Better array_key_exists() function??

public function getCombinedIngredients()
    {
        $ingredient_list = array();
        foreach ($this->recipes as $recipe) {
            foreach ($recipe->getIngredients() as $ing) {
                $item = $ing['item'];
                if (strpos($item, ",")) {
                    $item = strstr($item, ",", true);
                }
                if (in_array($item . "s", $ingredient_list)) {
                    $item .= "s";
                } else if (in_array(substr($item, 0 , -1), $ingredient_list)) {
                    $item = substr($item, 0 , -1);
                }
                $ingredient_list[$item] = array($ing["amount"],$ing["measure"]);
            }
        }
        return $ingredient_list;
    }

echo Render::listShopping($breakfast->getCombinedIngredients());

echo Render::listShopping($cookbook->getCombinedIngredients());