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Recent Submissions
Draft genome sequence of two Aspergillus aculeatus isolated from cashew nuts from coastal Kenya
(American Society for microbiology, 2024-09-16) Manase Onyango Aloo,1,2 Pauline Wambui Gachanja,1,2 Eugene Mwanza Muzami,1,2 Kyalo Katua,1,2 Dennis Wamalabe Mukhebi,1,2 Colletah Rhoda Musangi,1,2 Bicko Steve Juma,2,3 Wilton Mwema Mbinda1,2
Aspergillus aculeatus is a common saprophyte and ubiquitous fungus
belonging to section Nigri. They produce diverse secondary metabolites which are
important in biological processes and industrial applications. We present the draft
genome sequences of two A. aculeatus isolated from cashew nuts from coastal Kenya.
Aspergillus population diversity and its role in aflatoxin contamination of cashew nuts from coastal Kenya
(PLOS one, 2025-01-24) Colletah Rhoda Musangi1,2, Bicko Steve Juma2 , Dennis Wamalabe Mukhebi1,2, Everlyne Moraa Isoe1 , Cromwell Mwiti Kibiti3 , Wilton Mwema MbindaID1,2*
Cashew nuts are among the main cash crops in coastal Kenya, due in large part to their high
nutritional value. Unfortunately, they also make them highly susceptible to mold contamination, resulting in biodeterioration of the nutritional value and potential contamination with
toxic secondary metabolites, such as aflatoxins, that cause them to be rejected for sale at
the market. We determined the population diversity of the Aspergillus species and their role
in aflatoxin contamination in cashew nuts in selected coastal regions of Kenya. Fifty raw
cashew nut samples were collected from post-harvest storage facilities across three counties in Kenya’s coastal region and examined for moisture content and the presence of
Aspergillus fungi. About 63 presumptive isolates were recovered from the cashew nuts. ITS
and 28S rDNA regions were sequenced. The aflD, aflM and aflR genes were amplified to
identify the potentially aflatoxigenic from the Aspergillus isolates. The Aflatoxins’ presence
on the isolates was screened using UV and the ammonia vapour test on coconut milk agar
and validated using ELISA assay. A comparison of cashew moisture content between the
three counties sampled revealed a significant difference. Sixty-three isolates were recovered and identified to section based on morphological characters and their respective ITS
regions were used to obtain species identifications. Three sections from the genus were represented, Flavi and Nigri, and Terrei with isolates from the section Nigri having slightly
greater abundance (n = 35). The aflD, aflM and aflR genes were amplified for all isolates to
assess the presence of the aflatoxin biosynthesis pathway, indicating the potential for aflatoxin production. Less than half of the Aspergillus isolates (39.68%) contained the aflatoxin
pathway genes, while 22.22% isolates were aflatoxigenic, which included only the section
Flavi isolates. Section Flavi isolates identification was confirmed by calmodulin gene. The
presence of species from Aspergillus section Flavi and section Nigri indicate the potential
for aflatoxin or ochratoxin in the cashew nuts. The study established a foundation for future
investigations of the fungi and mycotoxins contaminating cashew nuts in Kenya, which
necessitates developing strategies to prevent infection by mycotoxigenic fungi, especially
during the storage and processing phases.
DArTseq-based silicoDArT and SNP markers reveal the genetic diversity and population structure of Kenyan cashew (Anacardium occidentale L.) landraces
(PLOS one, 2025-01-31) Dennis Wamalabe Mukhebi, Pauline Wambui Gachanja, Diana Jepkoech Karan, Brenda Muthoni Kamau , Pauline Wangeci King’ori , Bicko Steve Juma2,3 , Wilton Mwema Mbinda 1,2 *
Cashew (Anacardium occidentale L.) is an important tree grown worldwide for its edible fruits, nuts and other products of industrial applications. The ecologically sensitive
cashew-growing region in coastal Kenya is significantly affected by rising temperatures,
droughts, floods, and shifting rainfall patterns. These changes adversely impact cashew
growth by altering flowering patterns, increasing pests and diseases, and causing postharvest losses, which ultimately result in reduced yields and tree mortality. This is exacerbated by the long juvenile phase, high heterozygosity, lack of trait correlations, large
mature plant size, and inadequate genomic resources. For the first time, the Diversity
Array Technology (DArT) technology was employed to identify DArT (silicoDArT) and
single nucleotide polymorphisms (SNPs) markers for genomic understanding of cashew
in Kenya. Cashew leaf samples were collected in Kwale, Kilifi and Lamu counties along
coastal Kenya followed by DNA extraction. The reduced libraries were sequenced using
Hiseq 2500 Illumina sequencer, and the SNPs called using DarTsoft14. A total of 27,495
silicoDArT and 17,008 SNP markers were reported, of which 1340 silicoDArT and 824
SNP markers were used for analyses after screening, with >80% call rate, >95% reproducibility, polymorphism information content (PIC ≥ 0.25) and one ratio (>0.25). The
silicoDArT and SNP markers had mean PIC values ranging from 0.02–0.50 and 0.0–0.5,
with an allelic richness ranging from 1.992 to 1.994 for silicoDArT and 1.862 to 1.889 for
SNP markers. The observed heterozygosity and expected values ranged from 0.50–0.55
and 0.34–0.37, and 0.56–0.57 and 0.33 for both silicoDArT and SNP markers respectively.
