The diaries refer to dried meats and canned meats, and the labaz had 8 day's worth (the tent 3) of cooked sausages, canned meats and what the labaz finders called brisket.
https://dyatlovpass.com/maslennikov-notebook-2The dried meat would likely be air-dried, and a diary entry reveals this is what they ate on the go. Unknown Diary, Jan 30th
"At approximately 2 pm we stop for a lunch. Dried meat, guest crackers, sugar, garlic, coffee, stocked in the morning - that's our lunch."If they had any raw meats I suspect these would be consumed when the weather permitted a fire, and if they were too tired or it was too windy they'd revert to their ready-meals, as it were.
I always thought it odd they didn't have a rifle on this hike, not just for defence when out in the wilderness, but also to hunt with should they be holed up through bad weather and their provisions ran out. Previous hikes tend to show 1 if not 2 rifles.
Presumably on this one the idea was to take lots of prepared meats, which in turn added weight (including 3kgs of salt which may have been to help preserve things) and this weight may have seen them dispense with some useful things, such as the radio Igor normally took with him (which, I don't know, may have provided weather forecasts to inform them of an incoming storm, assuming they could get reception when at altitude).
It's interesting to consider the possibility of food poisoning or other poisoning on this hike, because the DPI isn't really just about the mystery of their final night, it's also the number of odd things which led up to it, and if they were not functioning normally, so they didn't have their wits about them, then their survival odds when faced with a storm might be poor despite their apparent 'experience'.
For example top-of-the-class Zina repeatedly didn't know what month or even year it was in her diary, and also misunderstood how a camera aperture works in part of her notes. Aleksander, unless lying, told them it was his birthday on 30th, the day after Yuri D's, when it was 16th November. Lyuda behaved as if clinically depressed from Vizhay onwards, and looked very pale on the hike, and she spent that 'birthday' party inside the tent. There seemed to be some bickering going on, recorded in diary entries, people not attending to their duties, including wake up calls.
Nobody except Igor made a diary entry the day before they died, and although detailed, his final sentence suggested they'd be "hundreds of kilometres away from human settlements" if up on the Ural ridge, when they were at best 50kms from Vizhay. They also misnavigated by going up the wrong pass. And what sort of decision making has a group of experienced hikers ascending a mountain at 3pm, a couple of hours off nightfall, as a storm approaches.
As the hike progressed, from day 2 or 3 onwards, they seemed to struggle more and more, their progress slowed to a crawl, they had to jettison weight, and yet another group in broadly the same conditions managed to complete their trek.
One possible explanation for this would be E.coli. It can affect mental functioning, cognition and memory, left untreated it can cause brain damage. And seizures are common, potentially explaining fluid around the mouth, and superficial injuries to hands and heads. It can make people bad tempered, pale, and have aches in their flanks/back, which would increase the burden of carrying weight. It can also affect the urinary system and cause fluid retention, so thinking here of how Igor's bladder was fit-to-burst at autopsy, with a litre of urine.
It doesn't usually cause vomiting, more the runs. If looking for potential evidence of that, there was mention in the diaries of Tibo changing his clothing, and it's hard to see why that would otherwise be a noteworthy thing to record. The 'yeti' photo shows a man, possibly Yuri K, who does not have his trousers on. Semyon's autopsy revealed he had soiled himself, and though we don't know exactly what she meant, Nurse Solter said the hikers were "very dirty".
E.coli typically has an incubation period of around 3 to 4 days. Had their own foodstuffs been contaminated then unless they'd already consumed the bad stuff the rescue team should also have been affected because they consumed the food found in the labaz. So this makes me wonder about that evening meal they had at Vizhay, which Blinov's group avoided as they didn't stay the night. Goulash and cold tea. E.coli can be in water, and goulash is the sort of stew any old meat can be hidden in, and possibly reheated.