Theresa Nakoma Ngoma

Theresa Nakoma Ngoma


Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 September 2023 in Journal of the Science of Food and Agriculture
Verified
Journal Article
Open access
TNTheresa Nakoma Ngoma
Theresa Nakoma Ngoma
MMMaurice Monjerezi
Maurice Monjerezi
John LeslieJohn Leslie
John Leslie
BMBrighton Mvumi
Brighton Mvumi
JHJagger Harvey
Jagger Harvey
LMLimbikani Matumba
Limbikani Matumba
Postharvest management is critical to attaining household food, nutrition, and income security. Hermetic grain storage bags offer an effective pesticide‐free way to protect stored grain against fungal and insect infestation. We evaluated articles indexed in the Web of Science that included experiments comparing the storage efficacy of conventional and hermetic storage bags based on grain germination rate, insect infestation, physical damage, mycotoxin contamination, and changes in weight and moisture content. Compared with grain stored in hermetic bags, grain stored in conventional bags lost 3.6‐fold more seed viability, contained 42‐fold more insects, had 11‐fold more physical damage, and lost 23‐fold more grain weight, while grain moisture levels were similar for both hermetic and conventional storage bags. Mycotoxin contamination levels were not as frequently assessed. Levels could be low in grain stored in both types of bags, or levels could be low in hermetic bags and significantly higher in conventional bags. The improved properties of grain stored in hermetic bags can increase food security and household income by providing safe storage options for maintaining seed germinability, and for consumption and/or sale when food supplies are high, or when prices are low. Hermetic bags are economically feasible for use by subsistence farmers in Sub‐Saharan Africa for grain for household consumption and for carrying‐over seed for planting in the next season. Additional studies are needed to verify the mycotoxin contamination results and to determine if there are differences in functional food characteristics, e.g. flavor and cooking properties, that have not been as comprehensively studied. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

3 February 2025 in Sustainability
Verified
Journal Article
Open access
PDF file
TNTheresa Nakoma Ngoma
Theresa Nakoma Ngoma
John LeslieJohn Leslie
John Leslie
SKSamson Katengeza
Samson Katengeza
AGAggrey Pemba Gama
Aggrey Pemba Gama
BMBrighton Mvumi
Brighton Mvumi
LMLimbikani Matumba
Limbikani Matumba
Hermetic grain storage bags are an airtight technology that protects stored grain from environmental factors, pests, and pathogens, with proven feasibility for smallholder farmer use. We examined the determinants and barriers to the use of these bags by smallholder farmers in Malawi and found that 83% of farmers were aware of hermetic bags for grain storage, but only 11–20% had ever used them, with half of the farmers who used the bags receiving them through donations. Furthermore, only 7.2% of farmers used the bags more than once. There was no association between their receipt of donated bags and their continued use and purchase of additional bags. There were, however, strong correlations between use of hermetic bags and the age of the head of household, distance to farmer groups’ meeting points, household size, and participation in a CIP-sponsored project. Focus group discussions identified key barriers to adopting hermetic bags, including local unavailability, perceived high cost, limited knowledge of the technology, low yields, and misconceptions about the utility of the bags. Thus, while donations play a central role in introducing hermetic bags, donations alone are insufficient in ensuring their long-term adoption. Addressing the identified barriers through improved availability, reduced costs, local manufacturing, and policy interventions such as microfinancing options and better distribution networks are essential to increasing the uptake of hermetic bags by smallholder farmers in Malawi and elsewhere in sub-Saharan Africa.

3 October 2024 in Sustainability
Verified
Journal Article
Open access
PDF file
SNSmith Nkhata
Smith Nkhata
FWFinason Watson
Finason Watson
MCMonica Chimbaza
Monica Chimbaza
SNSydney Namaumbo
Sydney Namaumbo
KKKondwani Kammwamba
Kondwani Kammwamba
LMLimbikani Matumba
Limbikani Matumba
The successful translation of biofortified orange maize (BOM) to a staple household food is dependent on farmers’ ability to cultivate and subsequently utilize it. In this study, we assessed farmers’ allocation of their land to the cultivation of BOM and conventional white maize (CWM) varieties in districts where the AFIKEPO Nutrition Program is implemented in Malawi. The results showed that farmers were skeptical of allocating more land to the cultivation of BOM. CWM was allocated significantly more land (1.75 ± 0.51 acres) than BOM (1.12 ± 0.32 acres) (p < 0.001) in all districts. More farmers (87.9%) allocated less than 1 acre to BOM cultivation. The cost of seeds did not explain the preference for CWM, as the price of seeds in Malawi Kwacha was similar for both maize types (p = 0.742). Consequently, the average number of bags (50 kg maize grains/bag) harvested was significantly lower (mean: 6.48 ± 8.27 bags; median: 4 bags) for BOM than for CWM (mean: 23.11 ± 20.54 bags; median: 17 bags). Interestingly, BOM was found to be more resistant to weevils during post-harvest storage, suggesting the potential for improved food and nutrition security for households. The knowledge of high grain resistance to weevils did not influence farmers to cultivate more BOM. This has the potential to negatively affect maize biofortification as an effective strategy to alleviate vitamin A deficiency (VAD) in developing countries. Farmers should be sensitized to identify the benefits of BOM so that they are willing to purchase seeds and grow BOM on a larger scale. Coupled with its higher resistance to storage weevils, superior taste, and nutrient content, the continued cultivation and consumption of BOM has the potential to contribute to the achievement of both food and nutrition security within communities.

