I have heard saw dust as well. I myself think it would be too messy in the foodpack. However our group has gotten better at how we keep thing cool. We used to just layer it in tin foil. However this year we layered it in both newspaper, and the tin foil. For the long drive up we keep it in a cooler with a lot of ice. The meat was still frozen when we unwarped it3 days since it was last in a freezer.

I belive sawdust was originaly used back in the days when people used ice boxes to keep food cold. The only way they could keep the ice from melting in summer was to put it under sawdust.

L.T. wrote: I myself think it would be too messy in the foodpack.

Most of the food was inplastic bags so a quick rinse and it was ready to go.

SD was used in Ice Houses and that's where I got the idea.

Many of the cabins on Lake Vermilion, where I live, did not have electric power available until around 1950.  Most had their own ice houses; which now are turned into storage sheds.
I helped put up ice when I was young.  Ours would last into August and we used it in old fashioned ice boxes.  We would dig a block out of the sawdust, take it to the lake and dunk it to clean it off, then to cabin and into ice box.
I think the sawdust idea for packing food sounds like a good one.
Now I freeze water in several 1 liter pop bottles and use them for the ice packs in my cooler.  As they melt you can enjoy the fresh and COLD water for 2-3 days on the trip.  Then I use them to store filtered water at camp and on the trail.  One of our party is put to work filling them with filtered water in the morning, and then it is handy all day while traveling.

This year I experimented with a soft-sided cooler as part of the food pack.  We packed it completely full with our steaks (the one thing that we really wanted the cooler for) and stuffed the rest of it with our salami, bacon, and jerky.  Those other items didn't really need to be frozen at all, but we used them in place of ice.

All the stuff went into the freezer at home pre-trip packed in the soft-sided cooler with the steaks surrounded on all sides by the other items.  We pulled the cooler out of the freezer and zipped it up to put in the food pack the night before we left.  Once we got to the outfitters, we asked to store the cooler (with the top open) in their freezer.  The next morning, we got our cooler out, zipped it up, and placed it in the food pack.  The plan was to have steak that night.

I figured the steaks might still be soft-frozen when we hit camp and need an hour or so out on a rock to finish thawing.  We hit camp about 4:00, I checked the steaks and they were still frozen hard as a rock!  Only the stuff on the outer edges of the cooler was starting to thaw at all and even that was still pretty hard-frozen.  I quickly zipped shut the cooler and we had a quick conference.  We decided we still had time to catch dinner out of the lake and that the steaks would likely still be good for dinner on day #2.

Day #1 had been sunny and in the 70's and we'd taken no real precautions to keep the food pack out of the sun.  Day #2 was more like 80 degrees with strong sun.  Once again, no attempt was made to keep the food pack out of the sun all day.  We hit our next campsite late afternoon and I zipped open the cooler hoping the steaks would have survived.  Sure enough, the steaks were still soft-frozen, but at least we had time to thaw them before dinner.

That evening as we enjoyed our steak dinner deep in the Q, we theroized that we could have easily brought ice cream in for the 1st or 2nd night if it was buried in the middle of our cooler.  Now that would be a treat! 

Upon exiting, we stopped by a grocery store on the way back and saw they had freezer bag liners for coolers which were basically a foil bag to reflect heat out and cold in.  They might have allowed us to keep foods frozen even longer.  I intend to find out next year!  I'm not going so far as packing in gallons of milk and Frosted Flakes like some folks apparently do  but a little ice cream might be worth the effort.  Worst case scenario, we'd drink it like a shake.

I think this system probably works plenty well without the need to pack in ice or sawdust.

We took REAL ice cream once. There was Hershey's syrup in the bag too. It was a chocolate shake by day three in July. Cold & good but straws would have been a better idea.

I was thinking steak and only steak packed in sawdust inside foam - that's it. Just steak. The rest of the stuff really has no need to be in a cooler although I do agree with IC in that 32˚ water is pretty special too after a few days.

Last year before my first August trip in a long time if ever, I was thinking "dog days" and did some dumpster diving for 1" pink foam insulation. I made a box out of it using bathroom caulk as glue that fit inside my cheap soft sided cooler. Only problem was, at Int. Falls they took everything out and spread it all out on one of their big heavy stainless steel tables... Arrrrrgh! I had steak on day two or three - I forget. I just remember it was way earlier than I planned on. Not a big deal, just aggravating after the effort and construction. I still have it. Might try covering it in foil next time.

I've always put thermometers in my coolers. It's not unusual to have solid ice and solid steak while the other food is above 50˚ even in Spring if you don't treat the cooler well. Just because something is frozen solid doesn't mean the other food as cool as you'd like.