Quantitative microbiological risk assessment, physicochemical quality and sensory profiles of artisanal cashew wine and zobo compared with commercial grape wines in Nigeria

Artisanal fermented and non-alcoholic beverages are widely consumed in Nigeria, yet their microbiological safety is rarely quantified alongside their physicochemical and sensory quality. This study compared artisanal cashew wine and zobo with commercial red and rosé wines. Eight microbial groups were enumerated by spread plating, and the staphylococcal isolate was confirmed as coagulase positive. A growth-coupled quantitative microbial risk assessment used a square-root model with temperature and pH terms and 50,000 Monte Carlo iterations. Physicochemical properties were compared by one-way analysis of variance and principal component analysis, while 20 panelists scored sensory attributes on a 5-point scale. Detected counts ranged from 1.30 to 3.00 log CFU mL⁻¹, and faecal coliforms, moulds and pseudomonads were not detected. Artisanal beverages carried the highest microbial loads, notably coagulase-positive staphylococci in cashew wine (3.00 log CFU mL⁻¹) and acetic acid bacteria in zobo (2.58 log CFU mL⁻¹). At the measured pH of 3.28, no simulated cashew wine serving reached the 5-log toxigenic threshold under any storage scenario, whereas a pH-permissive-worst case at 24 to 34 °C reached it in 72.4% of servings within 12 h. Beverage pH ranged from 3.17 to 3.38, and the first principal component (68.0%) separated sugar-rich zobo from the wines. Zobo scored at least as high as red wine on 12 of 13 attributes. Acidity, rather than contamination level, governed staphylococcal risk, although the staphylococcal count signals post-fermentation hygiene failure.