Article

Assessment of Antinutrients, Heavy Metals, and Microbial Load in Street-Vended Foods from Port Harcourt, Nigeria

Owo Gogo James ORCID , Austin Achinike Okwelle ORCID , Enyohwo Dennis Kpomah ORCID
    Received
    13 Sep 2025
    Published
    23 Jul 2025

    Abstract

    Street-vended foods are a vital source of affordable nutrition for many urban dwellers but can pose serious public health risks due to several factors. This study evaluated antinutrient levels, heavy-metal contamination, and microbiological quality of abacha, tapioca, roasted plantain, fried yam, and okpa sold at key commercial areas in Port Harcourt. A stratified cross-sectional design was used, with 225 samples (15 per food type per site) collected from Eleme Junction, Artillery, and Waterlines. Antinutrients were determined spectrophotometrically, while heavy metals were analysed using inductively coupled plasma mass spectrometry (ICP-MS) and atomic absorption spectrophotometry (AAS). Microbiological quality was assessed through total viable count (TVC), bacterial, coliform, and fungal counts expressed as log10 cfu/g. Abacha from Artillery showed the highest phytate (5.02 ± 0.21 mg/g) and tannin (3.28 ± 0.16 mg/g), while okpa from the same site had the highest saponin (3.02 ± 0.18 mg/g). Tapioca from Eleme Junction recorded the highest oxalate (2.56 ± 0.14 mg/g). Heavy-metal analysis revealed that roasted plantain from Artillery had the highest Pb level (176.4 ± 4.2 µg/kg), far above the WHO/FAO limit of 100 µg/kg; Cd (38.5–62.7 µg/kg) and As (45.6–58.3 µg/kg) also exceeded permissible limits, while Fe and Zn levels were relatively high. Microbiological findings showed TVC values ranging from 3.25–7.42 log10 cfu/g, with roasted plantain from Artillery recording the highest bacterial load, and coliforms most prevalent in abacha. Overall, foods sold at Artillery demonstrated the greatest contamination, highlighting the urgent need for stronger regulatory inspection and improved vendor hygiene training.

    Keywords

    Antinutrient, Food Safety, Heavy Metals, Microbial Quality, Port Harcourt, Roadside Foods

