Which of these Ingredients/additives assist in the longevity of frozen, microwavable foods?

My last question was closed due to egregious subjectivity so I'll be very objective with this post.

Premise: Frozen, microwavable foods are "usually fully cooked during preparation, and only need to be reheated". Microwavable dinners are "formulated to remain edible after long periods of storage".

If I cook some fettuccine Alfredo, mix the pasta together, store it in the refrigerator, and microwave it the next day (or next week), the sauce will objectively separate, and (I guess this is subjective but who would argue) the left overs have a taste and feel which are degraded compared to that which came right off the stove.

If frozen foods are formulated to remain edible after long periods of storage, then the ingredients used to formulate such foods are responsible for this longevity. Therefor, which of the following ingredients in Stouffer's Fettuccine Alfredo are responsible?

I am particularly interested in ingredients that I as a consumer can have control over to experiment with. For example, from my other question I learned that the food technologists at these companies have altered their starch (called "modified starch"), which I am unable to do.

Here are the main ingredients as far as I can tell:

blanched fettuccine (water, semolina, wheat gluten)
cream
skim milk
soybean oil
Parmesan cheese (cultured milk, salt,enzymes)
2% or less of water
asiago cheese (cultured milk, salt , enzymes)
modified cornstarch, Romano cheese (pasteurized milk, cheese culture, salt, enzymes)
salt
enzyme modified Parmesan cheese (cultured milk, water, salt, enzymes)
whey protein concentrate

Here are the non-main ingredients as far as I can tell:

lactose
datem
xanthan gum
lactic acid
calcium lactate
seasoning (maltodextrin, flavor, enzyme modified butterfat)
seasoning (wheat starch, extracts of annatola and tumeric color, natural flavor)

From my question that got closed, I learned that xanthan gum was very useful as an emulsifier and making the sauce thicker. Emusifiers should prevent the sauce from coming apart in the microwave.

Datem = derived from tartaric acid, lowers pH, and is an emulsifier

Lactose "may be used to sweeten stout beer; the resulting beer is usually called a milk stout or a cream stout."

Lactic acid "Lactic acid is used as a food preservative, curing agent, and flavoring agent. It is an ingredient in processed foods..." It is also used to lower pH in beer.

Calcium lactate, I couldn't find too much on. From this interesting site it appears to be used in a lot of cheese products.

Maltodextrin " improves the mouthfeel of the beer, increases head retention and reduces the dryness of the drink. Maltodextrin has no flavor and is not fermented by the yeast, so it does not increase the alcohol content of the brew. It is also used in snacks such as Sun Chips. It is used in "light" peanut butter to reduce the fat content but keep the texture"

Annatto appears to be a food coloring