Methanol contamination in traditionally fermented alcoholic beverages: the microbial dimension

Abstract

Incidence of methanol contamination of traditionally fermented beverages is increasing globally resulting in the death of several persons. The source of methanol contamination has not been clearly established in most countries. While there were speculations that unscrupulous vendors might have deliberately spiked the beverages with methanol, it is more likely that the methanol might have been produced by contaminating microbes during traditional ethanol fermentation, which is often inoculated spontaneously by mixed microbes, with a potential to produce mixed alcohols. Methanol production in traditionally fermented beverages can be linked to the activities of pectinase producing yeast, fungi and bacteria. This study assessed some traditional fermented beverages and found that some beverages are prone to methanol contamination including cachaca, cholai, agave, arak, plum and grape wines. Possible microbial role in the production of methanol and other volatile congeners in these fermented beverages were discussed. The study concluded by suggesting that contaminated alcoholic beverages be converted for fuel use rather than out rightly banning the age—long traditional alcohol fermentation.

Determination of Volatiles and Carotenoid Degradation Compounds in Red Pepper Fermented by Lactobacillus parabuchneri

“…On the other hand, the contents of methyl esters, which were predominant in this study, were higher than those of ethyl esters. In general, methyl esters can form by the esterification of organic acids and methanol, which is a major product of pectin that is linked to pectin demethylation (Ohimain, 2016). The contents of hydrocarbons in fermented red pepper increased as fermentation proceeded.…”

Twisted-Planar-Twisted expanded porphyrinoid dimer as a rudimentary reaction-based methanol indicator

“…Methanol is a key industrial chemical and a recognized human toxin. It is used as a denaturant in laboratory and industrial-grade ethanol but can also be present in distilled beverages whose quality is not carefully controlled 30 , 31 . Not surprisingly, therefore, considerable effort has been devoted to the problem of sensing methanol in the presence of ethanol and other potentially competing analytes 32 , 33 .…”

Methanol content in homemade alcohol from a province in North Vietnam

“…Distillation of ethanol without temperature control can thus cause methanol to be produced along with ethanol. In addition, the fermentation with microbes can produce methanol .…”