Switch case or if php - sign category

i have a really simple task to do, but i guess i`m a little bit stuck.

I have to check if post title has certain word in it and then give it a certain category. One post can have multiple categories.

How do i do it?

Switch without breaks so it checks every possible word?

    switch ($title) {
        case ($pos = strpos($title, 'xxx')):
            $this->updatePostCategory($id, Admin_model::XXX);
        case ($pos = strpos($title, 'asd')):
            $this->updatePostCategory($id, Admin_model::ASD);
    }

Many if statements under each other?

    if (strpos($title, 'xxx')) {
        $this->updatePostCategory($id, Admin_model::XXX);
    }
    if (strpos($title, 'asd')) {
        $this->updatePostCategory($id, Admin_model::ASD);
    }

What would be best practice here?

Thanks :>