Security magazine Virus Bulletin has issued the results of a new test of spam blocking software.

The second edition of the test pitted anti-spam filters against an archived collection of spam messages, and a live stream of email from addresses set up by testers. Products were scored for the percentage of spam messages detected and the number of false positives returned.

Two of the nine products tested earned the highest 'platinum' certification. The top performers were Kaspersky's Anti-Spam 3.0 and Message Architects' M+ Guardian spam blocker.

Giacom's MessageStream service earned a 'gold' certification, while WebRoot's E-Mail Security, FortiMail and BitDefender Security for Mail Servers all earned 'silver' certifications.

Among the worst performers in the test were ClamAV and Spam Assassin. ModusGate also missed out on earning a certification due to a high rate of false positives.

The tests are the second such spam trials from Virus Bulletin, better known for its VB100 anti-malware tests. In the report, the magazine said that the spam testing is beginning to form a clearer picture about the top performers on the anti-spam market.

"It was a relief to see the bugs that had caused some stress during the first test had been solved," they wrote.

"It is also good to see several of the products showing credible results and thus to get a better picture of which products really are the high performers in this field."