Frozen foods do not require any added
preservatives to keep them safe and consumable, because microbes
cannot grow on food that is at a temperature less than 0°F. The
microbes do not die at that temperature, but they stop multiplying
and can come back as food is unfrozen.
Despite some old wives’ tales, freezing food does not remove any
nutrients.
Freezer burn is just the result of air hitting frozen food and
allowing the ice to sublimate; other color changes can be blamed on
long freezing times or poor packaging. It might look gross, but if
your frozen food has maintained a proper temperature, it is fine to
eat.
Freezing food typically keeps items edible indefinitely, although
taste and quality may diminish over time. Some items that stay tasty
even after long freezes include uncooked game, poultry, and meat,
which are still good after up to a year in the freezer.
Even though freezing food was used as a storage technique in cold
weather climates for many years, it is believed it was first applied
to industrial food sales sometime in the 1800s, when a Russian
company froze a small quantity of duck and geese and shipped them to
London. By 1899, the Baerselman Bros. company adapted frozen storage
for their own Russia-to-England food shipping business, though they
initially only operated during cold weather months. Birdseye fact
here LINK.