You've asked two questions. I'll answer the second first, if you don't mind: how often does a food processing plant need to be monitored for listeria to assess control?
That's actually the subject of a two- or three-day workshop to really get at the answer to that question. But to try to simplify it as much as I can for this purpose, it requires a tremendous amount of data and data analysis and sophisticated pattern recognition and understanding of the unique processing environment in which you're assessing.
One thing we've learned in the industry is that one size doesn't fit all with listeria control. So for one facility we may need x number of samples on a daily basis, yet in another facility it may be significantly more than that.
The plan that was laid out in the new policy that went into effect April 1 represents a level and frequency of sampling that is very appropriate as a starting point for a food manufacturer to feel confident about whether or not that process is under control. At the end of the day, what you're really trying to assess, as a manufacturer, is whether or not that particular line is operating under control. So we use statistical process control techniques, SPC, commonly used in the food industry. We use techniques like that, and other analytical tools, to assess whether or not the process is under control. The only way to do that, as we talked about in the earlier questions, is to have a reliable set of data, and assessing the amount of data that's needed in any one case really requires a look at the historical sampling of that particular line within that particular facility.