Trojan: Seek and Destroy

I have been using a flash drive to pass items back and forth from my macbook and my company pc, neither had reported any warnings of a virus or spyware, but when I let a co-worker borrow the stick his pc said that it had blocked a trojan coming from the drive. Is there any way with out downloading/purchasing some type of virus or spyware program to search for trojans on my macbook?

If you can get the trojan name off your friend, then google it.

As it stands NOW there are 2 trojans out there and they are on Suspect Downloaded Software. So unless you have done that there should be no means to worry yourself. And there is no virus out there to muck your Mac up either
Save you money and time and just enjoy your Mac

Cheers
And check this out .. The Official Mac AntiVirus and Firewall FAQ
Even though the thread is old it still pertains to today ...

What kind of software do you have on the stick? Sometime completely legitimate software can be flagged by AV software simply because it was created using similar tools to what virus writers use. If you take MS paint and attach an installer to it (I forget the name of the program that does it) most av suites will tell you paint has a virus.. funny little thing.