At first it seemed like some old testament blessing. Forests began rapidly reclaiming land, crops seemed to grow as fast as they could be planted, and every birth was twins. Any joy at what seemed good fortune was restrained by paranoia at the strangeness of events, a paranoia that would prove justified. The inexplicable fertility boost applied to life of all types and every scale, and soon crops were being devoured by pests as soon as they could be planted, fruit rotted on the vine, and every birth revealed a new type of birth defect. The year of plenty was the precursor to the "the terrible winter", when food stores proved inadequate, the triple flu burned the world, and half of humanity died.
Then changes began to appear in larger forms of life. Animals with birth defects began to survive, even interbreed, becoming new species. There are, for example, the blind dogs, eyeless but with incredible hearing and smell, which have largely supplanted coyotes and wild dogs. Earth's ecosystems now include carrion monkeys, horse-melds, gossamer spiderlings, and many, many others. Some breed true, others appear to be unique. Humans are not immune to these changes.
Food now is a source of continual paranoia. Crops are often lost to diseases or pests. When harvested, foods are immediately placed in sealed containers. They are not removed until necessary for processing, at which point they will be examined for infections, sterilized (typically by UV light), and repackaged for sale, typically in clear plastic containers. The only truly trusted food sources are the sterile vertical farms of the white zones, and even then, the most popular cooking technique is thorough boiling.