthy, grains. Hove, et al. [4] also noted that the 
damage caused by pests contributes a lot to mycotoxin contamination of the maize grains. That is why it is of 
paramount importance to apply chemicals that protect the grain from damage. 

Miller 2 recorded the second highest mean levels of Fumonisin B1 (158.39 µg/kg) because it was the only 
interviewed Milling Company that manufactures maize meal with maize bran added to it. As has been mentioned 
earlier on, the bran fraction contains the highest fumonisin levels in maize grains. Furthermore, Miller 2 was not 
covering the silos so this may have caused cross- contamination of grain by weevils. At 5 % level of significance, 
there was no outstanding difference in fumonisin B1 mean concentration among millers 3, 4 and 5. They all 
recorded the low mean concentration.  Miller 2 showed a marked difference from all other miller as it contained 
high levels of fumonisin B2 (81.87 µg/kg). This could also be attributed to the fact that they produced maize meal 
with maize bran, which normally contains a significant amount of fumonisins. 

 
Table-3. Overall fumonisin mean concentration (µg/kg) for different millers for all types of maize meal combined. 

Fumonisin type Miller 1 Miller 2 Miller 3 Miller 4 Miller 5 

FB1 336.40±15.7a 158.39±13.8b 75.62±15.7c 94.96±15.8c 122.40±15.7 c 
FB2 10.05±18.6d 81.87±19.5ce 3.1419.1d 25.34±31.4d 19.60±19.1d 

Note: Means in the same row and column with different superscripts are different at 5% significance level. Means with the same superscripts are 
the same at 5 % significance level. 

 
 
 



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3.3. Estimate of the Average Probable Daily Intake (APDI) for Risk Assessment 
The magnitude of fumonisin contamination obtained in the present study was below the tolerable regulatory 

level of 1000 µg/kg which was set by the European Commission [20]. However, the Joint FAO/WHO expert 
committee on food additives (JECFA) set the health-based guidance value for FB1, FB2 and FB3 separately or 
combined at 2 µg/kg body weight/day [29]. In this study, risk assessment was done on the four types of maize 
meal to establish levels to which maize meal consumers are exposed to fumonisins daily.  

This study showed the Average Probable Daily Intake (APDI) of fumonisins by consumers Table 4. The values 
for maize meal with maize bran added and roller meal were above the set value of 2 µg/kg body weight/day. It is 
an indication that consumers of these types of maize meal with maize bran in Harare, Zimbabwe, are at greater risk 
of vulnerability due to the detrimental accumulative levels of fumonisins unlike consumers of super refined maize 
meal and maize meal with wheat bran added. Moreover, low level chronic intake of fumonisins in the maize and 
maize products can be more devastating than one-time high level intake A study carried out by Williams, et al. 
[30] reported that 4. 5 billion maize consumers in the developing countries are exposed to chronic toxicity.  

The study conducted by Murashiki, et al. [3] showed that populations in Shamva and Makoni Districts, 
Zimbabwe, had a Probable Daily Intake of 5.76-8.09 µg/kg body weight/day. These figures are slightly higher 
than the values calculated in this study, most probably due to the mitigation measures taken by the registered 
millers and the type of milling done to reduce fumonisin contamination in the maize meal unlike with unregistered 
millers used by Murashiki, et al. [3].  Further, analysis done by Hove, et al. [4] showed a Maximum Probable 
Daily Intake of 5.40 µg/kg body weight/day for children between 5-9 years, 4.40 µg/kg body weight/day for 
adolescents and 2.30 µg/kg body weight/day for adults in Zimbabwe. High fumonisin intakes (141.97 µg/kg body 
weight/day) have also been reported in Tanzania by Kimanya, et al. [18]. 

Other studies in the more economically developed countries, such as Spain and Brazil, have indicated fumonisin 
levels as low as 0.1 µg/kg body weight/day and 0.063 µg/kg body weight/day respectively [31]. These low values 
are perhaps due to the advanced and effective mitigation measure taken by these countries to mitigate fumonisin 
contamination in foods.  This is coupled to the low intake of maize–based foods [31] unlike in Zimbabwe where the 
staple diet is primarily maize-based. On grounds of the high Average Probable Daily Intake of fumonisins detected 
in some types of maize meal being sold in Harare markets, it is recommended to adopt some measures to mitigate 
the deleterious effects of fumonisin consumption. These mitigation practices include; sorting and cleaning of grain 
to remove broken and moldy kernels, application of grain-protection chemicals to kill weevils and monitoring of 
moisture levels to reduce contamination of grain by fumonisins [29].    
 

