Venoms and Toxins   Send Orders for Reprints to reprints@benthamscience.net Venoms and Toxins, 2022, 2, e120122200168 RESEARCH ARTICLE Detection of Enterotoxin Genes in Bacillus species Isolated from Cassava Processing Environment in Nigeria 62 Nkem Torimiro 1 , Oluwafemi B. Daramola 1,* , Richard K. Omole 1 and Ifeyimika Z. Adesina 1 1 Department of Microbiology, Obafemi Awolowo University, 220005, Ile-Ife, Nigeria ARTICLE HISTORY Received: July 27, 2021 Revised: October 29, 2021 Accepted: November 29, 2021 DOI: 10.2174/2666121702666220112101938 Abstract: Introduction: The health challenges associated with cassava products as a common sta- ple food for approximately 70 % of Africans and part of Asia pose a looming danger due to Bacil- lus enterotoxins’ presence in the processing environment. Objective: This study investigated the presence of enterotoxigenic genes, namely, Bacillus cereus enterotoxin T (bceT), hemolysin bl (hblC, hblD), and non-haemolytic enterotoxin (nheA, nheB, and nheC) from Bacillus species isolated from soil of cassava processing environment. Methods: Soil samples from 20 cassava processing sites in Ile-Ife and Modakeke, Nigeria, were collected and cultured on nutrient agar at 37ºC for 24 hours. Colonies phenotypically identified as Bacillus were identified using Bacillus-specific 16S rRNA-targeted PCR technique. Screened Bacil- lus spp were assessed for the presence of enterotoxigenic genes using PCR with previously report- ed primers. Results: A total of 100 Bacillus isolates were selected from this study, with Bacillus macerans (33 %) showing the highest frequency of occurrence among the identified species, however, 74 isolates were molecularly confirmed as Bacillus. Amongst the 74 molecularly confirmed Bacillus isolates, 28 (37.84 %), 35 (47.30 %), and 37 (50 %) had nhe, hbl, and bceT genes, respectively. Investiga- tion showed that 42 (56.76 %) of the Bacillus species encoded at least one of the screened entero- toxin genes. Conclusion: The presence of these 3 sets of enterotoxin genes in Bacillus isolated from cassava processing sites calls for immediate attention as they could be pivotal in the release of toxins in cas- sava products, causing lethal effects via consumption. This study demonstrates the possibility of foodborne disease outbreaks in Bacillus toxin-laden cassava products processed under unhygienic conditions. Keywords: Bacillus toxins, food safety, foodborne disease, enterotoxigenic genes, cassava, hygienic practices. 1. INTRODUCTION Cassava (Manihot esculenta) is a food and cash crop that contributes significantly to the daily dietary intake of the populace in the tropics and many African countries [1, 2]. It is a major carbohydrate source that yields varieties of tradi- tional diets with different characteristics such as garri, Indo- nesian tape, attieke, chips, beer, fritters, pastries, starch, fufu, lafun, pupuru, agbelima, attoukpou, among others [3-5]. High toxic cyanogenic glucosides content such as lac- tic, acetic, propanoic, and butanoic acids have been reported in some varieties of cassava. Fortunately, the release of liquid effluent during cassava fermentation has ensured ap- preciable reduction of these organic compounds in cassava *Address correspondence to this author at the Department of Microbiology, Obafemi Awolowo University, 220005, Ile-Ife, Nigeria; E-mail: oluwafemidaramola8@gmail.com products [5]. Apart from the constant release of these acids which tends to increase the acidity of soil in such environ- ment, it also plays some role in influencing the microbial di- versity in such environment by accommodating the survival of acid-tolerant microbes. Bacillus, a member of the phylum Firmicutes, is a large, heterogenous and ubiquitous group of Gram-positive bacte- ria that play significant roles in the ecosystem [6]. Bacillus species are one of the important microorganisms of the soil microbial community. They are abundant and relatively high in extreme environments, such as acidic soils [7], saline-alka- li soils [8], and desert soils [9]. It has been reported that vari- ous Bacillus species can ferment cassava to produce amy- lase enzyme [10], which is useful for starch hydrolysis. Ba- cillus species involvement as spontaneous culture in both solid-state and submerged fermentation of cassava is well ac- cepted due to their survival rate in harsh conditions. As a re- sult, they have gained wide application in various industries 2666-1225/22 $65.00+.00 ©2022 Bentham Science Publishers