WordPress Search Results – Check for custom post type

I am using the custom post types in my wordpress blog and want to have a different icon for each type of post.

<?php if ( is_post_type( 'team' ) ) {
    echo '<img src="team.png" />';}
else
{
    echo '<img src="page.png" />';
}?>

But I get following error message: Fatal error: Call to undefined function is_post_type().

Any suggestions?