Vegetables and fruits in Brazil, Estonia, and Taiwan have more nitrates and nitrites than in other countries, with Brazil having the most—this suggests that where you grow your produce can affect how much of these chemicals are in it.

Measures nitrate/nitrite concentrations in vegetables and fruits from randomly selected markets and farms in Brazil, Estonia, Taiwan, and at least 10 other countries using identical lab protocols, with sample sizes proportional to population and agricultural output, to determine if these three countries have statistically significantly higher mean concentrations.

Aggregates all peer-reviewed, methodologically consistent measurements of nitrate/nitrite in produce from Brazil, Estonia, and Taiwan, comparing them to equivalent data from other nations to confirm if these three consistently rank highest across multiple independent studies.

Compares nitrate/nitrite levels in produce from Brazil, Estonia, and Taiwan (cases) with levels from matched regions with lower reported levels (controls), controlling for crop type, season, and farming practices to isolate geographic factors.

Analyzes publicly available government or regulatory agency reports on pesticide and contaminant levels in produce to verify if Brazil, Estonia, and Taiwan consistently report the highest nitrate/nitrite levels in official datasets.

Gathers expert consensus from agricultural scientists and food safety regulators in each country to assess whether Brazil, Estonia, and Taiwan are perceived as having the highest nitrate/nitrite contamination in produce.