Stale suggests the idea of food which is no longer fresh but still edible:

no longer new or fresh, usually as a result of being kept for too long:

• The bread/biscuits/cake had gone stale.

(Cambridge Dictionary)

If it is still edible but not in the state that its makers would have preferred it is "past its best".

Although the word "stale" conveys the same meaning with some foods, such as bread/biscuits/cake, it does not do so with all foods, such as, say, cheese.

I think it all depends on the foodstuff in question. If it is fruit then "over-ripe" might do

passed beyond maturity or ripeness toward decay (Merriam-Webster).

And yet, my Aunt was fond of medlars. That is a fruit that is eaten only after it passed beyond maturity towards decay.

And what about well-hung pheasant or grouse?

That all leads me to the view that no single word will encompass all the ideas that the OP has in mind.

off

See meanings 2 and 4:

Adjective: off (óf)

1. 
   

   Not in operation or operational

   
   
   

   "the oven is off"; "the lights are off"

   
   


2. 
   

   Below a satisfactory level

   
   
   

   "an off year for tennis"; "his performance was off"

   
   


3. 
   

   (of events) no longer planned or scheduled

   
   
   

   "the wedding is definitely off";

   
   
   
   • cancelled [Brit, Cdn], canceled [US]
   
   


4. 
   

   In an unpalatable state

   
   
   

   "off milk";

   
   
   
   • sour, turned
   
   



5. Not performing or scheduled for duties
   "He's off every Tuesday"

-- WordWeb

As can be seen for #4, unpalatable is another term for what you describe:

Adjective: unpalatable (ún'pa-lu-tu-bul)

1. 
   

   Not pleasant or acceptable to the taste or mind

   
   
   

   "an unpalatable meal"; "unpalatable truths"; "unpalatable behaviour"

   
   
   

   See also: brackish, distasteful, inedible, offensive, tasteless, unappetising [Brit], unappetizing, uneatable, unpleasant, unsavory [US], unsavoury [Brit, Cdn]

   
   

Antonym: palatable

The best all-purpose word is really edible, like @Vaelus noted on @Rob's answer. You don't use it to describe desirable food, just stuff that's barely passable. Speaking of which,

passable

is one possible word that hasn't been mentioned yet.

2. Of adequate or acceptable quality; sufficient; satisfactory. In later use: just good enough to be acceptable.

1893 June 12, The Times, p. 4:

Potatoes appear in eight departments... very good, 13 good, 17 satisfactory, 18 passable, six mediocre, and three bad. [sic]

Another word might be suitable : substandard.

: deviating from or falling short of a standard or norm: such as
a : of a quality lower than that prescribed by law
substandard housing

Merriam Webster

1. Of less than the required or normal quality or size; of a lower standard than required, inferior.

Oxford English Dictionary

The most common phrase for this -- I remember from my Mum as a child -- was that the food was:

On its last legs

cambridge Something that is on its last legs is in such bad condition that it will soon be unable to work as it should

The key thing is described exactly the correct state of the food. It is nearly inedible, but it is still edible.

Unlike other phrases that just mention the food being substandard - and give no indication that it's become substandard over time - the focus here is the degradation; it is OK right now - but if it's left any longer it won't be.

I say the item has passed its prime.
Or the item is past its prime.

Meaning it is not in optimal condition but hasn’t reached a spoiled state yet.

A hypernym of freezer-burned ice cream and re-crystallized sugars is old. It may be past its expiration date, "but it's still good."

Sorry, this is not a single word, but I think it fits better than the other proposals so far:

not at its best

This fits the two examples you gave, of the crystallized honey and the ice cream with ice crystals. It would also work for green beans that need a lot of trimming, slightly rubbery broccoli, slightly wilted lettuce, breaded chicken cutlets that were heated up three times and have gotten rather dried out and chewy.

Some alternatives with a similar flavor:

seen better days

a little worse for wear

not the pick of the crop

Some examples:

These green beans have seen better days.

This ice cream is not at its best.

This lettuce is looking a little worse for wear.

These peaches are not the pick of the crop.

There is no suggestion that any of these foods will do you any harm -- they're just suboptimal.

Well, I guess there you have a single word:

suboptimal

But it's not as colorful.

Food spoilage refers to the action of bacteria or fungi (mold, yeast) that make the food go “bad”, ultimately dangerous to eat.

Food grading, on the other hand, is a question of quality and freshness. Food that is not fresh may suffer in flavor and texture, although it may be safe to eat. Nutrients may also be lost.

There are many processes (evaporation, melting, or oxidation) that may degrade foods; some changes can be reversed (e.g., crystallization), and the degraded part may be removed. You can get rid of crystals on ice cream, but the part that’s been melted will be degraded, although not necessarily spoiled.

So degraded (more specific than old) is a good term for this, although not what people would use in conversation.

Word for Food that's Gone 'Bad', but is Still Edible?

Which side of the line a definition sits can be the subject of some debate, it is cultural in north American English to separate the terms "good" and "bad" when referring to food, there is no overlap or middle ground.

Both culture and prosperity can play a role in definitions of something so important, it's both important to eat but in north American it's important that the quality be of a particular level, IE: not "bad", by a long stretch.

unwholesome adjective

: detrimental to physical, mental, or moral well-being : unhealthy, unwholesome food

• "Health inspectors shut down several food stands that were using tainted and unwholesome meat."


• "A diet of fried foods and pizza is unwholesome."

You can bend the definition of one word either way, but there's no overlap, it doesn't mean the same thing. The ability to stretch one word to cover both extremes doesn't equate the meaning.

