ACU Don Warns Nigerians Against Improper Food Storage, Highlights Microbial Risks

A Professor of Food Microbiology at Ajayi Crowther University (ACU), Oyo, Prof. Afolake Atinuke Olanbiwoninu, has urged Nigerians to observe proper food storage temperatures to prevent foodborne illnesses.

Prof. Olanbiwoninu gave the warning while delivering the 32nd Inaugural Lecture of the university on Tuesday, October 6, 2026. The lecture was titled “Invisible Giants: The Microbial Forces Securing Food, Protecting Health and Sustaining Life on Earth.”

The don emphasised the importance of the 2-Hour/4-Hour Rule, explaining that food becomes unsafe when exposed to the Temperature Danger Zone, between 5°C and 60°C, for extended periods.

She explained that food kept within the danger zone for less than two hours can either be used or chilled. Where it has remained there for between two and four hours, it should be consumed immediately, while food kept beyond four hours should be discarded.

She stressed that seasoning cannot substitute for proper food-handling practices, regardless of the antimicrobial properties of the ingredients used.

Using her research on the “Survival Pattern and Toxin Production of Pathogens in Spiced and Non-Spiced Fried Rice” as an example, Prof. Olanbiwoninu noted that ready-to-eat foods served at Nigerian weddings, conferences, religious gatherings and other social events are often prepared in large quantities ahead of time and kept at ambient temperatures before serving.

According to the Deputy Vice-Chancellor (Academic), findings from the study showed that pathogenic organisms, including Escherichia coli, Salmonella typhi, Bacillus cereus and Staphylococcus aureus, multiplied rapidly as holding temperatures decreased and storage periods increased.

She said food poisoning outbreaks linked to social gatherings may not necessarily result from poorly cooked food, but could arise from improper handling after cooking.

Prof. Olanbiwoninu acknowledged that spices such as garlic, ginger, thyme and curry could inhibit microbial growth to varying degrees. However, she cautioned that their antimicrobial properties should not be interpreted as eliminating foodborne pathogens or preventing toxin production during prolonged storage.

She also discussed the food safety risks associated with fresh fruits and vegetables, noting that fruits are generally consumed without heat treatment capable of destroying pathogenic microorganisms.

The inaugural lecturer cited her research into microorganisms associated with spoiled tomatoes sold in local markets, popularly known as “esha” in Yoruba. She explained that economic difficulties often force consumers to purchase partially spoiled tomatoes because they are cheaper.

Her investigations identified several bacterial and fungal species associated with the spoiled tomatoes, with a number of the organisms showing high levels of antimicrobial resistance.

Prof. Olanbiwoninu stressed that food-related consumer behaviour is shaped not only by scientific knowledge but also by economic realities. She therefore called for food safety interventions that take into account the relationship between poverty, food security, market conditions and public health.

Describing microorganisms as “invisible giants,” she said they play important roles in sustaining ecosystems, recycling nutrients, enriching soils, preserving foods, improving nutrition, protecting public health and providing innovative solutions to national challenges.

She called for microbiology and biotechnology to be given greater prominence in Nigeria’s national development strategies, particularly as the country seeks to strengthen food security, improve public health, diversify its economy and develop a resilient bioeconomy.

Among her recommendations, she urged government, academia, industry and development partners to promote indigenous fermented foods, strengthen national food safety systems, increase investment in microbiology and biotechnology, address micronutrient deficiencies and improve antimicrobial resistance surveillance through a One Health approach.

She also called for microbiology to be recognised as a strategic national intellectual asset.

Earlier, the Vice-Chancellor of ACU, Prof. Ebunoluwa Oduwole, described Prof. Olanbiwoninu as a multiple research grant and award winner who had made significant contributions to the development of the university.

The lecture was attended by the immediate past Vice-Chancellor, Prof. Timothy Adebayo, alongside other dignitaries from various sectors.