About HarvestPlus

HarvestPlus improves nutrition and public health by developing and promoting biofortified food crops that are rich in vitamins and minerals and providing global leadership on biofortification evidence and technology. HarvestPlus works across CGIAR as part of the Innovation Policy and Scaling Unit of the International Food Policy Research Institute (IFPRI).

Background

Because staple crops are the backbone of food systems, and relied upon for food security, successful genetic gains in these crops have vast potential to strengthen the resilience of food systems to deliver nutritious foods sustainably and consistently. Climate-resilient, biofortified crop varieties are acknowledged internationally (SOFI 2021) as cost-effective food supply interventions to reduce micronutrient deficiencies while increasing the availability and access to nutritious foods for a significant proportion of the 3 billion people who cannot afford a healthy diet. To help vulnerable communities to respond to and to prepare for future impacts of climate change, HarvestPlus scales access to biofortified crops along with training and capacity building for sustainable land and water management including conservation agriculture techniques that increase crop resilience. Breeding biofortified crops protects and improves genetic resources for crop variety diversity and dietary nutrient density. Biofortified varieties are bred to be high yielding, with non-negotiable agronomic traits like biotic disease, and abiotic stress resistance (as drought and heat tolerance) that are tested by national agricultural research institutions under local agroecological conditions. When possible, crops are developed to be early maturing, contributing to soil health and improving time use for farmers, who are often women. Due to high yields of biofortified varieties and HarvestPlus’ market systems facilitation, these crops should improve economic returns to farmers, including women and female headed households.

HarvestPlus’ goal is for biofortified varieties to replace less resilient non-biofortified varieties, not to decrease crop diversity through monocropping. Land allocated to vegetables and fruits, leafy greens and other food perishable food crops do not change.

Maize biofortified with provitamin A carotenoids

Similarly to preformed vitamin A added to foods in large scale food fortification, provitamin A carotenoids in biofortified maize, cassava and orange sweet potato (OSP) break down when the food is processed and stored for relatively long periods of time. Natural decay notwithstanding, regular consumption of crops biofortified with provitamin A carotenoids (pVAC) significantly improves vitamin A status, immune defense and improves night vision among multiple age groups and across geographies without the potential risk of hypervitaminosis that could be associated with excessive intake of preformed vitamin A (e.g., multiple foods fortified with retinol palmitate). Moreover, the impact of the additional pVAC from consumption of biofortified foods had the greatest impact on those with poorer vitamin A status.

The visible yellow-orange color associated with pVAC crops, does not affect farmer adoption and consumer acceptance. In Zambia, a monitoring survey conducted in 2015 confirmed a strong preference by farmers for both the production and consumption attributes of vitamin A maize varieties compared with conventional white maize varieties. Nearly all farmers (97 percent) who participated in the study said that they would grow vitamin A maize (VAM) in the next season, and on average, farmers were planning to plant four times more seed than they did in the previous (2014–2015) season. Another monitoring survey conducted in 2017 found that almost all the farming households who had acquired VAM seed did plant it, and 87 percent of the harvest was kept for home consumption. The survey also showed that 44 percent of the VAM growers also purchased more from the market, showing that adopting households liked VAM. In rural Zambia, consumers valued nshima (maize porridge) made with VAM more than nshima from white and yellow maize varieties, even in the absence of nutrition information. Nutrition information increased consumer valuation of VAM. Similarly in Malawi, there was high acceptability of porridge prepared with VAM among caregivers and children.

Food Safety - Aflatoxins and Fumonisins

The potential for scaling up biofortified crops is reliant in part on farmers', consumers', and value chain actors' acceptance of biofortified crops. Food safety is also a prerequisite to food and nutritional security and an essential component of food systems.

