Soybean (Glycine max (L.) Merr.) is an annual plant of the Fabaceae family. Native to East Asia, soybeans are now cultivated worldwide for various purposes, including oil production, proteins for human and animal consumption, and as a raw material for biofuel production [1]. It is a highly nutritious legume, rich in proteins (of high quality), lipids (many unsaturated fatty acids), carbohydrates, minerals (potassium, phosphorus, magnesium, iron, zinc, and calcium), vitamins (B9, B1 and E), and contains isoflavones, antioxidants and other bioactive substances beneficial to health [2][3]. Today, soybeans occupy a strategic position in global food systems due to their nutritional richness.

The evolution of eating habits, notably driven by consumers’ growing desire to substitute animal proteins with plant-based proteins, is increasing global demand for soybeans [4]. These numerous potentials of soybean seeds have led to an exponential increase in their worldwide production.

Indeed, global soybean production increased by 22% over the decade (2016-2026), reaching a record 428 million tonnes in 2025 [5]. The main producers are Brazil, United States, Argentina, China and Paraguay, which alone account for more than 80% of the world’s production. In Sub-Saharan Africa, soybean is the main source of protein for the most impoverished populations [6]. Regional production has shown strong growth in recent years, with 5.7 million tonnes produced in 2025, mainly driven by Nigeria, Benin and Togo.

In Benin, soybean production has increased significantly in recent years, reaching 520,929 tonnes in 2024 [7]. This production mainly relies on improved varieties, such as TGX (characterized by large grains and higher yields) and Jupiter (smaller grains) [8]. These varieties are preferred for their adaptation to local climatic and pedological conditions.

This nutritional and economic importance justifies the growing scientific interest in assessing the overall health quality of soybeans produced and marketed in Benin. Indeed, beyond its nutritional qualities, soybean can serve as a vector for microbiological, chemical and biotechnological hazards that could affect consumer health. In this context, evaluating nutritional quality is an essential preliminary step in assessing the value of the soy produced. However, an integrated approach to food safety also requires the identification and control of associated hazards, particularly microbiological, physico-chemical and biotechnological ones.

Regarding microbiological hazards, soy and soy-based products have been implicated in several foodborne illness outbreaks [9]. The presence of pathogenic bacteria in soy poses a real risk, as some derived products are consumed without sufficient thermal treatment. Therefore, the detection of microbiological pathogens is part of a preventive approach against collective food poisoning. Moreover, contamination of cereals and other staple crops by mycotoxins is a major public health concern. These toxins are produced by moulds and are recognized as genotoxic and carcinogenic [10]. It is therefore crucial to keep their levels in foodstuffs as low as possible. Consequently, mycotoxin quantification is an essential indicator of the sanitary quality and regulatory compliance of soybeans. Finally, the detection of Genetically Modified Organisms (GMOs) in soybeans is part of a dual requirement for food safety and transparency towards consumers. Indeed, soy is among the crops most affected by genetic modification worldwide. This raises questions about potential impacts on human health and the environment, as well as issues related to traceability and labelling. In this context, detecting GMOs in marketed plant products is essential to ensure regulatory compliance, inform consumers, and maintain control over agricultural supply chains.

In summary, the joint analysis of the nutritional quality and the microbiological, chemical, and biotechnological hazards of soybean seeds produced and marketed in Benin is part of a comprehensive food safety approach. It responds to the imperative of protecting public health, complying with international standards, and promoting local products within the context of globalized food trade. This study is conducted within this framework, which assesses the nutritional quality, microbiology and biotechnological aspects of soybean seeds produced and marketed in Benin.

The results regarding nutritional composition are generally in accordance with normative requirements and those reported in the literature. These results demonstrate the good quality of the seeds used by farmers and adherence to good production and drying practices.

The low moisture content observed could be explained, among other factors, by the fact that soybean seed sampling was carried out in March, a period of strong sunshine, across almost all regions of Benin. This result corroborates that of Bermegui Boni [18], who found moisture content in beninese soybean seeds ranging from 8 to 13%. The low moisture observed in this study is a favourable indicator of stability. Soybean seeds should be less susceptible to microbial development. Qin, et al. [1] emphasise the importance of this parameter in seed stability and the prevention of fungal contamination. Studies conducted in South America and Europe highlight that a rate below 13% significantly limits fungal and bacterial growth [19].

The analyzed soybean seeds have an average lipid content of 18.88%. This result complies with the beninese standard. It also conforms to the ARS 872 (2014) standard, which specifies a normal lipid content of 15% to 20%. The lipid content observed in our study is comparable to that reported by Bilyeu, et al. [2]. Studies conducted by Erliana [20] on 20 soybean lines in Indonesia revealed fat contents ranging from 19.28% to 21.95%. This high-lipid content confirms soy’s role as a major source of essential fatty acids with high energy value.

The protein contents (38.32%, average) observed in this study, although slightly below the beninese standard (≥40%), are in line with regional (ARS 872:2014) and international (ICS 67.060) standards, which set the normal protein content between 35% and 40%. In West Africa, studies indicate that contents range from 35% to 42%, reflecting variability influenced by cultivated varieties and agroecological conditions [6]. This variability is also confirmed globally, where factors such as soil fertility, farming practices, and environmental stresses influence protein biosynthesis [21].

