For many Ghanaians, olewonyo (Asaana) is more than just a refreshing drink. Made from fermented caramelised corn, it is sold in markets and by roadside vendors, providing both nourishment and a source of income. However, producers often face one major challenge: the drink can go bad within a few days, leading to waste and lost income.
To understand why this happens, KNUST researchers Prof. Matthew Glover Addo, Prof. Linda Aurelia Ofori and Prof. Kwasi Obiri-Danso compared olewonyo purchased from the Aboabo and Anloga suburbs of the Ashanti Region with a version prepared under controlled laboratory conditions.
Over three days, they monitored the number of microorganisms in each sample, as well as changes in acidity and pH, two important indicators of food spoilage.
The results showed that the drinks bought from local producers quickly became crowded with microorganisms. Within just three days, the number of bacteria had increased dramatically, while the drink became much more acidic during the first 24 hours. This rapid change explains why olewonyo (Asaana) develops a sour taste and spoils so quickly when stored at room temperature.
The laboratory-produced sample behaved differently. Because it was prepared under cleaner and more controlled conditions, microorganisms multiplied more slowly, and the drink remained stable for a longer period. This suggests that improving hygiene during production could help extend the shelf life of olewonyo (Asaana).
The researchers also identified the tiny organisms responsible for these changes. They found lactic acid bacteria (Lactobacillus plantarum, Lactobacillus fermentum and Leuconostoc mesenteroides), which convert sugars in the drink into acids. While these bacteria are commonly used in producing foods such as yoghurt and other fermented products, they can also make beverages like olewonyo (Asaana) spoil more quickly when their growth is not controlled.
The study also detected yeasts (Saccharomyces cerevisiae and Candida krusei) and moulds, including Aspergillus niger, Aspergillus flavus and Aspergillus fumigatus. Their presence points to possible contamination during preparation, handling or storage and highlights the need for better sanitation practices.
The message from the study is straightforward: how olewonyo (Asaana) is prepared and stored matters. Cleaner equipment, safer handling practices and proper storage can slow the growth of spoilage microorganisms, helping the drink stay fresh for longer. This could reduce waste, improve food safety and increase profits for local producers.
Story: Emmanuel Kwasi Debrah
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