Microbial and heavy metal hazard analysis of edible tomatoes (Lycopersicon esculentum) in Port Harcourt, Nigeria

Objective: This study investigated the health risks from tomato consumption with regard to microbial contaminants and heavy metal content of fresh and stale tomatoes (Lycopersicon esculentum) sold in selected markets within Port Harcourt metropolis, Nigeria. Materials and Methods: Standard microbiological procedures were employed for the determination of microbial density while flame atomic absorption spectrometry was used for heavy metal analysis. Results: Results showed values of chromium, copper, manganese, zinc, total heterotrophic bacteria and total fungi ranging from 0.396 to 0.896 mg/kg, 0.602 to 2.434 mg/kg, < 0.001 to 1.770 mg/kg, 0.110 to 2.048 mg/kg, 2.300 × 106 CFU/g to 7.167 × 106 CFU/g and 1.467 × 105 CFU/g to 2.767 × 105 CFU/g, respectively. There were significant variations (p < 0.05) across the different markets for all test parameters except total fungi. Cadmium and lead were not detected in the tomatoes. The estimated daily intake of metals from consumption of tomatoes in the study areas was less than the maximum tolerable daily intake. The total hazard quotient and health index were < 1, an indication of no associated adverse health effect. Among the metals studied, there was no carcinogenic risk of lead and cadmium given they were below measurable detection limit; however, the ingestion of tomatoes containing chromium in the study area was within permissible predicted lifetime risks of carcinogens (10−6–10−4), while the microbial density was far higher than acceptable (≤ 103 CFU/g), but close to tolerable (104–105 CFU/g) for total fungi limits in food as specified by the International Commission on Microbiological Specifications for Foods. Conclusion: The high microbial density indicates unsanitary practices by local vendors. As a result, it is important to frequently assess microbial load and potential metal contamination of tomatoes to forestall potential health concerns linked with their consumption, especially the immuno-toxicological effects of metal toxicity.