Hopefully this is a one off occurrence.
It has to be a task to keep critters out of huge stockpiles of grains and such
Well, considering the 2006 peanut butter outbreak, the spinach outbreak last year followed by the FDA destroying the tomato industry when it wasn't even the tomatoes (it was peppers), "one off" doesn't quite describe it. It's just something that happens when corners are cut.
There are reasons that food processing plants have sanitation standards and QC testing in place. It's when people take shortcuts to save money, or time, or make quota, etc., that things like this happen. You can't be too careful when you make a product that people put into their bodies, whether it's food, nutritional supplements, drugs, or medical devices. It's truly a case of "better safe than sorry."