Table-4. Total mean fumonisin concentrations (FB1 + FB2) and probable intakes of marketed maize meal in Harare, Zimbabwe. 

Type of maize meal Total mean fumonisin 
concentration (µg/kg) 

Average Probable Daily Intake 
(µg/kg bw/day) 

Maize meal with maize bran added 342.72 4.57 
Roller meal 262.68 3.50 
Super refined 94.21 1.26 
Maize meal with wheat bran added 61.45 0.82 

        

4. Conclusion  
The levels of fumonisins in all the maize meal analyzed in this study were below the maximum tolerable limits 

of 1 000 µg/kg set by the European Union. However, the APDI of fumonisins estimated for maize meal with maize 
bran added and roller meal were above the provisional APDI set by WHO. Maize meal with maize bran added and 
Roller meal showed high contamination levels probably because they contained the bran and some germ that are 
highly contaminated by fumonisins. The high frequency of fumonisins consumed daily in both types of maize meal 
pose some health risks to consumers. There is need for setting up measures to check the quality of maize-based 
foods in order to alleviate the dangers of developing esophageal cancer and other probable health complications 
that are a result of fumonisin contamination. 

Results from this study also suggested that some of the practices that are being taken by the millers are 
effective at reducing fumonisin contamination in the maize meal. The milling process itself, which includes 
dehulling and de-germination of maize kernels, seems to dilute and re- distribute fumonisins into fractions that 
mostly become animal feed. It is of paramount importance to undertake further research on small- scale millers that 
will assist them to meet international quality standards and adopt those practices that minimize risks to fumonisin 
contamination in the maize meal they produce. 
 

References 
[1] S. Siyuan, L. Tong, and H. L. Rui, "Corn phytochemicals and their health benefits," Journal of Food Science and Human Wellness, vol. 

3, pp. 185-195, 2018. 
[2] F. Vanara, V. Scarpino, and M. Blandino, "Fumonisin distribution in maize dry-milling products and by-products: Impact of two 

industrial degermination systems," Toxins, vol. 10, p. 357, 2018. Available at: https://doi.org/10.3390/toxins10090357. 
[3] T. C. Murashiki, C. Chidewe, M. A. Benhura, D. T. Maringe, M. P. Dembedza, L. R. Manema, B. M. Mvumi, and L. K. Nyanga, 

"Levels and daily intake estimates of aflatoxin B1 and fumonisin B1 in maize consumed by rural households in Shamva and Makoni 
districts of Zimbabwe," Food Control, vol. 72, pp. 105-109, 2017. Available at: https://doi.org/10.1016/j.foodcont.2016.07.040. 

[4] M. Hove, M. De Boevre, C. Lachat, L. Jacxsens, L. Nyanga, and S. De Saeger, "Occurrence and risk assessment of mycotoxins in 
subsistence farmed maize from Zimbabwe," Food Control, vol. 69, pp. 36-44, 2016. Available at: 
https://doi.org/10.1016/j.foodcont.2016.04.038. 

[5] P. G. Thiel, W. F. Marasas, E. W. Sydenham, G. S. Shephard, and W. C. Gelderblom, "The implications of naturally occurring 
levels of fumonisins in corn for human and animal health," Mycopathologia, vol. 117, pp. 3-9, 1992. Available at: 
https://doi.org/10.1007/bf00497272. 

[6] M. E. Zain, "Impact of mycotoxins on humans and animals," Journal of Saudi Chemical Society, vol. 15, pp. 129-144, 2011. Available 
at: https://doi.org/10.1016/j.jscs.2010.06.006. 

[7] C. Nyangi, "Aflatoxin and fumonisin contamination of maize and beans along the food and feed value chain in Babati District, 
Tanzania," MSc Thesis. Sokoine University of Agriculture, Morogoro, Tanzania, 2014. 

