Securing nginx: Workers per server block under specific user?

[mex]

how do you execute your php? 

if you reverse proxying to an apache you might use suphp, as usual:
http://www.suphp.org/Home.html

php-fpm has a similar option, as alex mentioned


if you really need to define workers for each server, run an nginx-instance
for each of
your websites; you can define an own user for each instance.

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,242209,242444#msg-242444