If food has gone bad it's not edible:

edible adjective

: fit to be eaten : eatable

edible noun

: something that is suitable or safe to eat : something edible

Food that is "bad" is by definition "no good" to eat, unless you wish to eat bad food.

Proverb: "Food you will not eat you do not boil.".

A lot also depends on culture and definition. One Roman proverb is "More die by food than famine.", another is: "Jejunus raro stomachus vulgaria temnit: a hungry stomach rarely despises common fare (also translated: the stomach that is rarely hungry despises common fare) (Horace)".

A couple of Filipino proverbs are: "There is no bad food in a famine." and "There is no bitter crust to a hungry person." A Catalonia proverb is: "In times of famine no bread is stale.". None of those proverbs make the food more or less edible, it is the state of hunger, the need, that makes one more tolerant of a lower standard.

Take for example hákarl (a national dish of Iceland) and hongeo-hoe (Korean); which are cartilaginous fish that excrete uric acid through the skin, rather than by urinating as other animals do. These fish are simply buried and left to ferment, utilizing the ammonia as a preservative.

In the case of hákarl the meat of the Greenland shark is poisonous when fresh, due to a high content of urea and trimethylamine oxide, but may be consumed after being processed.

In the case of surströmming, (Swedish for "sour herring"), just enough salt is used to prevent the raw herring from rotting. A fermentation process of at least six months gives the fish a characteristic strong smell and somewhat acidic taste. According to a Japanese study, a newly opened can of surströmming has one of the most putrid food smells in the world, stronger than similarly fermented fish dishes such as the Korean hongeo-hoe or Japanese kusaya.

Ambergris is formed from a secretion of the bile duct in the intestines of the sperm whale. Once expelled by it often floats for years before making landfall. After months to years of photodegradation and oxidation in the ocean the excrement gradually hardens, developing a dark grey or black colour, a crusty and waxy texture. It has a peculiar odour that is at once sweet, earthy, marine, and animalic.

Those are foods which by some definitions sit on the line, but they are not "bad" per se, they are edible; despite being stored in urine or composed of feces and left to rot.

The closest north America gets to food that appears bad is with cheese or sausage which might be covered in mold, but this is not rotten, it's a harmless bacteria that prevents the formation of more dangerous bacteria. Since it either passes food inspection or it does not it is either good or bad; not both.

The examples you offered, "honey that has crystalized" and "ice cream that has ice all over it" can be eaten as-is. There is nothing that you are required to do to it. Crystallized honey simply has a different texture and icy ice cream is simply ice cream with ice.

Joke: The exception is given by the "5 second rule". Such food is "bad" to eat, but not spoiled or moldy (unless you drop it on mold). There often is no difference in the appearance and even testing might show one such dropped sample is no worse than a sample that was not dropped.

The two concepts "gone bad" and edible are in opposition to each other, like long and short. Even a freeganist makes an effort to avoid "bad food", despite eating out of a dumpster. If it's good to eat it's not bad, if it's bad it's no good to eat.

I'm astonished no one has mentioned sketchy.

Sketchy: Merriam Webster online dictionary, https://www.merriam-webster.com/dictionary/sketchy

: QUESTIONABLE, IFFY

got into a sketchy situation

a sketchy character

and in the MW learners dictionary at the same link -

US, informal : likely to be bad or dangerous

as in this delightful headline -

Dining Hall Foods Ranked From Most to Least Sketchy

https://spoonuniversity.com/lifestyle/dining-hall-foods-ranked-least-sketchy

Since this is apparently only common in the US, a bit more about the usage seems warranted. Sketchy isn't used much for whole foods or raw foods, it is used to refer to cooked or otherwise prepared foods that are understood to have a shortish life after preparation. This could be due to legitimate heath concerns, or just cosmetic issues. Fresh guacamole gets sketchy rather quickly, turning brown on the surface. Tuna salad gets sketchy because food poisoning is a real threat.

It’s not uncommon for any one of us to have a hospital visit for food poisoning, but eating some sketchy guacamole doesn’t come with a 6.7% chance of killing you while medical teams are scrambling to hook you up to a respirator.

https://insh.world/culture/dangerous-foods-around-world/

I love tuna salad and eat it once a week. Canned Tunafish can be either an awesome healthy choice or flat-out sketchy depending on which kind of canned tuna you buy. Sketchy for your health and sketchy for the environment. So you have to be a label reader!

https://www.healthyseasonalrecipes.com/mediterranean-tuna-salad/

Whilst passed its prime and past its best have both been mentioned, no one has suggested past its sell-by-date, for example:

This mooli/pig's trotter/camembert is past its sell-by-date but I think we can still eat it...

This might be a bit colloquial, but in British-English at least, it is commonly used.

The word you are looking for is edible.

Yes, of course, edible technically also covers food that is in prime condition but there are almost no circumstances under which you would describe such food as "edible". Describing something as edible is damning it with faint praise, implying that it can be eaten is about the best that could be said about it.

My only reservation with recommending "edible" is that it can also be applied to food that is badly cooked or prepared such that the best can be said about it is that it is "edible", however I think this should be clear from context. Otherwise I don't think there is a single, generally applicable word; since although words such as stale, soggy, or soured could be used to refer to the problem when referring to specific foods (or drinks) they are not appropriate for all examples.

I suggest the idiom "on the turn".

I heard this phrase used by a person from the north of England (a "northerner") on a comedy panel quiz on BBC TV.

Written definition from Collins Dictionary:

about to go rancid