Obviously fresh foods spoil fastest (think produce, fish, meats and dairy) so they are replenished more quickly and the thin supply chain (field to fork) passes along increased costs fast. Processed foods have a longer shelf life (boxed, canned, frozen, etc), and as a consequence have a much larger inventory level in manufacturing, warehousing and retail storerooms/shelves. Within processed foods, there is a lag between cost increase at origination and that cost hitting the stores.