40 - Fate of Pesticide Residues During Brewing

Abstract

This chapter emphasizes the influence of the different phases of beer-making and the removal of pesticide residues. The effect of their presence on beer quality and health impact is also assessed. With this aim, based on the current data an overview of the behavior and fate of agrochemical residues during the brewing stages (malting, mashing, boiling, fermentation, and stabilization of the beer) is presented. The methodology for analysis of pesticide residues and their metabolites in raw materials, wort, and beer and the main aspects of the food safety and policy in the European Union (EU) are summarized. Depending on the stage involved and the physical–chemical properties (mainly KOW [as log P] value, water solubility, vapor pressure and Henry's law constant) of the residue in the raw materials, differences in the final fate of the residues are observed. As a general rule, the malsters should devote special attention to the residues of hydrophobic pesticides with KOW > 2 because they can remain on the malt. On the contrary, brewers should control residues of hydrophilic pesticides with KOW < 4 because they can be carried over into beer. Thus, the monitoring and surveillance of pesticide residues with KOW ranging from 2 to 4 (most of them) during the brewing process is essential to get a “healthy drink.” Additionally, the influence of pesticide residues on flavor, sugar content, acidity, color or total polyphenol, and flavonoid contents has been pointed out. Therefore, the knowledge of the behavior of pesticide residues must be intended to (i) provide information on the transfers of residues from barley to malt, wort, and beer to calculate concentration or reduction factors during each process; (ii) achieve a realistic estimate of the dietary intake of pesticide residues; (iii) propose maximum residue limits (MRLs) for residues in beer when necessary; and (iv) avoid alterations in the beer quality.