    References
    1. [1]World Health Organization (WHO), 2022. WHO Global Strategy for Food Safety 2022–2030: Towards Stronger Food Safety Systems and Global Cooperation. World Health Organization: Geneva, Switzerland. Available from: https://www.who.int/publications/i/item/9789240057685
    2. [2]Alimi, B.A., 2016. Risk Factors in Street Food Practices in Developing Countries: A Review. Food Science and Human Wellness. 5(3), 141–148. DOI: https://doi.org/10.1016/j.fshw.2016.05.001
    3. [3]Mazi, I.M., Onyeaka, H., Akegbe, H., et al., 2023. Street Vended Foods in Nigeria: An Analysis of the Current State of Affairs and the Way Forward. Cogent Food & Agriculture. 9(2), 2266194. DOI: https://doi.org/10.1080/23311932.2023.2266194
    4. [4]Samuel, O.O., 2012. Bacteriological Quality and Safety of Street Vended Foodsin Delta State, Nigeria. Journal of Biology, Agriculture and Healthcare. 2(5). Available from: https://www.iiste.org/Journals/index.php/JBAH/article/view/1991
    5. [5]Nneoma, U.C., 2024. Understanding the Risk Landscape: Analyzing Factors Impacting Food Vending in Nigeria. INOSR Experimental Sciences. 13(1), 72–79. DOI: https://doi.org/10.59298/INOSRES/2024/1.72.7910
    6. [6]Okojie, P.W., Isah, E.C., 2014. Sanitary Conditions of Food Vending Sites and Food Handling Practices of Street Food Vendors in Benin City, Nigeria: Implication for Food Hygiene and Safety. Journal of Environmental and Public Health. 2014, 1–6. DOI: https://doi.org/10.1155/2014/701316
    7. [7]Were, L., Were, G., Aduol, K.O., 2020. Hygiene Practices and Microbial Contamination of Street-Vended Foods in Kenyatta University’s Environs. European Journal of Agriculture and Food Sciences. 2(5). DOI: https://doi.org/10.24018/ejfood.2020.2.5.105
    8. [8]Abera, S., Yohannes, W., Chandravanshi, B.S., 2023. Effect of Processing Methods on Antinutritional Factors (Oxalate, Phytate, and Tannin) and Their Interaction with Minerals (Calcium, Iron, and Zinc) in Red, White, and Black Kidney Beans. International Journal of Analytical Chemistry. 2023, 1–11. DOI: https://doi.org/10.1155/2023/6762027
    9. [9]Mamiro, P.S., Mwanri, A.W., Mongi, R.J., et al., 2017. Effect of Cooking on Tannin and Phytate Content in Different Bean (Phaseolus Vulgaris) Varieties Grown in Tanzania. African Journal of Biotechnology. 16(20), 1186–1191. DOI: https://doi.org/10.5897/AJB2016.15657
    10. [10]Bayata, A., 2019. Review on Nutritional Value of Cassava for Use as a Staple Food. Science Journal of Analytical Chemistry. 7(4), 83. DOI: https://doi.org/10.11648/j.sjac.20190704.12
    11. [11]Kiran, Bharti, R., Sharma, R., 2022. Effect of Heavy Metals: An Overview. Materials Today: Proceedings. 51, 880–885. DOI: https://doi.org/10.1016/j.matpr.2021.06.278
    12. [12]Jomova, K., Alomar, S.Y., Nepovimova, E., et al., 2025. Heavy Metals: Toxicity and Human Health Effects. Archives of Toxicology. 99(1), 153–209. DOI: https://doi.org/10.1007/s00204-024-03903-2
    13. [13]Zaynab, M., Al-Yahyai, R., Ameen, A., et al., 2022. Health and Environmental Effects of Heavy Metals. Journal of King Saud University-Science. 34(1), 101653. DOI: https://doi.org/10.1016/j.jksus.2021.101653
    14. [14]Harmanjit, K., Kaur, H., Kaur, H., et al., 2023. The Beneficial Roles of Trace and Ultratrace Elements in Plants. Plant Growth Regulation. 100(2), 219–236. DOI: https://doi.org/10.1007/s10725-022-00837-6
    15. [15]Oyet, G.I., Achinewhu, S.C., Kiin-Kabari, D.B., et al., 2020. Microbiological Quality of Selected Street Vended Foods During Wet and Dry Season in Parts of Port Harcourt Metropolis, Rivers State, Nigeria. Research Journal of Food Science and Nutrition. 5(2), 35–45. DOI: https://doi.org/10.31248/RJFSN2020.091
