In this internet age, especially with the promotion of Google and Yelp reviews, businesses including professionals are subject to negative comments that are sometimes not based on real facts.

If someone says something that is NOT true, and it damages your business, then you have legal options including a law suit for defamation.  The negative comment cannot be just a negative opinion eg they did not like the quality or type of rice you make.  To be defamation, the intentional comment must use a statement of false facts made with the intent to harm the reputation of your business. 

The law might assume some kinds of harm eg the reputation of a professional is often assumed to be harmed.