Table 1.
Summary of approved active ingredients for cocoa production.
These pesticides are recommended for cocoa cultivation in major cocoa producing countries in West Africa which account for 70% of the World’s cocoa.
Fig 1.
Procedure followed to select studies for inclusion in this systematic literature review.
Numbers presented are from the first search of the literature in November 2020 only, while results from the supplementary search in November 2022 are given in S1 Fig. The "eligibility" box covers both the eligibility screen and quality assessment. Based on PRISMA flow chart [45].
Table 2.
Type of data extracted from included articles.
Based on this, a customised data extraction form was developed and used for data capture and processing.
Fig 2.
The year and country where existing studies were conducted.
The studies were published over 25 years across 35 countries. Above) Non-cocoa growing countries where studies were conducted. Below) Cocoa producing countries where studies took place. Overall, 18 studies were conducted in eight cocoa growing countries.
Fig 3.
Geographical spread of the studies that were undertaken (grey areas = no studies).
Spain (15 studies), China (15 studies) and Italy (10 studies) were the top three countries with most studies. One study each was conducted in Ivory Coast and Ghana, which are the first and second ranked cocoa producing counties in the world, respectively. [Credit: [48]].
Fig 4.
The 57 cocoa producing countries in the world based on the metric tons of cocoa produced annually.
Ivory Coast is ranked first with 2,034,000 metric tons of annual production. 19% of the included studies evaluated in this review took place in eight cocoa producing countries. Grey areas = non-cocoa producing areas. Map developed using [48] and data sourced from [49].
Fig 5.
Heatmaps with colour scale on the right of each graph showing the detected: A) organochlorines and organophosphates B) neonicotinoids and pyrethroids; C) fungicides and herbicides, and D) acaricides other pesticides which were studied (x-axis) over the period and the respective countries where detections took place (y-axis). Concentrations of each detected pesticide were averaged per the number of detections per country to get one value for each pesticide detected. Units for all detected pesticides were standardised by converting to mg/kg. The individual graphs can be referred to in S2–S5 Figs.
Fig 6.
The frequency of detection of the different classes of pesticide residues in the 20 studies conducted in six cocoa growing countries: Ghana, Ivory Coast, Brazil, Mexico, India, and Pakistan.
No pesticide residues were detected in studies conducted in Thailand and Uganda, the other two cocoa growing countries where studies took place.
Table 3.
Concentrations of pesticide residues exceeded the maximum residue limits specified by the European Union by 2022.
Those in bold denote pesticide residues that exceed the previous and revised MRLs. Asterisks denote concentrations that were thought to have exceeded the previous MRL established by the EU in 2005. These concentrations, however, are below the updated MRL that the EU has set as of 2022.