Packages covered with a sealed layer of clear plastic are modified-atmosphere packages, which have a gas-filled space inside to help preserve freshness and color.

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Which makes sense, given the ingredients used to preserve and give them their color are derived from petrochemicals and butane.

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One night in early autumn, with the swampy ground of the Nature Preserve papered with fallen leaves, I was hunkered down to examine a dead snake about a foot in length whose color I thought might in life have been green, when, as I stood, I felt something brush the top of my head.

NEWYORKER: Wakefield