I would appreciate it if you could tell me what the problem is with the PHP query

<?php

require_once 'connBarcode.php';

if(isset($_GET['barcode'])) {
 $key = $_GET['barcode'];
 $query = "SELECT * FROM food WHERE barcode='$barcode'";
 $result = mysqli_query($conn, $query);
 $response = array();
 while($row = mysqli_fetch_assoc($result)) {
      array_push($response,
      array(
         'barcode'=>$row['barcode'],
         'food_name'=>$row['food_name'],
         'company_name'=>$row['company_name'])
      );
   }
echo json_encode($response);
}

mysqli_close($conn);

?>