In 1978, the United States Brewers Association (USBA) informed the FDA that German researchers had reported finding low levels of dimethylnitrosamine (DMNA) in beer. The FDA and USBA each surveyed beers and other malt beverages available in the United States and reported similar findings. Based on information from the Germans and subsequent investigations by the USBA, it is apparent that DMNA formation occurs principally during the kilning (drying) of sprouted barley used in the production of barley malt. The barley malt is then used in the wort for making beer and other malt beverages.
The level of DMNA formed during kilning varies depending on a number of factors. Studies have shown that higher levels of DMNA are more likely to occur when the malt is kilned by direct fire (open flame) than when indirect fire is used. Various methods for reducing DMNA formation have been investigated, including the introduction of sulfur to the open flame. Although other techniques are under experimentation, the USBA has reported that sulfur is being used during kilning for most barley malt currently produced in the U.S., resulting in substantially lowered levels of DMNA. Consequently, the level of DMNA in beverages produced from those malts also should be substantially reduced.
DMNA has been shown to cause cancer in laboratory animals and a level of safety cannot be established. The agency has determined that it is necessary to minimize human exposure to the lowest practical level. This level was determined to be 5 ppb DMNA, based on the analytical limit and the extent to which DMNA can be reduced in malt beverages by good manufacturing practices. Beverages containing more than 5 ppb DMNA may be considered to be adulterated under section 402 of the Act.
REGULATORY ACTION GUIDANCE:
The following represents criteria for recommending legal action to CFSAN/Office of *Compliance*/Division of Enforcement (HFS-605):
Each of four subsamples contains greater than 5 ppb DMNA and the presence of DMNA is confirmed by mass spectrometry.
NOTE: Refer to Sec. 578.500 (CPG 7104.07) for DMNA in barley malt.
*Material between asterisks is new or revised.*
Revised: 3/95, 8/96, 5/05