Food safety training and rating programs for informal processed food markets in Northern Ghana

Last registered on October 14, 2022


Trial Information

General Information

Food safety training and rating programs for informal processed food markets in Northern Ghana
Initial registration date
July 16, 2022

Initial registration date is when the trial was registered.

It corresponds to when the registration was submitted to the Registry to be reviewed for publication.

First published
July 21, 2022, 11:37 AM EDT

First published corresponds to when the trial was first made public on the Registry after being reviewed.

Last updated
October 14, 2022, 11:02 AM EDT

Last updated is the most recent time when changes to the trial's registration were published.


Primary Investigator

Colorado State University

Other Primary Investigator(s)

PI Affiliation
International Food Policy Research Institute
PI Affiliation
University for Development Studies
PI Affiliation
University of Georgia

Additional Trial Information

In development
Start date
End date
Secondary IDs
Prior work
This trial does not extend or rely on any prior RCTs.
Most food consumed in developing countries is transacted in informal markets. While these markets provide an important source of low cost food for the poor, they can also present food safety hazards. In Ghana and throughout West Africa, kulikuli is a popular snack food made from groundnuts. Because kulikuli is fried and spiced, it hides the morphology and taste of groundnuts likely to be contaminated with aflatoxin. Thus, poor quality and potentially hazard groundnuts (also traded informally) frequently end up in kulikuli. In this study we implement and evaluate a training program to teach kulikuli producers how to avoid and sort out potentially hazardous groundnuts before making kulikuli. As part of the program, we will test and rate producers' kulikuli and provide marketing materials for producers to signal that they have been trained and the safety of their kulikuli. The program will be complemented by an information intervention targeting local consumers. To evaluate the intervention we will conduct a market-level cluster randomized control trial with 720 kulikuli producers and 1440 consumers. We will evaluate the intervention's impact on producer and consumer behavior, as well as on food safety of locally available kulikuli.
External Link(s)

Registration Citation

Hoffmann, Vivian et al. 2022. "Food safety training and rating programs for informal processed food markets in Northern Ghana." AEA RCT Registry. October 14.
Experimental Details


The project has a producer intervention and consumer intervention. The producer intervention has three components: training, testing, and rating. Producers will be invited to attend a training on using safe groundnuts to produce kulikuli. Upon completion of training they will receive a prominent sign to post at their point of sale stating they have completed the safe kulikuli production training. Testing will occur every two weeks using a sample purchased by a mystery shopper. Based on the test results, the producer will earn a rating, which they can post on their sign in a designated spot. The consumer training will involve telling nearby consumers about aflatoxin, the high risk of aflatoxin in kulikuli, how to find and identify producers trained on aflatoxin prevention, and how to interpret the rating system to make sure the producer has recently received a satisfactory rating.
Intervention Start Date
Intervention End Date

Primary Outcomes

Primary Outcomes (end points)
Producer outcomes: aflatoxin awareness, time spent sorting bad nuts out, quantity of bad nuts sorted out, quantity of kulikuli produced, quantity of kulikuli sold, aflatoxin levels in kulikuli.

Consumer outcomes: Criteria for selecting kulikuli, aflatoxin/food safety knowledge, knowledge of training and rating program
Primary Outcomes (explanation)
See pre-analysis plan for more details.

Secondary Outcomes

Secondary Outcomes (end points)
Producer outcomes: Source of groundnut stock, price paid for groundnut stock, price of kulikuli sold, quantity of kulikuli consumed at home.
Consumer outcomes: Perceives there to be a quality difference between vendors, quantity of kulikuli purchased, price paid, youngest kulikuli consumer in household
Secondary Outcomes (explanation)
See pre-analysis plan for more details.

Experimental Design

Experimental Design
First, we will randomize our interventions at the market cluster level. Treatment clusters will receive both the producer and consumer intervention, and control clusters will receive no intervention whatsoever.

Next, we will randomize recruitment into the producer intervention within clusters. In treated market clusters, we will randomly select half of the producers to invite to the training, testing, and certification program. The other half will be invited at the end of the study. This will allow us to test for effects on certified and non-certified producers, who may be affected through information spillovers, shifts in consumer preferences, or changing prices. Furthermore, offering these producers training and certification later will allow us to measure demand for certification not directly incited by the research team (see below) and reduce the potential of harming initially non-certified producers or causing conflict between producers. In control clusters, we will randomly select half of the producers to be in the study so that we have three equally sized treatment arms: 240 treated producers, 240 untreated producers in treated market clusters, and 240 control producers.

We will stratify the randomization across market clusters based on geography and the number of producers in the cluster. We believe geography will be the best determinant of where a producer sources their groundnuts, which is they factor we believe will be most highly correlated with aflatoxin levels. Stratifying based on the number of producers will help us get the same number of producers in the three treatment arms. Because we will only stratify on these variables, we can assign treatment before collecting baseline data, which has two advantages. First, it allows us to construct a sample with an average of 12 producers in treatment market clusters (half of whom will be treated) and an average of six producers in control clusters. Second, it makes it possible to invite (treatment) producers to training upon completion of the baseline survey.

Coinciding with producer training, we will implement the consumer intervention in all treated market clusters. This means we will estimate the combined effect of a producer and consumer intervention, which we believe is the most likely way a program like this would be implemented in practice. This design does not allow us to estimate the effects of the producer intervention alone, or to estimate the \emph{additional} effect of the consumer intervention when the produce intervention is in place. However, it gives us maximum power to estimate the (combined) treatment effect we are most interested in.
Experimental Design Details
Not available
Randomization Method
Randomization done in office by a computer.
Randomization Unit
Market cluster (neighborhood) first, then individual vendors within treated market clusters.
Was the treatment clustered?

Experiment Characteristics

Sample size: planned number of clusters
80 market clusters.
Sample size: planned number of observations
720 kulikuli producers, 1440 kulikuli consumers.
Sample size (or number of clusters) by treatment arms
40 market clusters per treatment arm. 240 producers per treatment arm. 480 consumers per treatment arm.
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
Producer outcomes (other than aflatoxin): 0.21 standard deviations. Aflatoxin: 0.25 standard deviations (66% decrease). Consumer outcomes: 0.19 standard deviations.

Institutional Review Boards (IRBs)

IRB Name
University of Georgia Institutional Review Board
IRB Approval Date
IRB Approval Number
IRB Name
University for Development Studies
IRB Approval Date
IRB Approval Number
IRB Name
International Food Policy Research Institute
IRB Approval Date
IRB Approval Number
Analysis Plan

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