ElementAPI : Excluding terms from search criteria
Here is what I ended up changing my code to exclude search items. 

//Get excluded ingredients query
$excludedQuery = Craft::$app-&gt;request-&gt;getQueryParam('xq');
if ($excludedQuery) {
    if (!isset($criteria['search'])) {
        $criteria['search'] = '';
    } else {
        $criteria['search'] = $criteria['search'].' ';
    }
    $criteria['search'] = $criteria['search']."-title:'".$excludedQuery ."' -recipeIngredients:'".$excludedQuery ."' ";
}