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 American Journal of  
Food Science and Technology (AJFST)

Molds and Mycotoxins in Food Value Chain: A Challenge to Food and Nutrition Security 
Adeoye B. A.1*, Fadesire A. K.2,  Nyam P. N.4, Olukotun G. B.1, Labbo Z.1, Ahmadu J. H.1, Egbulefu C. S.1

Shanu M. A.3,  Busari A. K.1, Mbochi C. A.3

Volume 2 Issue 2, Year 2023
ISSN: 2834-0086 (Online)

DOI: https://doi.org/10.54536/ajfst.v2i2.1932
https://journals.e-palli.com/home/index.php/ajfst

Article Information ABSTRACT

Received: July 20, 2023

Accepted: August 17, 2023

Published: September 07, 2023

Due to postharvest losses on fresh produce, most farmers apply simple and affordable open 
sun-drying in-between harvest and the final consumers but this method causes the growth 
of  mold and fungi in processed food. Hence, the objective of  this study was to isolate and 
characterize molds associated with the drying of  plantain chips, and post-drying handling of  
catfish and cassava peels using standard laboratory procedures. One gram (1gm) of  respec-
tive samples of  plantain chips, dried fish, and cassava peel was taken and crushed in a mortar, 
1g of  each was serially diluted up 10-6 fold, and 0.1mL of  each was pour-plated in potato 
dextrose agar modified with chloramphenicol and incubated for 72 hours at 280C. Thereaf-
ter, discrete colonies were counted and characterized using standard laboratory procedures.
A total of  eight fungal isolates were identified which were Aspergillus flavus, Rhizopus sp., 
Aspergillus niger, Fusarium sp., Penicillium digitatum, Aspergillus fumigatus, Mucor sp., Neurospora 
sp. The mean fungal counts of  cassava peels revealed that the samples recorded the highest 
mean fungal counts which were by Mucor sp. (24.1x106 Cfu/g) while Catfish had the lowest 
overall mean counts (3.2x106 Cfu/g). But Aspergillus niger had the lowest counts of  (2.7x106 
Cfu/g) in plantain chips.  The total mean fungal count at ratio: catfish (31.4), plantain chips 
(37.6), and cassava peel (111). In conclusion, several findings from this work showed that 
samples dried under the sun in the studied area were contaminated with mycotoxin-produc-
ing microbes that could lead to their early decay, deterioration and loss of  nutrients.

Keywords

Fungi, Consumer, Mycotoxin, 
Molds, Food Value Chain, 
Nutrition Security

1 National Biotechnology Development Agency, Musa Yaradua Express Way, Lugbe, FCT, Abuja, Nigeria
2 Department of  Nutrition and Dietetics, SIIHST Makarfi Campus Kaduna State University, Nigeria
3 Department of  Nutrition and Dietetics, School of  Health, Makarfi, Kaduna State, Nigeria
4 Department of  Social Sciences, SIIHST Markarfi Campus Kaduna State University, Nigeria
* Corresponding author’s e-mail: benadeoye98@gmail.com

INTRODUCTION
In developing countries like Nigeria, farming activity 
is increasing due to the daring need to feed the ever-
growing population. Several of  these population lives in 
urban areas requiring a lot of  food and material supplies 
for themselves and their livestock.  Fish is one of  the 
most nutritious food sources for humans due to their 
high protein content. As such, they are very suitable for 
microorganisms as a growth medium (Lina et al., 2021). 
The growth of  these organisms coupled with lipid 
degradation often leads to the spoilage of  this important 
product. High environmental temperature and moisture 
often create conducive conditions for this deterioration 
which eventually reduce the quality of  fish and its keeping 
time and shelf  life (Sean T. Hammond et al., 2015). 
Plantain chips are known to be an attractive nourishing 
essential food in certain areas of  African countries slated 
due to their nutritional content. The immature, plantain 
is developed into a powdery form/state using the usual 
local sun-drying procedure and method to process, in 
other reduce/maintain the moisture content to extend its 
shelf  life and retain the quality (Marina et al., 2019).
Microbial population growth rates depend on 
environmental conditions, Temperature is key to 
metabolic rates/action and growth of  food-spoiling 
microbes (Sean T. Hammond et al., 2015).
The continued growth of  mold and fungi in processed 

