The commentary was a bit incomplete, missing four significant points.
1.  Norovirus is also spread through the air, so that any gathering of 
people, however clean the cooks' hands, is subject to an outbreak. All a 
person needs to do is walk through a droplet cloud left after someone just 
vomited, and s/he can become the next victim, e.g., in a restroom.  No food 
handling needed.
2.  Colleges and universities are an increasingly important outbreak venue 
about which very little has been heard in previous years.
3.  Foodworkers are even more significant sources than previously thought 
just a few years ago because, while most return to work as soon as symptoms 
stop and they feel better, they can continue to spread virus particles for 
up to 72 hours after vomiting stops.  After all, for most workers in the 
private sector the reality is: no work, no pay.
4.  Immunity following an attack is short-lived, in most cases only 6 months 
or so.  Thus, a constantly renewing reservoir of new victims waiting to be 
infected is continually being created.

Charles Easterberg, Lecturer
University of Washington