Aflatoxins and fumonisins (some of the most common toxic fungal metabolites, also known as mycotoxins) are fungal toxins that possess acute life-threatening toxicity at any stage of life, carcinogenic properties and other potential chronic adverse effects. When mycotoxins contaminate foods, they cannot be destroyed by normal cooking processes. Aflatoxin exposure is a major risk factor for liver carcinoma and may be a determinant of growth stunting in children and increasing disease susceptibility due to lower immune defenses. Further research is needed to assess causality between aflatoxin exposure and linear growth and immunity effects.
In Africa, aflatoxins pose major risks to human and animal health, nutrition, as well as intraregional and international trade. Contamination of African staple foods is a major issue for human and animal health, nutrition, and trade. For maize, all African studies indicate mean aflatoxin B1 (AFB1) levels to exceed the legal limit established by the European Union and other national guidelines. Studies on contamination levels and biomarkers consistently demonstrate that overall exposure is high, leading hypothetically to a substantial increase in long-term disease burden. In addition, concentrations in food occasionally can reach very high levels, causing acute aflatoxicoses. Nonetheless, recent developments in aflatoxin and fumonisins exposure biomarkers may be seized upon to elucidate important food safety and epidemiological data for crop development.

Humans can be highly exposed to mycotoxins due to their cereal-based diets and are particularly susceptible to mycotoxins. Human exposure of aflatoxins and fumonisins is mainly through the ingestion route, but limited amounts of aflatoxins may also enter through inhalation or through the skin and mucosae. Exposure assessment is a key for epidemiological assessment of the effect of aflatoxin on human health and the determination of the associated risk to public health. The most popular tool is food analysis, which unfortunately does not include individual exposure and should therefore be accompanied by analysis of serum or/and urine samples. Among the >20 known aflatoxins, the four main ones are AFB1, aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), and aflatoxin G2 (AFG2 (Inan et al., 2007). Fumonisins B1, B2, and B3 comprise most of the grain contaminated with this mycotoxin in African countries (Yli-Mattila T and L Sundheim, 2022)

Based on limited evidence it is plausible to conjecture that carotenoids in VAM and pumpkin varieties can inhibit the synthesis of Aflatoxin B1 (AFB1) in field and lab conditions. (Savignac JM et al J Ag Food Chem 2023; Suwarno WB et al Front Plant Sci 2019; Norton RA, 1997; Mboup M et al Crop Prot 2024; Mollel, et al., Sci Afric 2025; Alonso-Garrido M et al Arh Hig Rada Toksikol 2021).

Aflatoxin exposure assessment may be performed in biological samples, i.e., blood/plasma/serum, in urine, or in breast milk, or estimated from analysis of the dietary intake of aflatoxins. The assessment of mycotoxin exposure in humans has been reviewed by Al-Jaal BA et al (Food Chem Toxicol 2019. doi: 10.1016/j.fct.2019.04.047. Epub 2019 Apr 26) and Srinivasan B, 2021.

Objective of the RFP - Consultant Role

This study will provide a comparative assessment of exposure to mycotoxins derived from contaminated maize consumption in communities consuming vitamin A maize and white maize under similar harvesting, grain storage and milling practices.

The varieties for evaluation should be selected in consultation with the IFPRI project manager.

The study responsibilities under the research center/consultant include the following:

1. Review of varieties and provitamin A carotenoid contents available and are being used in-country and proposed study site(s), in collaboration with relevant partners. Ensure that information about crop maturity (early/late), grain hardness and other relevant traits is collected.
2. Identification of high-risk population groups (documented contamination with mycotoxins, high maize consumption, maize milling practices and other sources of exposure and relevant exposure mitigation interventions, etc.) via the NARS and available public health and agronomic data to establish VAM variety penetration in mycotoxin prone areas.
3. This study is intended to be a cross-sectional exploration of what communities are already consuming and the exposure to mycotoxins derived from the white vs orange maize used. If there are no VAM varieties being grown and consumed in accessible sites, the consultant/center will perform oversight of growing, harvesting, storage (under optimal and common suboptimal conditions) and utilization of the selected VAM variety(ies) and collection of representative samples for physical, biochemical and toxicological characterization of the grain for both white and VAM maize.
4. Serial cross-sectional assessments of exposure to AFL1 and other mycotoxins with diagnostic value (high sensitivity and specificity) as indicators of exposure, preferably obtained in a noninvasive manner (e.g., urine samples normalized with creatinine or specific gravity) and controlling for potential co-contaminants (pesticides, heavy metals, etc.) and other sources of mycotoxins as well as pre- and post-harvest methods of mitigation present in the study areas.

