Food Safety(Aflatoxin-Studies)

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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.
Chia Oil Adulteration Detection Based on Spectroscopic Measurements
(MDPI, 2021-08-04) Monica Mburu, Clement Komu, Olivier Paquet-Durand, Bernd Hitzmann and Viktoria Zettel
Chia oil is a valuable source of omega-3-fatty acids and other nutritional components. However, it is expensive to produce and can therefore be easily adulterated with cheaper oils to improve the profit margins. Spectroscopic methods are becoming more and more common in food fraud detection. The aim of this study was to answer following questions: Is it possible to detect chia oil adulteration by spectroscopic analysis of the oils? Is it possible to identify the adulteration oil? Is it possible to determine the amount of adulteration? Two chia oils from local markets were adulterated with three common food oils, including sunflower, rapeseed and corn oil. Subsequently, six chia oils obtained from different sites in Kenya were adulterated with sunflower oil to check the results. Raman, NIR and fluorescence spectroscopy were applied for the analysis. It was possible to detect the amount of adulterated oils by spectroscopic analysis, with a minimum R2 of 0.95 for the used partial least square regression with a maximum RMSEPrange of 10%. The adulterations of chia oils by rapeseed, sunflower and corn oil were identified by classification with a median true positive rate of 90%. The training accuracies, sensitivity and specificity of the classifications were over 90%. Chia oil B was easier to detect. The adulterated samples were identified with a precision of 97%. All of the classification methods show good results, however SVM were the best. The identification of the adulteration oil was possible; less than 5% of the adulteration oils were difficult to detect. In summary, spectroscopic analysis of chia oils might be a useful tool to identify adulterations
Draft genome sequence of 16 Aspergillus flavus isolated from cashew nuts from coastal Kenya
(American society for microbiology, 2024-09-09) Pauline Wambui Gachanja1,2, Manase Aloo Onyango1,2, Colletah Rhoda Musangi1,2, Bicko Steve Juma2, Dennis Wamalabe Mukhebi1,2, Eugene Mwanza Muzami1,2, Kyalo Katua1,2, Wilton Mwema Mbinda
Aspergillus flavus is a soil-borne fungus known for its aflatoxin contamination of agricultural products. Here, we report the draft genome sequences of 16 predicted aflatoxin-producing A. flavus isolated from cashew nuts from coastal Kenya.
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.
Evaluation of the Mineral Composition of Chia (Salvia Hispanica L.) Seeds from Selected Areas in Kenya
(Canadian Center of Science and Education, 2023-03-16) Pauline W. Ikumi , Monica Mburu, Daniel Njoroge, Nicholas Gikonyo & Musingi Benjamin M
Chia (Salvia hispanica L.) seeds are gaining popularity among consumers and food processors, particularly in food fortification. Consequently, there has been an increased need to determine the mineral composition of chia seeds cultivated in different regions to ascertain their potential in various food applications. In this study, 20 chia seeds samples obtained from farmers practicing commercial farming of chia seeds in selected areas in Kenya during the two main chia seed planting seasons (April-August 2019) and (September-December 2019) were analyzed for their mineral content using Atomic Absorption Spectrophotometry (AAS). Values of sodium and potassium were determined using a Flame photometer using sodium chloride (NaCl) and potassium chloride (KCl) as the standards, while phosphorus was determined using the Vanodo-molybdate method. Chia seeds samples studied revealed the most predominant minerals as phosphorus (531 to 889 mg/100g), calcium (478 to 589 mg/100g), potassium (343 to 526 mg/100g) and, magnesium (322 to 440 mg/100g). The general linear model (GLM) used to determine the coefficient of variation on all chia seed growing sites showed that calcium, iron, and magnesium are the best-performing chia minerals in Kenya and hence should be the minerals of interest in food fortification using chia seeds.
Mould Characterization and Mycotoxin Quantification of Chia Seeds (Salvia hispanica L.) Grown in Kenya
(Canadian Center of Science and Education, 2019-10-30) Veronicah Njeri, Monica Mburu, & Kipkorir Koskei
Chia seeds are functional food that have been considered highly nutritious. They have high levels of polyunsaturated fatty acid content therefore counteract lifestyle disorder such as cardiovascular diseases. This study sought to determine the level of mould contamination in chia seeds; enumeration and characterization of the types of molds and quantification of mycotoxin level, for chia seeds grown and sold in Kenya. A complete randomized block design with triplicates was used in the study. Samples were collected at random from farmers and distributors in Nyeri, Nakuru, Busia and Trans Nzoia counties. Moulds species were isolated from PDA and MEA Medias and morphological characteristics was determined under X 40 magnification power. Mould counts were found to be between 1.33 X 103 cfu/ml to 2.67 X 103 cfu/ml. Mould characterization done by microscopic and macroscopic technique showed evidence of Rhizopus spp, Trichoderma spp and Fusarium spp. Amongst the three genera found, Rhizopus spp was the predominantly occurring mould. The percentage moisture content of chia seeds samples ranged from 6.49±1.26 and 9.16±0.43. Significant variations on moisture content (p< 0.05) were observed among chia samples from different farmers. Aflatoxin was not detected in all chia samples. It can therefore be concluded that the chia samples were not contaminated with aflatoxin although different species of mold were present. Farmers need to be trained on proper postharvest handling methods of chia seeds, as well as proper storage and an objective method of analyzing the moisture content of the chia seeds need to be developed.

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