If you are finding a lot of spam in your product reviews, please check whether you have enabled (ticked) Auto Confirmation in your Product Review settings section of your Admin Panel. Enabling Auto Confirmation means that all reviews are approved and no pending reviews appear in your Product Review section. To prevent this, disable (untick) Auto Confirmation. Remember to periodically revisit the panel to determine which reviews to approve.
If you find a spam review, you can also simply delete it from the reviews list in your admin panel.