Understanding cashew genomics through the application of SilicoDArT and SNP markers
is crucial for advancing cashew genomic breeding programs aimed at improving yield and
nut quality, and enhancing resistance or tolerance to biotic and abiotic stresses. Our study
presents an overview of the genetic diversity of cashew landraces in Kenya and demonstrates that DArT systems are a reliable tool for advancing genomic research in cashew
breeding
Camel milk products beyond yoghurt and fresh milk: challenges, processing and applications
(© Association of Food Scientists & Technologists (India) 2023, 2023-01-09) Philip K. Marete · Alfred M. Mariga· Guyo Huka · Levi Musalia · Eunice Marete · Julius M. Mathara · Joshua M. Arimi
Camel (Camelus dromedarius and (Camelus bactrianus) are commonly domesticated in the arid and
semi-arid regions because they are well adapted to live in
harsh climatic conditions. Camel milk is widely consumed
in these regions due to its high nutritional value and medicinal properties. It is rich in protein, minerals and vitamins.
Moreover, it possesses therapeutic properties such as antimicrobial, anti-oxidants, anti-viral and anti-cancer. Camel
milk can be processed into value added products with the
aim of extending shelf life and diversifying its usage. However, there are various challenges experienced in processing of camel milk products. This study aims at reviewing
published literature on camel milk products processing,
processing challenges, the available solutions and applications. To achieve these aims, literature search was carried
out using narrative methodology. Literature review provided
information concerning processing of camel milk products,
the challenges, how to overcome these processing challenges
and applications. From this review of literature on camel
milk products it can be concluded that it’s possible to process these products with some challenges but scientific and
technological solutions are available that are improving over
time.
Production and characterisation of camel milk yoghurt containing different types of stabilising agents
(Elsevier Ltd., 2022-11-15) Stephen Oselu a , Rebecca Ebere a , Guyo Huka b , Levi Musalia c , Eunice Marete d , Julius M. Mathara e , Florence Mwobobia a , Joshua M. Arimi a
As at 2020, Kenya was the best performing camel milk producer globally, with an annual production of 1.125
million tonnes. Despite the high production, about 50% of milk is wasted due to challenges affecting value
addition to products such as yoghurt. The production of camel milk yoghurt faces multiple challenges, such as
poor texture and weak structure, resulting in poor consumer acceptability. This study aimed to improve the
physicochemical properties of camel milk yoghurt by adding different stabilising agents and calcium chloride.
Yoghurt samples were processed using 3 L of camel milk, 6% sugar, 0.006% starter cultures, corn starch or
modified starch and calcium chloride. The stabilisers were added at 2, 2.5, and 3% and Calcium Chloride at
0.075%. The milk was pasteurised at 90 C for 30 min. Fermentation was performed for 6 h at 42 1 C, and
yoghurt was stored at 4 C. The total titratable acidity, pH and viscosity were monitored hourly during
fermentation and storage, while syneresis and water holding capacity were analysed at 1, 7, 14 and 21 days of
refrigerated storage. The sensory evaluation was done using the 9-point hedonic scale to rate yoghurt samples'
overall acceptability, colour, sweetness and thickness. The TTA of camel milk yoghurt increased with increasing
fermentation time (0–6 h) and storage time from 1 to 21 days. The pH decreased with increasing fermentation
time (0–6 h) and storage time from 1 to 21 days. The addition of stabilisers increased the viscosity of the yoghurt,
with 3% corn starch exhibiting the highest viscosity throughout the fermentation and storage time. Corn starch
had a higher effect on viscosity compared to modified starch. Calcium chloride further amplified the viscosity of
the yoghurt. The addition of stabilisers reduced syneresis by over 44% compared to bovine yoghurt. In this study,
the best results of viscosity, syneresis and sensory evaluation were observed when stabilising agents were added at
the rate of 2.5% modified starch and 0.075% Calcium chloride
