Occurrence and exposure to glyphosate present in bread and flour products in Lebanon

Glyphosate, a broad-spectrum herbicide, is globally used in crop production and persists in bread and flour. Tolerance limits for glyphosate in cereal products have been established internationally. In Lebanon, there are scarce published data on the level of glyphosate food products and consumer exposure levels remains unknown. All bread and flour products available (n = 164 samples) characterized by their distinct processing methods have been collected from Mount Lebanon and Beirut governorates. Glyphosate concentrations were assessed, using ELISA and compared across samples by brand, flour types and country of origin. The exposure level of the Lebanese population to glyphosate was also assessed through estimated daily intake calculations. Out of the assessed bread products and of flour products tested 80% and 100% were contaminated with glyphosate. All the values were below the international limits (30 mg/kg for bread and 0.5 mg/kg for flour). The glyphosate median residue level was significantly higher in unconventional bread (52.9 ppb), as compared to bran (28.5 ppb) and whole grain (25.7 ppb) and white bread (14.9 ppb) (p = 0.004). Highest percentage positive samples were found for unconventional bread types and lowest for brown bread type (100 and 69.2%, respectively). The findings also showed that glyphosate occurrence and level was statistically identical in all the flour samples including different types and country of origin (p = 0.75, 0.146, respectively). Lebanese population daily exposures to glyphosate through consumption of bread and flour products were estimated to be 0.0702 μg/kg BW/day and 0.1318 μg/kg BW/day, respectively. Daily bread exposure was only 0.000117% of the Acceptable Daily Intake (ADI) of 1 mg/kg/day as listed by Codex, and 0.00039% of the ADI of 0.5 mg/kg/day as listed by the German Federal Institute for Risk Assessment. Dietary exposure to glyphosate through flour and flour-based bread products seems to be low in Lebanon. Future extensive studies need to evaluate exposure to glyphosate from other staple foods and through other routes of exposure beyond diet.