How many 301s in htaccess is too many?

My htaccess file has over one hundred 301 redirects in it (I've just reworked the entire site).
Will this amount of 301s slow down my site?

 

There's no pattern to the urls (osCommerce > Wordpress), so there's not really any other way to do it...
e.g

Redirect 301 /shopping-lipstick-p-102.html http://www.domain.com/lipstick.html
Redirect 301 /dining-cutlery-p-24.html http://www.domain.com/knives-forks.html
Redirect 301 /fashion-shoes-p-105.html http://www.domain.com/shoes.html

Code (markup):

I've already spent all morning manually entering the 301s into htaccess anyway (what a task!), and it's working nicely.
I was just concerned that having heaps of 301s might slow down page loads, or might just be "not the done thing".