[8] S. Marín Sillué, A. J. Ramos Girona, G. Cano Sancho, and V. Sanchís Almenar, "Mycotoxins: Occurrence, toxicology, and exposure 
assessment," Food and Chemical Toxicology, vol. 60, pp. 218-237, 2013. Available at: https://doi.org/10.1016/j.fct.2013.07.047. 



Agriculture And Food Sciences Research, 2020, 7(1): 58-64 

64 
© 2020 by the authors; licensee Asian Online Journal Publishing Group 

 

 

[9] L. B. Bullerman and A. Bianchini, "Stability of mycotoxins during food processing," International Journal of Food Microbiology, vol. 
119, pp. 140-146, 2007. Available at: https://doi.org/10.1016/j.ijfoodmicro.2007.07.035. 

[10] International Agency for Research on Cancer (IARC), Some traditional herbal medicines, some mycotoxins, naphthalene, and styrene. 
Monographs on the evaluation of the carcinogenic risk of chemicals to humans vol. 82. Lyon, France: IARC Press, 2002. 

[11] A. Pietri, M. Zanetti, and T. Bertuzzi, "Distribution of aflatoxins and fumonisins in dry-milled maize fractions," Food Additives & 
Contaminants: Part A, vol. 26, pp. 372-380, 2009. Available at: https://doi.org/10.1080/02652030802441513. 

[12] N. Nleya, M. C. Adetunji, and M. Mwanza, "Current status of mycotoxin contamination of food commodities in Zimbabwe," Toxins, 
vol. 10, p. 89, 2018. Available at: https://doi.org/10.3390/toxins10050089. 

[13] C. Li, Y.-L. Wu, T. Yang, and W.-G. Huang-Fu, "Rapid determination of fumonisins B1 and B2 in corn by liquid chromatography–
tandem mass spectrometry with ultrasonic extraction," Journal of Chromatographic Science, vol. 50, pp. 57-63, 2012. Available at: 
https://doi.org/10.1093/chromsci/bmr009. 

[14] D. Mwalwayo and B. Thole, "Prevalence of aflatoxin and fumonisins (B1+ B2) in maize consumed in rural Malawi," Toxicology 
Reports, vol. 3, pp. 173–179, 2016. Available at: https://doi.org/10.1016/j.toxrep.2016.01.010. 

[15] P. Martos, W. Thompson, and G. Diaz, "Multiresidue mycotoxin analysis in wheat, barley, oats, rye and maize grain by high-
performance liquid chromatography-tandem mass spectrometry," World Mycotoxin Journal, vol. 3, pp. 205-223, 2010. Available at: 
https://doi.org/10.3920/wmj2010.1212. 

[16] A. Santini, A. Raiola, G. Meca, and A. Ritieni, "Aflatoxins, ochratoxins, trichotecenes, patulin, fumonisins and beauvericin in 
finished products for human consumption," Journal of Clinical Toxicology, vol. 5, pp. 2-11, 2015. Available at: 
https://doi.org/10.4172/2161-0495.1000265. 

[17] L. Matumba, C. Van Poucke, E. Njumbe Ediage, B. Jacobs, and S. De Saeger, "Effectiveness of hand sorting, flotation/washing, 
dehulling and combinations thereof on the decontamination of mycotoxin-contaminated white maize," Food Additives & 
Contaminants: Part A, vol. 32, pp. 960-969, 2015. Available at: https://doi.org/10.1080/19440049.2015.1029535. 

[18] M. E. Kimanya, B. De Meulenaer, B. Tiisekwa, M. Ndomondo-Sigonda, F. Devlieghere, J. Van Camp, and P. Kolsteren, "Co-
occurrence of fumonisins with aflatoxins in home-stored maize for human consumption in rural villages of Tanzania," Food 
additives and contaminants, vol. 25, pp. 1353-1364, 2008. 

[19] C. W. Bacon and P. E. Nelson, "Fumonisin production in corn by toxigenic strains of Fusarium moniliforme and Fusarium 
proliferatum," Journal of Food Protection, vol. 57, pp. 514-521, 1994. Available at: https://doi.org/10.4315/0362-028x-57.6.514. 

