Contents lists available at ScienceDirect Food Control journal homepage: www.elsevier.com/locate/foodcont Virulence potentials of Bacillus strains recovered from edible snails and survival during culinary preparation Arthur C. Okafor a, ⁎ , Frank C. Ogbo b a Department of Microbiology, Edo University Iyamho, Edo State, Nigeria b Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University, Awka, Nigeria ARTICLE INFO Keywords: Achatina achatina Bacillus cereus B. thuringiensis Food safety Enterotoxin genes Potassium alum ABSTRACT Some Bacillus species are underestimated pathogens which commonly occur as irregular cases, rather than in major outbreaks. There are reports confirming the consistent presence of Bacillus species in edible snails. This study aimed to assess, by molecular studies, the virulent nature of some Bacillus strains in live edible snails (Achatina achatina) sold in Nigerian markets and to ascertain the survival of bacilli during culinary preparation. Results showed that isolates with high virulence potentials were B. thuringiensis and two strains of B. cereus (GenBank accession numbers: MK530172, MK530171 and MK530202). The nheb gene was detected in all three isolates, while B. thuringiensis strain was found to possess hbla, nhea, nheb and cytk genes for enterotoxins often implicated in diarrhoea cases. Most isolates were resistant to chloramphenicol and norfloxacin. The stages of culinary preparation of snail meat could not reduce bacilli counts below allowable limits. Therefore, A. achatina may be a neglected source of virulent strains of Bacillus in the food chain. We envisage that cross contamination during handling and preparation of edible snails along the food chain will put the health of handlers and consumers at risk, especially in the rural population. Proper hygiene during handling and culinary preparation is recommended. 1. Introduction Foodborne diseases create a significant burden of disability and mortality in most countries. Recent assessments specify that more than half a billion incidences of foodborne disease occur yearly and about 420,000 deaths (WHO 2015). Foodborne diseases and death propor- tions among all ages occur more frequently in developing countries (Havelaar, 2016). A contaminated food, regardless of the level of ha- zards, threatens the health and economy of nations (Mensah, Mwamakamba, Mohammed, & Nsue-Milang, 2012). Foodborne infection is common in Nigeria with more than a million cases yearly and most cases are not reported (FMoH 2014). It has been estimated that more than 200,000 deaths occur per annum from foodborne pathogens caused by contaminated foods through improper processing, preservation and service in Nigeria (WHO 2009). Although all food groups add to the burden of foodborne diseases, foods of animal origin have been reported to cause the highest burden (Havelaar, 2016). Achatina achatina is a terrestrial gastropod of the family “Achatinidae” which has been listed among edible snails (EC 2004). World snail consumption is at 400,000 tons of snails between 2010 and 2011, of which only 50,000 tons were produced in snail farms (Toader, 2012). In Nigeria, the annual demand for snail among consumers is about 7.5 million kg (Agbaji, 2018). They are sold alive as food commodities in the wet markets and are usually obtained from the wild (Nyoagbe, Appiah, Nketsia- Tabiri, Larbi, & Adjei, 2016). Snails are consumed by the people of both rural and urban communities (Efuntoye, Mabekoje, & Adekoya, 2011). It has been reported that 70% of the populace in Bori, southern Nigeria do consume snail meat (Nodu, Adesope, & Matthews-Njoku, 2003). Also, they are usually purchased alive in the market by consumers and brought into homes where they are handled and cooked in the domestic kitchens. Unfortunately, snail meat is more prone to microbial contamination than meat from other animals, be- cause snails are in continuous contact with soil and debris thereby exposed to various microorganisms. Also, regular consumers of snails are often plagued by mild gastroenteritis (Serrano, Medina, Jurado, & Jodral, 2004). Bacillus cereus, which causes the diarrhoeal syndrome, produces basically three enterotoxins: haemolytic, non-haemolytic and cytotoxin K(Glasset et al., 2016; Owusu-Kwarteng, Wuni, Akabanda, Tano- Debrah, & Jespersen, 2017). Previous studies have affirmed that it is an underrated evolving pathogen which can be involved in severe illnesses https://doi.org/10.1016/j.foodcont.2019.106834 Received 6 May 2019; Received in revised form 7 August 2019; Accepted 19 August 2019 ⁎ Corresponding author. E-mail address: arthur.okafor@edouniversity.edu.ng (A.C. Okafor). Food Control 108 (2020) 106834 Available online 19 August 2019 0956-7135/ © 2019 Elsevier Ltd. All rights reserved. T