    16. [16]Adegbite, K.I., Towolawi, A.T., Oladeji, F.O., et al., 2025. Assessment of Heavy Metal Contamination across Five Selected Roadside Marketed Fruits in Erin-Osun, Osun State, Nigeria. Fountain Journal of Basic Medical and Health Sciences. 1(2), 1–13. Available from: https://www.fountainjournals.com/index.php/FUJBMHES/article/view/809
    17. [17]Solomon, A.K., Lilian, N.N., Mary, O.A., 2025. Microbial Quality of Street Prepared and Vended Snacks in Umuahia Town, South East Nigeria. Journal of Food Safety and Hygiene. 10(3). DOI: https://doi.org/10.18502/jfsh.v10i3.18354
    18. [18]Gitau, G., Muasya, D., Mwangi, W., et al., 2025. Risk Factors Associated with Camel Milk Total Coliform and Total Viable Bacterial Count Along the Camel Milk Value Chain in Isiolo County, Kenya. Journal of Research in Veterinary Sciences. 5(1), 29. DOI: https://doi.org/10.5455/JRVS.20241215111750
    19. [19]Omorodion, N.J.P., Ogunekum, A., 2022. Microbial and Physicochemical Screening of Ready to Eat Street Foods. Asian Journal of Basic Science & Research. 4(1), 24–35. DOI: https://doi.org/10.38177/AJBSR.2022.4103
    20. [20]Makinde, O.M., Ayeni, K.I., Sulyok, M., et al., 2020. Microbiological Safety of Ready‐to‐Eat Foods in Low‐ and Middle‐Income Countries: A Comprehensive 10‐Year (2009 to 2018) Review. Comprehensive Reviews in Food Science and Food Safety. 19(2), 703–732. DOI: https://doi.org/10.1111/1541-4337.12533
    21. [21]Udousoro, I., Akpan, E., 2014. Changes in Anti-Nutrients Contents of Edible Vegetables Under Varied Temperature and Heating Time. Current Research in Nutrition and Food Science Journal. 2(3), 146–152. DOI: https://doi.org/10.12944/CRNFSJ.2.3.06
    22. [22]Balyatanda, S.B., Gowda, N.A.N., Subbiah, J., et al., 2024. Physiochemical, Bio, Thermal, and Non-Thermal Processing of Major and Minor Millets: A Comprehensive Review on Antinutritional and Antioxidant Properties. Foods. 13(22), 3684. DOI: https://doi.org/10.3390/foods13223684
    23. [23]Mitchell, T., Kumar, P., Reddy, T., et al., 2019. Dietary Oxalate and Kidney Stone Formation. American Journal of Physiology-Renal Physiology. 316(3), F409–F413. DOI: https://doi.org/10.1152/ajprenal.00373.2018
    24. [24]Ogunka-Nnoka, C.U., Abbey, B.W., 2019. Bioactive Components and the Effect of Aqueous Leaf Extract of Maesobotrya Barteri (Baill.) Hutch. (Euphorbiaceae) on Haematological Profile in Paracetamol-Induced Wistar ratsBioactive Components and the Effect of Aqueous Leaf Extract of Maesobotrya Barte. Brazilian Journal of Biological Sciences. 6(14), e409. DOI: https://doi.org/10.21472/bjbs.061405
    25. [25]Oleszek, M., Oleszek, W., 2020. Saponins in Food. In: Xiao, J., Sarker, S.D., Asakawa, Y. (Eds.). Handbook of Dietary Phytochemicals. Springer: Singapore. pp. 1–40. DOI: https://doi.org/10.1007/978-981-13-1745-3_34-1
    26. [26]Erhirhie, E., Nwosu, C., Emudainohwo, T., et al., 2020. Health Hazards Associated with Ready-to-Eat-Meat in Nigeria: A Call for Public Concern and Critical Interventions. Meat Technology. 61(2), 129–144. DOI: https://doi.org/10.18485/meattech.2020.61.2.3
    27. [27]World Health Organization (WHO), 2019. Cadmium in Drinking-Water: Background Document for Development of WHO Guidelines for Drinking-water Quality. World Health Organization: Geneva, Switzerland. Available from: https://www.who.int/docs/default-source/wash-documents/wash-chemicals/cadmium-chemical-fact-sheet.pdf
    28. [28]Moronkola, B.A., Alegbe, M.J., Adewusi, A., et al., 2019. Determination of Heavy Metals in Roasted and Unroasted Plantain Purchased from Selected Areas in Lagos State. Quest Journals: Journal of Research in Environmental and Earth Sciences. 9(3), 63–68. Available from: https://www.questjournals.org
