Google is beefing up the way it checks if any of the apps uploaded to its Play store are malicious.
All new apps will be scanned by malware-spotting tools from three cyber-security firms as well as Google's own in-house system.
Google said it needed help because the number of apps being uploaded was too large for it to handle alone.
Nasty Play apps can hit lots of people. Malicious code found in June was in apps downloaded 400 million times.
Security firms Zimperium, Eset and Lookout will partner on what Google has called the App Defense Alliance.
The four partners will set up a combined scanning system that will scrutinise apps as they pass through Google's pipeline on the way to being offered to Android users via the Play store.
Working from massive databases of known malware, behavioural clues and machine-learning models of novel threats the scanners will look for trojans, adware, ransomware, banking malware and phishing attacks.
"On the malware side we haven't really had a way to scale as much as we've wanted to scale," Dave Kleidermacher, Google's vice president of Android security told Wired magazine.
Mr Kleidermacher added that there were so many apps being developed that even making a "one percent incremental improvement" could make a difference.
The scanning system is the latest in a series of steps Google has taken in its bid to do a better job of policing the Play store.
In April it announced more rigorous checks for developers to root out "bad faith" coders who produce and upload malicious or fraudulent apps.