The dietary fiber content of the soybean seeds obtained in this study (10.09%, average) is slightly above the Codex guideline limit (≤10%). These observed values are consistent with those reported in several international studies. Indeed, the fiber content of soybeans generally ranges from 8% to 12%, depending on variety and growing conditions (Yuhui Wang et al., 2021). The TGX soybean variety cultivated in Benin is very high in fiber. Thus, nutritionally, the soybean seeds produced and marketed in Benin meet international standards.

Conversely, the high levels of contamination of soybean seeds by TMAF observed in this study exceed those reported in certain african studies. For example, a study conducted in Nigeria by Adeyeye, et al. [22] showed significantly lower microbial loads. These differences may be explained by less rigorous post-harvest practices at local beninese markets. Indeed, the TMAF load is a good indicator of hygiene, which allows for an assessment of microbial pollution and the overall quality of food products [23].

The presence of Salmonella spp. in 20% of the samples is concerning and aligns with the observations of Ferrari et al. [9], who documented cases of soybean contamination involved in food poisoning incidents. This result highlights the need to strengthen hygiene measures and good harvesting and storage practices throughout the soybean value chain.

From a health perspective, soybeans pose a significant health risk due to the pathogenicity of Salmonella spp. Indeed, this pathogenic bacterium is among the main causes of foodborne illnesses worldwide [24]. This bacterium can cause various health problems, ranging from mild gastroenteritis to severe systemic conditions such as typhoid fever [25]. Globally, non-typhoidal Salmonella spp. infections are estimated to cause 938 million cases of gastroenteritis and approximately 155,000 deaths each year (Majowicz et al., 2010). Meanwhile, typhoid fever, caused by S. typhi, is responsible for 119 million cases and 128,000 deaths annually [26]. The impact of these diseases is particularly significant in low- or middle-income countries [27].

Regarding aflatoxins, the results are below the national and international standard threshold (4 µg/kg). However, our values are much lower than those reported in certain tropical regions, where concentrations exceeding 10 µg/kg have been observed [10]. This could be explained by less favourable local climatic conditions or relatively effective drying practices. The low level of total aflatoxins in beninese soybeans is a positive aspect, given their harmfulness. Indeed, contamination by mycotoxins, including aflatoxins, poses a food safety issue for cereals and other staple crops. Aflatoxins are secondary metabolites produced by Aspergillus flavus, A. parasiticus and A. nomius [28]. They contaminate a wide variety of foodstuffs, including cereals, nuts, dried fruits, spices, oilseeds, dried peas, beans and fruits [29]. Aflatoxins have been linked to liver lesions and cancer [30]. The contribution of aflatoxins to hepatocellular lesions is estimated at 4.6% - 28.2% in Sub-Saharan Africa, South-East Asia and China [31]. Consumption of aflatoxins also leads to other health issues, such as acute aflatoxicosis, immune deficiency and malnutrition-related disorders such as stunted growth [30].

Finally, the absence of genetically modified soy among the analysed samples contrasts with global trends, where more than 70% of soy is genetically modified [5]. However, this result is consistent with the agricultural policies of many African countries, where the adoption of transgenic crops remains limited. This situation reflects, among other factors, a low adoption of agricultural biotechnologies in West Africa, often linked to regulatory, economic, and societal constraints.

This study highlights the good nutritional quality of soybean seeds marketed in Benin, characterized by low moisture content, high lipid content and relatively high protein levels. However, microbiological deficiencies are observed, with elevated contamination levels and Salmonella spp. detected in a significant proportion of samples, posing a risk to public health. Aflatoxin levels remain within international standards, and no targeted GM markers detected. These results emphasise the need to strengthen good hygiene and storage practices throughout the entire production and marketing chain.

The sampling of soybeans was carried out over a period of less than two months (January to February). This was a period of high temperatures. What about other periods of the year?

Conceptualisation: L.B.-M., F.B.-M., M.N.E.A.M., T.F.G.D., C.S.K., and H.L.; Methodology: M.N.E.A.M., T.F.G.D., C.S.K. and A.D.P.N.; Software: M.N.E.A.M., T.F.G.D., C.S.K. and A.D.P.N.; Validation, M.N.E.A.M., T.F.G.D., C.S.K. and H.L. ; Formal Analysis: M.N.E.A.M., T.F.G.D., C.S.K., H.L. and A.D.P.N.; Investigation: M.N.E.A.M., T.F.G.D., C.S.K. and H.L.; Resources: M.N.E.A.M., T.F.G.D., C.S.K. and H.L. ; Data Retention: M.N.E.A.M., T.F.G.D., C.S.K. and H.L.; Writing: preparation of the original version: M.N.E.A.M., T.F.G.D., C.S.K., H.L. and A.D.P.N.; Proofreading and Editing: M.N.E.A.M., T.F.G.D., C.S.K., H.L and A.D.P.N.; Visualization: M.N.E.A.M., T.F.G.D., C.S.K., H.L., and F.B.-M.; Supervision: M.N.E.A.M., T.F.G.D., C.S.K., H.L., L.B.-M. and F.B.-M.; Project Administration: M.N.E.A.M., T.F.G.D. and C.S.K.; Search for funding: M.N.E.A.M., T.F.G.D. and C.S.K.

All authors have read and agreed to the published version of the manuscript.

The experimental protocol was approved by the Scientific Ethics Committee of the Doctoral School (Life Sciences) of the University of Abomey-Calavi (UAC), Benin, under number UAC/FAST/EDSVT/10037907.