Genetically engineered (GE) bacteria have been found in riboflavin vitamin supplements intended for animal feed use according to newly published EU tests.

Contamination of food grade or animal feed supplements with GE bacteria is illegal in the European Union. In 2014, however, a German enforcement laboratory alerted EU officials to illegal GE bacterial contamination of a riboflavin supplement intended for animal feed. Further tests showed that the illegal contaminating strain was not among those the manufacturer claimed to be using.

The findings, just published in the journal Food Chemistry, were made by regulators from Germany and Italy who were sampling Chinese imports (Paracchini et al., 2017).

Riboflavin (vitamin B2) is an essential vitamin of vertebrate organisms. It is commonly used as a food additive for humans and animals. Until quite recently, all riboflavin supplements were chemically synthesised. However, riboflavin is now frequently produced by commercial fermentation using overproducing strains of GE bacteria.

According to EU biosafety regulations, no GMO bacterial strain, nor any DNA, is allowed to be present in commercial supplements. However, the contaminated sample of riboflavin contained viable strains of the genetically modified organism Bacillus subtilis. The researchers cultured and tested the contaminating bacterium and subsequent DNA sequencing showed it to be a production strain.