Note: To support the study, HarvestPlus/IFPRI may concurrently lead experimental maize multiplication and laboratory research activities on in vitro maize provitamin A carotenoids and mycotoxins (pending complementarity to the study proposal).

Study Deliverables

Outputs from the findings of this study will be shared with national stakeholders and donors to inform maize breeders and policy makers of the varieties and postharvest practices that warrant further investment and improvement to safeguard health among maize-consuming populations.

1. Study tools (survey questionnaires, laboratory samples quality control and tracking, and results forms, relevant ambient contamination records, etc.)
2. High quality data set(s), in format suitable for posting to IFPRI Dataverse
3. Debrief on findings with HarvestPlus
4. Technical report, including detailed methodology, findings, conclusions, and recommendations. Publishable manuscripts are preferred.

Study Timeline

1. Expected start of contract: August 2025
2. Duration of study: August 2025 – February 2026 (7 months)
3. Deliverables submitted: March 2026

Proposal

A research protocol (proposal) should be submitted as an attachment to a standard work plan and budget template (which will be provided by HarvestPlus/IFPRI) upon receipt of the principal investigator’s expression of intent to apply by email.

The proposal should consider:

Ethics
It will be the responsibility of the principal investigator to obtain approval of the appropriate ethics committee or institutional review board (IRB) prior to the initiation of any contact with study subjects. The IRB process will be required before the awarding of the contract is completed. Funds will not be advanced until the IRB approval letter has been submitted, except for preparatory activities that do not involve research with humans, in which case an initial advance may be disbursed.

Local Partner (if applicable)
The local partner should be a well-established legal entity in the country where the study will take place who may form partnerships and/or a consortium with other entities within or outside the country to provide the necessary expertise and resources to carry out the project. HarvestPlus will contract directly with the lead institution in a consortium or partnership and that institution will be responsible for the dealings with the other parties. The recipient institutions must submit copies of their corporate documents prior to awarding a contract.

Research Group Qualifications
The CVs of each lead researcher (including local partners) shall be submitted with the proposal. The CVs should clearly document the researchers’ qualifications, publications, expertise, and experience in relation to the component(s) of the project that he/she will be responsible for, and references for all relevant peer-reviewed publications. Labor costs should be limited to individuals contributing directly to project design and implementation, analysis and report writing.

Project Study Site(s)
The study site within a Sub-Saharan African country and sites affected by high prevalence and exposure to maize aflatoxins. Strong cases for Uganda, Zimbabwe, Nigeria, Kenya, Malawi, or Tanzania will be considered. Study site selection will be at the discretion of the research team and based on the relevance and magnitude of the stated health problem as well as pre-existing conditions that facilitate the implementation of the study. Site selection will be based on factors such as the existence of control and intervention communities willing to participate in an observational study comparing aflatoxin exposure in VAM and white maize consuming populations.

Other items to be included in the proposal:
Title page with main investigator contacts details
Background information (brief literature review) demonstrating in-dept understanding of the request for proposals and the subject matter of the research under consideration
Study aims and specific objectives
Detailed description of study design and methodology:
• Sample size calculation and statement of assumptions.
• Description of the main and secondary outcomes, sample size calculation for primary and secondary outcomes, study design, sampling design, selection and exclusion of subjects, methodology, ethical considerations and assurances, data management and statistical analysis plan
• Clear study timeline outlining all major milestones and deliverables (as a Gantt chart, or other appropriate format)
• Any other relevant aspects critical for the success of the study such as relevant ongoing studies and available complimentary funding

Application Timeline