[20] European Commission, "Commission regulation (EC) No 1126/2007 of 26 September 2007 amending regulation (EC) No 
1881/2006: Setting maximum levels for certain contaminants in foodstuffs as regards Fusarium toxins in maize and maize 
products," Journal of European Union Legislation, vol. 254, pp. 14–17, 2007. 

[21] M. B. Doko, C. Canet, N. Brown, E. W. Sydenham, S. Mpuchane, and B. A. Siame, "Natural co-occurrence of fumonisins and 
zearalenone in cereals and cereal-based foods from Eastern and Southern Africa," Journal of Agricultural and Food Chemistry, vol. 44, 
pp. 3240-3243, 1996. Available at: https://doi.org/10.1021/jf960257+. 

[22] C. Brera, F. Debegnach, S. Grossi, and M. Miraglia, "Effect of industrial processing on the distribution of fumonisin B1 in dry 
milling corn fractions," Journal of Food Protection, vol. 67, pp. 1261-1266, 2004. Available at: https://doi.org/10.4315/0362-028x-
67.6.1261. 

[23] F. Vanara, A. Reyneri, and M. Blandino, "Fate of fumonisin B1 in the processing of whole maize kernels during dry-milling," Food 
Control, vol. 20, pp. 235-238, 2009. Available at: https://doi.org/10.1016/j.foodcont.2008.05.014. 

[24] M. Castells, S. Marín, V. Sanchis, and A. J. Ramos, "Distribution of fumonisins and aflatoxins in corn fractions during industrial 
cornflake processing," International Journal of Food Microbiology, vol. 123, pp. 81-87, 2008. Available at: 
https://doi.org/10.1016/j.ijfoodmicro.2007.12.001. 

[25] J. A. Gwirtz and M. N. Garcia-Casal, "Processing maize flour and corn meal food products," Annals of the New York Academy of 
Sciences, vol. 1312, pp. 66-75, 2014. Available at: https://doi.org/10.1111/nyas.12299. 

[26] E. Streit, G. Schatzmayr, P. Tassis, E. Tzika, D. Marin, I. Taranu, C. Tabuc, A. Nicolau, I. Aprodu, and O. Puel, "Current situation 
of mycotoxin contamination and co-occurrence in animal feed—Focus on Europe," Toxins, vol. 4, pp. 788-809, 2012. Available at: 
https://doi.org/10.3390/toxins4100788. 

[27] W. Marasas, W. Gelderblom, G. S. Shephard, and H. Vismer, Mycotoxins: A global problem. In: Mycotoxins: Detection methods, 
management, public health and agricultural trade. (Edited by Leslie, J.F. Bandyopadhyay, R. and Visconti, A.). Townbridge, UK: Cromwell 
Press, 2008. 

[28] J. P. Rheeder, W. F. Marasas, and H. F. Vismer, "Production of fumonisin analogs by Fusarium species," Journal of Applied 
Environmental Microbiology, vol. 68, pp. 2101-2105, 2002. Available at: https://doi.org/10.1128/aem.68.5.2101-2105.2002. 

[29] World Health Organization, "Food and safety digest. Department of food safety and zooness. Retrieved from: 
https://www.who.int/foodsafety/foodsafetydigest/en/," 2018. 

[30] J. H. Williams, T. D. Phillips, P. E. Jolly, J. K. Stiles, C. M. Jolly, and D. Aggarwal, "Human aflatoxicosis in developing countries: 
A review of toxicology, exposure, potential health consequences, and interventions," The American Journal of Clinical Nutrition, vol. 
80, pp. 1106-1h122, 2004. Available at: https://doi.org/10.1093/ajcn/80.5.1106. 

[31] G. Cano-Sancho, A. J. Ramos, S. Marín, and V. Sanchis, "Occurrence of fumonisins in Catalonia (Spain) and an exposure assessment 
of specific population groups," Food Additives & Contaminants: Part A, vol. 29, pp. 799-808, 2012. Available at: 
https://doi.org/10.1080/19440049.2011.644813. 

 

 
 

 

 

 

 

  

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