There shouldn't be more keywords in the meta tite and description.Like around 3-5 keywords to the max can be added.Also the meta keywords tag is not effective nowadays and google focuses only on the title and meta description tag.
I prefer maximum 3 main keywords in Meta title and description. Using more keywords is keyword stuffing and search engines don't like it. You also should remember limit for title and description shared by arupweb.
Inserting a lot of keywords is as such bad for any SEO activity. For the Title and meta tag, including many keywords would spam your site. So, it is advisable to use not more than 3-4 keywords totally in the title and meta tags.