I need to know if the applications (contained in the blackberry store) are verified by blackberry before exposing them for downloads in the store.
I want to help you prevent you from having to ask these type of basic answers. I will therefore show how to use Google and search for your answer:
The first link yielded this article
To prevent an Android-style malware overload from happening on its own platform, and to find a big differentiator in the market, BlackBerry has inked a deal with Trend Micro to add security for third-party apps. All existing and new applications submitted to the BlackBerry World storefront will be scanned for potential malicious behavior.
To do that, BlackBerry is integrating Trend Micro’s Mobile Application Reputation Service with its internal, proprietary system for analyzing applications.
"BlackBerry is working with Trend Micro to implement a more robust approach for addressing privacy and security concerns related to third-party applications," said Adrian Stone, director of BlackBerry security response and threat analysis, in a statement. "By incorporating Trend Micro's advanced mobile scanning and detection capabilities with our own internal, proprietary application analyzing system, we can provide another layer of protection and assurance for BlackBerry customers.”
"The volume of malicious and high-risk mobile apps is on the rise across the industry,” said Kevin Simzer, vice president of corporate development and alliances at Trend Micro. "With the speed that cybercriminals are targeting new platforms and applications, Trend Micro and BlackBerry's strategic collaboration is natural and timely for the security of end users. Together, the two companies can further secure and enhance BlackBerry customers' mobile experience."