[souprock]

Quality packaging reduces spoilage, and thus reduces waste. A stack of slices wrapped up by a deli will spoil long before individually sealed slices.

Longer shelf life enables efficient shipping and shopping, which reduces trips taken. This counts towards fuel use, road wear, and vehicle wear.

Counting both the waste and the product that gets used, the total cost is a rough approximation of environmental impact. The less you spend, the lower your impact.