Removing an item from object in a loop

I have a set of Db results that are stored in an object. I need to loop through the results and check a property (using another DB query) and then use an if statement to remove the item from the object. Here is a simplified version of what I'm attempting:

foreach ($products as $product) {

    if(!$product->active) {
        unset($product);
    }

}
print_r($products);

However when I print_r the items are still in the object. I'm getting confused.