They would be more concerned with contamination caused by feed produced in an industrial setting. There are plenty of things in a brewery that cows should not eat.
Give me an example what you are talking about that could be potentially harmful to cows, let alone humans.
Caustic cleaners, acids, glycol - all not good to eat. Dogfish Head was evacuated last year because of a leaking 300 gallon tank of nitric acid. Are these likely to contaminate spent grains? Certainly not in most cases, but FDA's business is preventing rare events.
Mostly, the rule will require breweries to have a written hazards analysis for spent grain. They'll have to document how they handle and store grain between brewing and delivery to the farmer, what possible hazards exist that could contaminate grain, how they will prevent contamination, and what their procedure will be if contamination occurs.
This regulation covers all manufactured animal food, not just spend grain. Spent grain is a very small blip in the radar of a set of new FDA regulations that cover human food, animal food, produce, and food importers.
FDA’s proposed rule on Current Good Manufacturing Practices (CGMPs) and preventive controls for food for animals focuses on preventing problems in order to improve the safety of these products. The preventive controls provisions of the proposed rule, which are required by the FDA Food Safety Modernization Act, would apply to domestic and imported animal food, including pet food, animal feed, and raw materials and ingredients. Facilities producing animal food would be required to have written plans that identify hazards, specify the steps that will be put in place to minimize or prevent those hazards, identify monitoring procedures and record monitoring results, and specify what actions would be taken to correct problems that arise. The proposed rule would also establish certain Current Good Manufacturing Practices (CGMPs) that specifically address animal food.
The proposed rule would establish for the first time Current Good Manufacturing Practices that specifically address the manufacturing, processing, packing, and holding of animal food. FDA considered it important to establish CGMPs for animal food as prerequisite requirements to ensure that these products are manufactured under conditions and practices that protect against contamination. The proposed rule also would establish Hazard Analysis and Risk-based Preventive Controls for Food for Animals to implement the provisions in section 103 of the FDA Food Safety Modernization Act. The new requirements would be called “Current Good Manufacturing Practice and Hazard Analysis and Risk-Based Preventive Controls for Food for Animals.”
You can read all about it for yourself.http://www.fda.gov/Food/GuidanceRegulation/FSMA/ucm366510.htm
But trust me, FDA is not reading this forum. Submit your comments here.http://www.regulations.gov/#!submitComment;D=FDA-2011-N-0922-0019