food produces mycotoxins in its food resulting in spoilage 
via spores that germinate and form visible mycelium 
before the end of  processing (P. Battalini, 2008). 
Mycotoxins are poisonous toxic secondary metabolites 
produced by fungi naturally; they are of  low molecular 
weight not contagious or infectious but can be found 
on plant/food products generally, they are capable of  
causing acute/intoxication and spoilage (Mohammed S. 
S. D. et al., 2013).
In this part of  the world, farm produces are usually in 
abundance during the rainy season thereby making 
foods surplus, leading to either wastage or farmers being 
forced to sell at cheap prices leading to serious loss of  
input capital, profit, and effort. Slow drying especially 
during the high-humid period results in mold build-
up by different types of  microflora and subsequent 
associated health risks. Controlling moisture can prevent 
fungi growth. Therefore, this study aimed to assess fungi 
associated with dried catfish, plantain chips, and cassava 
peels during open sun-drying and storage, as well as the 
health risks from mycotoxin-producing molds.

MATERIALS AND METHODS
Study Area
The study was carried out at the microbiology laboratory 
of  the Food and Industrial Biotechnology Department 
of  the National Biotechnology Development Agency, 



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Am. J. Food. Sci. Technol. 2(2) 18-22, 2023

Lugbe, Federal Capital Territory, Nigeria. I tried, but see 
below for best google map location, thanks

food (Pitt, J.I., Hocking, A.D., 2009). The fungi isolated 
were identified microscopically using simple staining 
techniques where two to three (2-3) drops of  Lactophenol 
Cotton Blue stain were added to a cut portion of  the 
growing fungi under a cover slip and observed with oil 
immersion under the microscope. Biochemical tests 
were carried out according to the methods described by 
Harrigan and McCance (1976) as well as Seeley and Van 
Demark (1972) on morphology, motility, spore staining, 
catalase, coagulase production, starch hydrolysis, and 
sugar fermentation. (Onyeze et al., 2019).
Personal Protective Equipment (PPE) such as respirators/
nose masks, goggles, gloves, and lab coats was used 
considering the number one laboratory rule, which is 
safety first so that researchers were well protected.  Also 
putting into consideration spore from the fungal.  The 
usage of  Laminar Flow hood during pour-plating. The 
fungi were killed via proper decontamination Burgener, 
J. (2006) before discarding to avoid exposing the 
environment to hazardous and pathogenic organisms.

RESULTS 
Biochemical Test

Figure 1: New view of  study area using google map

Sample Collection 
A total of  ten (10) African catfish were randomly 
obtained from River Niger bank, Marine Road in Lokoja 
where drying of  fish was done by some local processors. 
Five (5) plantain chips undergoing open sun-drying were 
also randomly collected and were carefully packed into 
polythene bags separately and labelled. Open sun-drying 
cassava peels were obtained from Garri Processing Centre 
at Lokongoma Phase II. All materials were transported to 
the microbiology laboratory for mycological analysis.

Isolation and Characterization of  Fungi
One gram (1g) of  the respective sample was measured 
and mashed using a mortar and a pestle and was added 
to nine milliliters (9mL) of  pre-sterilized sterile peptone 
water and, serially diluted up to 10-6 fold. Afterwards, 
1mL from 10-2, 10-4, and 10-6 suspensions of  the 
samples (Catfish, Plantain chips, and cassava peels) were 
pour-plated using freshly prepared potato Dextrose 
Agar previously modified by adding Chloramphenicol 
antibiotics to suppress bacteria growth. The mixture was 
then gently swirled to mix and allowed to gel after which 
the plates were incubated at 280C for three to five (3-5) 
days. After the incubation period, the discrete colonies 
that emerged were counted, characterized, and purified 
by sub-culturing several times and then the pure cultures 
were maintained on the modified potato dextrose agar 
slants as stock until further use, media suitable for the 
enumeration, isolation, and identification of  fungi from 