27 May 2026 in Plants
Verified
Journal Article
Open access
PDF file
TDTrust Kasambala Donga
Trust Kasambala Donga
TNTheresa Nakoma Ngoma
Theresa Nakoma Ngoma
LMLimbikani Matumba
Limbikani Matumba
JBJames Bokosi
James Bokosi
Maize (Zea mays) production in Africa has been severely constrained by the fall armyworm (FAW), Spodoptera frugiperda, since the pest was first detected on the continent in 2016. Botanical pesticides are increasingly promoted as low-cost alternatives to synthetic insecticides, but the African evidence base remains scattered across plant species, formulations, experimental settings, and outcome measures. This study was conducted as a structured narrative review with an evidence-informed SWOT (strengths, weaknesses, opportunities, and threats) synthesis to evaluate the efficacy, field relevance, and practical limitations of botanical pesticides used against FAW in African maize systems. Literature published between 2016 and 2026 was identified through structured searches of Google Scholar and PubMed and was synthesized narratively because substantial heterogeneity in botanicals, extraction methods, doses, application methods, target stages, and study settings precluded meta-analysis. The review shows that Azadirachta indica currently has the strongest balance of laboratory-to-field support, while Tephrosia vogelii and Nicotiana tabacum remain promising but with conditional options because of chemotype dependence and phytotoxicity concerns. Essential oils expand the mechanistic scope of the evidence base but are still limited by volatility, weak persistence, and comparatively few field validations in African maize systems. Overall, botanical pesticides have credible potential within smallholder-oriented integrated pest management, but require standardisation, better field validation and clearer biosafety evidence, and more accessible formulations are needed before broad recommendation can be justified.

15 May 2024 in Preprints.org
Verified
Preprint
Open access
PDF file
TNTheresa Nakoma Ngoma
Theresa Nakoma Ngoma
VTVictor Taleon
Victor Taleon
BMBrighton Mvumi
Brighton Mvumi
AGAggrey Pemba Gama
Aggrey Pemba Gama
NPNatalia Palacios-Rojas
Natalia Palacios-Rojas
LMLimbikani Matumba
Limbikani Matumba
Maize is the staple cereal in Malawi, with a daily per capita consumption of 383g (dry matter basis), primarily consumed as dehulled maize flour used to cook nsima, a thick porridge. However, the extent of mass and nutrient loss during dehulling remains unclear in this food-insecure country, where the household maize harvest typically lasts only 6–7 months. In the current study, a milling experiment to determine yield and micronutrient losses was conducted. Milling batches (30 kg) of four maize grain varieties were dehulled at three abrasive disk dehullers under controlled conditions. Mass losses ranged from 18.8% to 42.7%, with a mean of 28.2±5.7%. Maize variety and dehuller significantly affected mass loss (p<0.05). Initial protein, iron, and zinc concentrations were 8.8 ±1.0 g/100g, 20.5±2.0 µg/g, and 18.2 ±2.6 µg/g, respectively. Post-dehulling nutrient true retention varied for protein (49.7% to 75.6%, mean=64.7±7.0%), iron (18.7% to 71.6%, mean=37.6±12.0 %), and zinc (11.0% to 46.2%, mean=27.9±8.7 %). Maize variety significantly influenced mass and protein loss (p < 0.05), while dehuller influenced mass, iron, and zinc losses. However, no significant difference (p > 0.05) was found in the interaction between dehullers and variety on mass and nutrient losses, respectively. Given Malawi's precarious food insecurity situation, transitioning from dehulled maize flour nsima to whole maize flour or less refined nsima, is imperative. Our study findings can have food and nutritional savings for other southern Africa countries where the dehulling practice is rampant.