array_items_count.php

<?php
class ArraySearch 
{
    public static $occurences = 0;

    public static function countItems($arr, $item) 
    {
        foreach ($arr as $key => $value) {
            if (is_array($value)) {
                ArraySearch::countItems($value, $item);
            } else {
                if ($value === $item) {
                    ArraySearch::$occurences++;
                    continue;
                }
            }
        }

        return ArraySearch::$occurences;
    }

}

$arr = [
    "apple",
    ["banana", "strawberry", "apple"],
    ["burrberry", "grapes"],
    ["apple", "cherry", ["melon", "apple"]],
    ["apple", "cherry", ["melon", ["apple"]]],
    "tomato"
];

echo ArraySearch::countItems($arr, "apple");