    29. [29]Balali-Mood, M., Naseri, K., Tahergorabi, Z., et al., 2021. Toxic Mechanisms of Five Heavy Metals: Mercury, Lead, Chromium, Cadmium, and Arsenic. Frontiers in Pharmacology. 12, 643972. DOI: https://doi.org/10.3389/fphar.2021.643972
    30. [30]World Health Organization (WHO), 2022. Chemical Hazards in Drinking-Water: Arsenic. World Health Organization: Geneva, Switzerland. Available from: https://www.who.int/teams/environment-climate-change-and-health/water-sanitation-and-health/chemical-hazards-in-drinking-water
    31. [31]Akinyele, I.O., Shokunbi, O.S., 2015. Concentrations of Mn, Fe, Cu, Zn, Cr, Cd, Pb, Ni in Selected Nigerian Tubers, Legumes and Cereals and Estimates of the Adult Daily Intakes. Food Chemistry. 173, 702–708. DOI: https://doi.org/10.1016/j.foodchem.2014.10.098
    32. [32]Oyet, G.I., Samuel, C.B., 2020. Safety Assessment of the Presence of Heavy Metals and Organic Pollutants in Vended Street Foods from Selected Locations in Lagos State Nigeria. European Journal of Nutrition & Food Safety. 109–120. DOI: https://doi.org/10.9734/ejnfs/2020/v12i630251
    33. [33]Erickson, M.C., Liao, J., Cannon, J.L., et al., 2015. Contamination of Knives and Graters by Bacterial Foodborne Pathogens During Slicing and Grating of Produce. Food Microbiology. 52, 138–145. DOI: https://doi.org/10.1016/j.fm.2015.07.008
    34. [34]Ebert, M., 2018. Hygiene Principles to Avoid Contamination/Cross-Contamination in the Kitchen and During Food Processing. In Staphylococcus Aureus. Elsevier: New York, NY, USA. pp. 217–234. DOI: https://doi.org/10.1016/B978-0-12-809671-0.00011-5
    35. [35]Okoli, C.E., Njoga, E.O., Enem, S.I., et al., 2018. Prevalence, Toxigenic Potential and Antimicrobial Susceptibility Profile of Staphylococcus Isolated from Ready-to-Eat Meats. Veterinary World. 11(9), 1214–1221. DOI: https://doi.org/10.14202/vetworld.2018.1214-1221
    36. [36]Mahunu, G.K., Osei-Kwarteng, M., Ogwu, M.C., et al., 2024. Safe Food Handling Techniques to Prevent Microbial Contamination. In: Ogwu, M.C., Izah, S.C., Ntuli, N.R. (Eds.). Food Safety and Quality in the Global South. Springer Nature: Singapore, pp. 427–461. DOI: https://doi.org/10.1007/978-981-97-2428-4_14
    37. [37]Kariuki, E.N., Ng'ang'a, Z.W., Wanzala, P., 2017. Food-Handling Practices and Environmental Factors Associated With Food Contamination Among Street Food Vendors in Nairobi County, Kenya: A Cross-Sectional Study. East African Health Research Journal. 1(1), 62–71. Available from: https://pubmed.ncbi.nlm.nih.gov/34308160/
    38. [38]Onyango, A.E., Okoth, M.W., Kunyanga, C.N., et al., 2018. Microbiological Quality and Contamination Level of Water Sources in Isiolo County in Kenya. Journal of Environmental and Public Health. 2018, 1–10. DOI: https://doi.org/10.1155/2018/2139867
    39. [39]Okwelle, A.A., Amadi-Ikpa, C.N., 2024. Screening for Salmonella spp. in Food, Water, and Hands of Households in Rumuwoji, Port Harcourt, Nigeria. Faculty of Natural and Applied Sciences Journal of Scientific Innovations.5(3), 35–39. Available from: https://fnasjournals.com/index.php/FNAS-JSI/article/view/270
    40. [40]Navaneethan, Y., Effarizah, M.E., 2023. Post-Cooking Growth and Survival of Bacillus Cereus Spores in Rice and Their Enzymatic Activities Leading to Food Spoilage Potential. Foods. 12(3), 626. DOI: https://doi.org/10.3390/foods12030626
    41. [41]Azad, Z.R.A.A., Ahmad, M.F., Siddiqui, W.A., 2019. Food Spoilage and Food Contamination. In: Malik, A., Erginkaya, Z., Erten, H. (Eds.). Health and Safety Aspects of Food Processing Technologies. Springer International Publishing: Cham, Switzerland. pp. 9–28. DOI: https://doi.org/10.1007/978-3-030-24903-8_2
    Back to top