Ham slice do not spawn naturally and can only be obtained through crafting.
Shortly after the addition of ham slice in build 34, the community claimed the icon had some resemblance to a penis and was changed to its current icon. After public outcry, the icon now has an annual tradition on The Indie Stone forums for an event known as Week of the Penisham, where the penisham icon can be used as a reaction emote. The icon is also available in the official The Indie Stone Discord server]. Finally, in Build 42, a new vehicle with the advertisement for Penn S. Ham Construction was teased, having bricks stacked similarly.
Ham slice model when placed in the world.
Original ham slice icon, now known as penisham.
From items_food.txt (Project Zomboid directory/media/scripts/)