Update List

<?php

function updateList(array $list) {
  foreach($list['currentList'] as $currentEntry => $currentVal) {
    foreach($list['newList'] as $newEntry => $newVal) {
      // we have a hit
      if ($currentEntry == $newEntry) {
        $list['newList'][$newEntry] += $list['currentList'][$currentEntry];
        continue 2;
      }
      // last entry hit
      if ($newEntry == end(array_keys($list['newList']))) {
        array_push($list['newList'][$currentEntry], $currentEntry);
        $list['newList'][$currentEntry] = $currentVal;
      }
    }
  }
  return $list['newList'];
}

// Testing
$InventoryList = array(
  'currentList' => array(
    'Chicken' => 2,
    'Pork' => 3,
    'Ginisa Mix' => 1,
    'Tissue Roll' => 3,
    'Beef' => 5 ),

  'newList' => array(
    'Chicken' => 3,
    'Beef' => 2,
    'Beer' => 3,)
);

print_r(updateList($InventoryList));