浏览器试图下载PHP文件而不是运行它们（Linux Mint，Apache2）

I already disabled

php_admin_flag engine Off

in /etc/apache2/mods-enabled/php.conf and still PHP files won't work. I've encountered similar problem with SWF files already and the cause was in mime-types. So I suspect that current problem may be related. Still, I don't know how to change mime-type for .php?