如何防止codeigniter中的数据重复

I have problem on displaying data of $variant_choice, which it will be called repeat as long as i select a data from same id.

This is my code how to call $variant_choice:

if(($a["choice"])!== NULL) {
   foreach($a["choice"] as $val){
       $variant_menu_choice[] = $this->Restaurants_m->m_get_menu_choice2_by_id($val);
   }

}
foreach($variant_menu_choice as $value){
    $choice[] = $value["variant_name"];
}

$variant_choice = implode("<br/>",$choice);

Example :

If i click a data golden_salmon which it will contain $variant_choice. First if i choose spicy in golden salmon, it will nothing problem, but if for the secondly i choose another $variant_choice as salty, it will be return become spicy and salty