Safety of yam-derived (Dioscorea rotundata) foodstuffs—chips, flakes and flour: Effect of processing and post-processing conditions

The production of yam-derived (Dioscorea rotundata) foodstuffs is mainly performed by small and medium scale processors that employ old traditional methods. This can lead to differences in quality from processor to processor, and from location to location, with consequent safety concerns. As such, the effects of processing and post-processing phases (i.e., storage, transport, etc.) on the safety of some yam-derived foodstuffs—namely chips, flakes, and flour—has been evaluated, with a focus on bacterial and fungal contamination, aflatoxins, pesticides, and heavy metals (Pb, Ni, Cd and Hg). Yams harvested and processed in Nigeria were screened, being that the country is the largest producer of the tuber, with 70–75% of the world production. Results highlighted no presence of pesticides, however, many samples showed high levels of bacterial and fungal contamination, together with heavy metal concentrations above the recommended safety levels. No trend was observed between the items considered; it was noticed, however, that samples purchased from the markets showed higher contamination levels than those freshly produced, especially regarding bacterial and aflatoxins presence. The processing stage was identified as the most critical, especially drying. Nonetheless, post-processing steps such as storage and handling at the point of sale also contributed for chemical contamination, such as aflatoxin and heavy metals. The results suggested that both the processing and post-processing phases have an impact on the safety of yam chips, flakes, and flour

Immunological insights into COVID-19 in Southern Nigeria

Introduction: One of the unexpected outcomes of the COVID-19 pandemic was the relatively low levels of morbidity and mortality in Africa compared to the rest of the world. Nigeria, Africa's most populous nation, accounted for less than 0.01% of the global COVID-19 fatalities. The factors responsible for Nigeria's relatively low loss of life due to COVID-19 are unknown. Also, the correlates of protective immunity to SARS-CoV-2 and the impact of pre-existing immunity on the outcome of the COVID-19 pandemic in Africa are yet to be elucidated. Here, we evaluated the natural and vaccine-induced immune responses from vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria throughout the three waves of the COVID-19 pandemic in Nigeria. We also examined the pre-existing immune responses to SARS-CoV-2 from samples collected prior to the COVID-19 pandemic. Methods: We used spike RBD and N- IgG antibody ELISA to measure binding antibody responses, SARS-CoV-2 pseudotype assay protocol expressing the spike protein of different variants (D614G, Delta, Beta, Omicron BA1) to measure neutralizing antibody responses and nucleoprotein (N) and spike (S1, S2) direct ex vivo interferon gamma (IFNγ) T cell ELISpot to measure T cell responses. Result: Our study demonstrated a similar magnitude of both binding (N-IgG (74% and 62%), S-RBD IgG (70% and 53%) and neutralizing (D614G (49% and 29%), Delta (56% and 47%), Beta (48% and 24%), Omicron BA1 (41% and 21%)) antibody responses from symptomatic and asymptomatic survivors in Nigeria. A similar magnitude was also seen among vaccinated participants. Interestingly, we revealed the presence of preexisting binding antibodies (N-IgG (60%) and S-RBD IgG (44%)) but no neutralizing antibodies from samples collected prior to the pandemic. Discussion: These findings revealed that both vaccinated, non-vaccinated and convalescent individuals in Southern Nigeria make similar magnitude of both binding and cross-reactive neutralizing antibody responses. It supported the presence of preexisting binding antibody responses among some Nigerians prior to the COVID-19 pandemic. Lastly, hybrid immunity and heterologous vaccine boosting induced the strongest binding and broadly neutralizing antibody responses compared to vaccine or infection-acquired immunity alone

MATHEMATICAL MODELLING OF THIN LAYER SOLAR DRYING OF IGHU

A solar cabinet dryer was fabricated and used in evaluating thin layer drying of Ighu.  Three air-plenums (40mm, 60mm, 80mm), three loading densities (330g/mm2, 530g/mm2, 730g/mm2) and three moisture contents (57.8%, 67.3%, 75.6%) were applied to the process of drying to determine their effects on drying time. Fresh Ighu samples were prepared and dried by a natural open sun drying method. The experimental moisture ratios of the samples were fitted to nine drying models. The mathematical models were tested with the drying behaviour of Ighu in the solar dryer and open sun. The Page model and modified Page model were the best model based on statistical parameters of coefficient of determination, root mean square error and reduced mean square errors. They are applicable to predict moisture content of Ighu samples during solar and open sun drying

Efficiency and productivity of Nigerian Cassava cultivars

No Abstract.Nigeria Agricultural Journal Vol. 37 2006: pp. 53-5

Studies on the optimum minisett sizes for rapid multiplication of Rizga (Plectranthus esculentus), Hausa potato (Selenosterum rotundifolius) and Tumeric (Curcuma longa) in Nigeria

No Abstract.Nigeria Agricultural Journal Vol. 38 2007: pp. 24-3

The association between depression and anxiety and use of oral health services and tooth loss

Objective: The purpose of this study is to examine the associations among depression, anxiety, use of oral health services, and tooth loss. Methods: Data were analysed for 80 486 noninstitutionalized adults in 16 states who participated in the 2008 Behavioral Risk Factor Surveillance System. Binomial and multinomial logistic regression analyses were used to estimate predicted marginals, adjusted prevalence ratios, adjusted odds ratios (AOR) and their 95% confidence intervals (CI). Results: The unadjusted prevalence for use of oral health services in the past year was 73.1% [standard error (SE), 0.3%]. The unadjusted prevalence by level of tooth loss was 56.1% (SE, 0.4%) for no tooth loss, 29.6% (SE, 0.3%) for 1–5 missing teeth, 9.7% (SE, 0.2%) for 6–31 missing teeth and 4.6% (SE, 0.1%) for total tooth loss. Adults with current depression had a significantly higher prevalence of nonuse of oral health services in the past year than those without this disorder (P \u3c 0.001), after adjustment for age, sex, race ⁄ ethnicity, education, marital status, employment status, adverse health behaviors, chronic conditions, body mass index, assistive technology use and perceived social support. In logistic regression analyses employing tooth loss as a dichotomous outcome (0 versus ≥1) and as a nominal outcome (0 versus 1–5, 6–31, or all), adults with depression and anxiety were more likely to have tooth loss. Adults with current depression, lifetime diagnosed depression and lifetime diagnosed anxiety were significantly more likely to have had at least one tooth removed than those without each of these disorders (P \u3c 0.001 for all), after fully adjusting for evaluated confounders (including use of oral health services). The adjusted odds of being in the 1–5 teeth removed, 6–31 teeth removed, or all teeth removed categories versus 0 teeth removed category were increased for adults with current depression versus those without (AOR = 1.35; 95% CI = 1.14–1.59; AOR = 1.83; 95% CI = 1.51–2.22; and AOR = 1.44; 95% CI = 1.11–1.86, respectively). The adjusted odds of being in the 1–5 teeth removed and 6–31 teeth removed categories versus 0 teeth removed category were also increased for adults with lifetime diagnosed depression or anxiety versus those without each of these disorders. Conclusion: Use of oral health services and tooth loss was associated with depression and anxiety after controlling for multiple confounders