Where can I find a published national standard that tells foodservice
operators (in writing) the SAFE/CORRECT TEMPERATURES at which
foodservice outlets (restaurants, cafeterias, fast food, etc.) should
serve hot liquids (coffee, hot tea, cocoa, etc.)to their patrons.

Pepping-ga,

The only national liquid temperature standard I could find related to
a maximum 90 degree temperature for water in pressurized sanitation
systems in restaurants.  Based on my searches, it appears that
specific food preparation & service regulations vary by state.

I did find the following related article which you might find
interesting:

The National Food Safety Database has an article called "Reuse of Food
Packaging: Issues in Food Safety" that details the temperatures at
which various types of food packages/containers, including the
plastics and foams cmomonly used to serve hot beverages, distort.
(This information is about halfway down the page.)

( http://216.239.35.100/search?q=cache:nvmaeZvQDyQC:foodsafety.ifas.ufl.edu/il/il112.htm+%22hot+beverage%22+maximum+temperature+guidelines+OR+requirements&hl=en&ie=UTF-8
)

I hope another researcher provides you with a full answer to your
important question!

Best,
Rebeccam-ga

I think it would help people if you clarified whether you are looking
for voluntary or mandatory standards, whether you are focused on
beverages or are also interested in other foods such as nacho cheese,
movie theater "butter", or hot fudge, and whether you are looking for
safe maximum or minimum temperatures (or both). Also, clarifying that
you are looking for U.S. standards (or specifying a nation) probably
wouldn't hurt. If your question is location-specific (i.e., what are
the regulations applying to a particular cup of coffee spilled on a
particular woman's lap at a particular McDonald's restaurant), you can
probably maximize the relevance of your answer by specifying the
location. As rebeccam indicated, there may be variation of standards
down to the local level.

Having been in the food service industry for a while - I have always
been told that there were no specific standards ( in my area at least)
provided that the item was not a dairy, meat, poultry, or fish
product.
Coffee, tea, soft drinks and such were not particularly likely to
develop bacteria or other organisms if kept at room temperature, but
serving a cold cup of coffee was not very good for the repeat
business!!!
A note though - a number of years ago McDonalds was succesfully sued
by a lady for serving a cup of coffee that was too hot!

Throwing my lot in with bobthedispatcher - as a veteran waitress (more
than 10 years in the biz), I found that no two restaurants had the
same standard for coffee/tea/hot chocolate.

Health department inspectors never tested these things, either.  If it
wasn't meat, dairy or a buffet line item, the thermometer never went
near it.

This is not to say that a standard would be a bad idea - many industry
workers have complained of the need for one, especially in the wake of
high profile injury cases such as the one bobthedispatcher noted. 
There just isn't one yet - at least, none I've ever seen or heard of.

--Missy