There is a product called Metascan that provides an API in Java and COM that supports scan and related features of several McAfee products.
The list of applications supported by the API is at http://www.opswat.com/products/metascan/supported-applications
Free evaluation of the Metascan can be obtained by filling the form at http://static.opswat.com/metascan_eval.shtml
I have used Metascan with success as well. By the way, it comes in 3 versions: Core (which integrates with existing, licensed AV), Lite (has 3 licensed engines and also integrates with existing engines) and Ultra (which has 8 licensed engines and also integrates the pre-installed engines). Metascan also has remote client capabilities which helps scaleability. OSPWAT (makers of Metascan) also offer other multiscanning solutions like MetaDefender for Media and MetaDefender for Secure Access.