Test Results
Spore Staining Sporangia

Conidiospores
Sporangiospores

Sugar Fermentation Glucose (+) 
Maltose (+)
Galatose (+)

Hydrolysis (+)
Spore staining Fungi spore 

Hyphae
Fruiting structure stains blue 
while the background stains 
blue

Catalase Most are a catalyst (-ve)
Motility non-motile
Morphology Generally the hyphae grew 

and form a network on known 
mycelia

Starch hydrolysis (+)

Enumeration of  Fungi Colonies that developed after 
incubation were subjected to counting. The total fungal 
counts were expressed as spore/g.

Fungi Load of  The Selected Food/Feed Samples 

Table 1: The Occurrence of  Fungal Isolates Associated with the Samples
Fungal Isolate                                       Fungal Counts on Sample (x106 Cfu/g)                                        

Catfish                       Plantain chips Cassava peels
Aspergillus flavus                                    4.2 5.3 -
Rhizopus sp.                                            - 4.9 23.2



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Am. J. Food. Sci. Technol. 2(2) 18-22, 2023

Figure 2: Relative Occurrence of  Fungi on the Samples

A close observation of  Table 1 for total fungal counts 
and prevalence shows that cassava peels had the highest. 
(Fig. 2) shows relative occurrence in samples comparison.

DISCUSSION
From the study shown in Table 1, the mean fungal counts 
of  cassava peels revealed that the samples recorded the 
highest mean fungal counts which were by Mucor sp. 
(24.1x106 Cfu/g) while Catfish had the lowest overall mean 
counts overall but Aspergillus niger had the lowest counts 
of  2.7x106 Cfu/g in plantain chips. A total of  eight fungal 
isolates were identified which Aspergillus flavus, Rhizopus sp., 
Aspergillus niger, Fusarium sp., Penicillium digitatum, Aspergillus 
fumigatus, Mucor sp., Neurospora sp. and  Aspergillus fumigatus 
was not found on Catfish and plantain chips. Most of  the 
organisms found in these samples are those commonly 
found in air and soil environments as should be expected 
and reported, Aspergillus niger is most commonly found 
in mesophilic environments such as decaying vegetation 
or soil and plant materials (Belli et al., 2004). In general 
terms, fungi grow and survive in optimal conditions most 
especially in humid environments. Hence, they require a 
certain moisture level which if  provided by foods during 
processing could lead to their growth and eventual 
spoilage (Essono et al., 2007). A close observation of  
Table 1 for fungal counts and prevalence shows that 
cassava peels had the total highest fungal count (Fig. I) 
and prevalence for Aspergillus niger when compared with 
other samples.  This revealed that all is not well with the 
food materials studied owing to the fungi quality present 
in the three products; Catfish, plantain chips, and cassava 
peels processed in the area selected. The isolation of  
pathogenic and spoilage fungi such as Aspergillus flavus 
in this work raises public health concerns about safety 
in consuming the products because of  the mycotoxins 
they might contain. The presence of  the identified fungi 

