Get Array of category IDs

Hi,
I would like to get an array of all the category IDs for each store so that I can check them against a ‘preferred category’ saved in a users profile.
I am unable to get an array of the term_ids – I am using this function to succesfully display the IDs in the store template.

function custom_store_meta1( $store_meta, $store_id ) {

	$terms = get_the_terms( $store_id, 'wpsl_store_category' );

	$store_meta['terms'] = '';

	if ( $terms ) {
		if ( ! is_wp_error( $terms ) ) {
			if ( count( $terms ) > 1 ) {
				$location_terms = array();

				foreach ( $terms as $term ) {
					$location_terms[] = $term-><strong>term_id</strong>;
				}

				$store_meta['terms'] = implode( ',', $location_terms );
			} else {
				$store_meta['terms'] = $terms[0]-><strong>term_id</strong>;
			}
		}
	}

	return $store_meta;
}

In the custom template I am making an array of the term IDs like this:

    $terms_array = '<%= terms %>';
    $terms_array = explode(',', $terms_array);
    print_r($terms_array);

The result is Array ( [0] => 31,22,25 ) which is not a proper array…

In summary – how could I get an array of the store’s terms/categories from within the custom store template?

Thanks