Eee...blog spam is raging online and sites are getting so badly hacked that you could lose control of your website--not to mention whatever income you have coming off of your business blog website.
Obviously, you need a good anti-spam software as a first step. (Askimet is an easy-to-install WordPress Plugin.)
As a second step, you should be assessing every comment posted on your blog before it's posted. Why? Because spammers are constantly trying to get around anti-spam software. The best way to fully protect your business blog is to be weary of all incoming business blog comments.

BEWARE the spammers who are tricking anti-spam filters...

Now spammers are creating a string of seemingly-genuine comments. If you don't read the comment carefully, you might think it's genuine...and you might approve it. But unbeknownst to you, you've probably just allowed a very bad spammer unrestricted access to some of your best IP: your business blog.
One way you can pick a good comment from a spam comment is the generic nature of the comment. Unless someone is actually responding to particular points of your article, don't allow their blog comment on your site. Something like,  "Hey, really interesting points. The article took me some time to read, but I liked your idea" is too generic to be a real person. It's the sure sign of a spammer, so make sure you label these type of comments "spam" and finish them off by "deleting permanently."
Next post, we'll look at "Why are spammers so interested in posting comments on your blog?"
Not sure if a blog comment is authentic? Ask Tangible Words for a second opinion.

Ps. Don't have a business blog? How to plan your business blog content.