in the products is attributed mainly to the high moisture 
contents of  the atmosphere followed by poor handling 
by the processors. The mean fungal counts of  cassava 
peels revealed that the samples recorded the highest mean 
fungal counts which was by Mucor sp (24.1x106 Cfu/g) 
while Catfish had the lowest overall mean counts overall 
but Aspergillus niger  had the lowest counts of  2.7x106 
Cfu/g in plantain chips.  This result exceeded the range 
of  specified microbiological limits recommended for 
products meant for human consumption (Roberts et al., 
1996). 
The results of  this study were in no contradiction but 
similar to previous studies, such that - The observation 
might be due to the fact that Aspergillus niger is common 
in the soils from where cassava roots were drugged out 
(Awuah and Akrasi, 2007). Also, cassava tubers are usually 
not washed thoroughly before being peeled. This might 
be the reason for the high incidence of  the organism 
on the peel. This account agrees with several reports 
such as those of  (Arotupin and Akinyosoye, 2006) in 
their work on the Microbiological and Physicochemical 
Characteristics of  Cassava Cultivated Soils. In a similar 
observation, Aspergillus niger was the dominant fungal 
on plantain chips (6.2x106 Cfu/g). Conversely, however, 
Fusarium sp. recorded the highest occurrence of  Catfish 
(6.2x106). 
The obtained result might be attributed to poor post-
drying handling of  the fish samples and supported by the 
fact that fungi have the ability to grow and survive in a 
wide range of  temperatures such as 6-47°C and pH range 
of  1.4-9.8 (Morya and Yadav, 2009). 
(Ajay et al., 2011) also reported Aspergillus niger as one of  
the commonest microorganisms associated with smoked 
fish.
It was also reported that Mucor sp. thrives in soil, plants, 
manure, decaying fruits, and vegetables; hence, they 
are regarded as a common contaminant of  stored and 
processed foods in the kitchen (Adebayo-Tayo et al., 
2008). The incidence of  Mucor species causing disease in 
man has been reported because of  their ability to grow 
and thrive at high temperatures (thermo-tolerant status). 
Table1 shows that Mucor sp. was present in all the samples. 
This could be attributed to the storage conditions of  the 
food and feed materials by the fish handlers especially the 
facilities used for their processing as well as the exposure to 
the environment because all the fungi produce spores that 
make them ubiquitous in nature (Krijgsheld et al., 2013). 
Generally speaking, the growth and high occurrence of  
fungi populations and mycotoxins in dried fish products 

Aspergillus niger                                    4.0                                                  2.7 23.6                              
Fusarium sp.                                           6.2                        3.8 2.1
Penicillium digitatum                              4.3                        5.2 1.2
Aspergillus fumigatus                                - - 21.3
Mucor sp.                                                 3.2                         6.2 24.1
Neurospora sp                                          3.3 - 3.2
Total   31.4 37.6 111



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Am. J. Food. Sci. Technol. 2(2) 18-22, 2023

cause spoilage and pose a potential health threat to 
consumers as reported earlier by (Yijia Deng et al., 2021).
Several findings from this work showed that samples dried 
under the sun in the studied area were contaminated with 
mycotoxin-producing microbes that could cause their 
early decay, deterioration and loss of  nutrients, which 
pose a potential health threat to consumers
Awareness has been created with the result of  this 
research work that slows drying in humid environments 
aids molds and mycotoxins production that constitutes 
health and nutrition challenges, hence hindering food 
security. This research work is relevant in providing a 
solution to the challenge of  food and nutrition security by 
alerting food processors to the danger of  the slow drying 
process involved in the humid environment. 
Further implementation – This will be to conduct 
further research on different drying temperature range to 
ascertain the best drying temperature that can minimize 
the growth of  mycotoxin-producing microbes for 
each sample; catfish, cassava peel, and plantain chips 
respectively.

CONCLUSION
It was concluded that the foods and feed products 
processed in the Lokongoma,  market/centers in Lokoja, 
Kogi State Nigeria were contaminated with pathogenic 
and spoilage microbes that thrive due to the presence of  
high humidity via slow drying. The findings from this 
work show that smoked catfish dried under the sun in the 
studied area were contaminated with fungi that could lead 
to their deterioration and loss of  nutrients. Exposure of  
cassava peels to conditions that accelerate fungal growth 
poses a danger to the health of  animals since little or no 
processing is done afterwards.

RECOMMENDATION
Based on the findings it was recommended that: 

1. Drying of  human food materials/food stuff  be 
done using a hot air oven to prevent the growth and 
multiplication of  mycotoxin-producing microbes

2. Centralized food processing equipment be 
established in the hinterlands for the rural folks.

Conflict of  Interest
No conflict of  interest.

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