pre_get_posts question

Hi I want to filter query only for one category.

My original filter was :

add_action('pre_get_posts', 'remove_old_apple');
function remove_old_apple(&$query)
{
  	if (is_category()&& empty( $query->query_vars['suppress_filters'] ) ) {
        $today = date("m.d.y");
        global $custom_remove_old_apple;
       	$query->set('meta_key', 'date_maj');
        $query->set('meta_value', $today);
        $query->set('meta_compare', '=');
        }
}

And work for all category page, but I want to filter only on the category ID 39 so I try this

add_action('pre_get_posts', 'remove_old_apple');
function remove_old_apple(&$query)
{
 	if (is_category('39')&& empty( $query->query_vars['suppress_filters'] ) ) {

        $today = date("m.d.y");
        global $custom_remove_old_apple;
       	$query->set('meta_key', 'date_maj');
        $query->set('meta_value', $today);
        $query->set('meta_compare', '=');
        }
}

Why out any success. Do you have some suggestions?
Thanks for your help