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How Safe Is Your Food? Investigating the effectiveness of odor-proof bags
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Ryan Jordan
(ryan) - BPL Staff - MLife

Locale: Greater Yellowstone
How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 00:09:28 MDT Print View

Companion forum thread to:

How Safe Is Your Food? Investigating the effectiveness of odor-proof bags

Johan Engberg
(luffarjohan) - M

Locale: Wrong place at the right rime
Bandana on 04/10/2013 00:48:00 MDT Print View

Interestning but not surprising. After having seen trained dogs look for human tracks on pavement, humans in avalanches, munitions, truffle or whatever, it's easy to believe there's no limit.

One important thing to think about when avoiding "scent detection" is wind direction. May be hard to predict bear direction though...

I only have brief experience with hiding food in bags in the smokies one night a couple of years ago. Since where I usually roam there's no need for food-bags it was all new to me. Turned out ok but my measures where literally worthless if a bear would have been close.

But to the question! What's the brand and the weight of the see-through bandana the officer in the 4th picture has over his eyes?
I see multi-purpose use, sunglasses and cap. :)

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 00:58:44 MDT Print View

Well done. I'm glad this experiment was completed, and from a layman, it is a little surprising. Thanks.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 01:06:15 MDT Print View

Way to go!

Demonstrating marketing 1, science 0, for the claims.
Most excellent study.

Cheers

Philip Marshall
(philthy) - MLife
Can never ignore an article with dogs in it... on 04/10/2013 01:09:32 MDT Print View

Wow, this is really great, well done organising this.

I find the results unsurprising and a good reminder that there aren't any shortcuts to bear safety.

Travis Leanna
(T.L.) - MLife

Locale: Wisconsin
the animal kingdom on 04/10/2013 01:13:12 MDT Print View

The Animal Kingdom never ceases to amaze. I'd MUCH rather hear about this kind of thing in the news than the nonstop stupidity of our fellow humans.

Bradley Danyluk
(dasbin) - MLife
Quantum noses on 04/10/2013 02:05:02 MDT Print View

Amazing stuff. Many thanks for such a thoughtful and meticulous study.

J P
(jpovs) - F - M

Locale: North Shore
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 05:29:34 MDT Print View

-

Edited by jpovs on 06/27/2014 22:21:26 MDT.

Tony Ronco
(tr-browsing) - MLife
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 06:15:30 MDT Print View

Excellent Study - Much Thanks for publishing it.

Raises a lot of interesting questions in my mind ... here are two:

I wonder about the rates of permeability ... given how quickly the dogs found their targets it doesn't seem like doubling the bags would help.

I also wonder about vacuum sealer bags used for home dehydrated meals. (If odiferous smells can get permeate out, then can O2 permeate & get in? ... same question about commercial freeze-dried offerings)

Ok, Art - when are you going to publish the next set of experiments? :-)

Mike V
(deadbox) - F - M

Locale: Midwest
RE: "How Safe Is Your Food? Investigating the effectiveness of odor-proof bags" on 04/10/2013 06:34:54 MDT Print View

excellent article! I am not surprised by the findings, although I still believe OP sacks likely reduce odor transmission better than a standard zip lock and still have some value when used in conjunction with a proper hang or inside of a bear canister.

Ben Crocker
(alexdrewreed) - M

Locale: Kentucky
How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 06:50:51 MDT Print View

Great work. I have always been sceptical of the OP bags and have not purchased them. I assumed they were no better than ziplocks. But I am a little surprised though that neither seems to have much useful effect.

Ike Jutkowitz
(Ike) - M

Locale: Central Michigan
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 08:08:41 MDT Print View

Thanks for the nice comments, guys. We had fun performing this study and the dogs thought it was a great game.


"I am a little surprised though that neither seems to have much useful effect."
@Ben- We only looked at whether the odor-proof bags performed better than ziplocs. We did not address the question of whether either had a useful effect at all. Here is an abstract suggesting that ziplocs may decrease bears ability to smell food, though one has to wonder whether the difference between 6 and 9 seconds is significant in a practical sense.

Wilderness & Environmental Medicine
Volume 21, Issue 4 , Pages 375-376, December 2010

Ziploc Bags for Preventing Bears from Smelling Food

Background.—Wilderness activities occasionally result in
bear-encounters. To deter bears from detecting food scents, the
American Bear Association recommends double-bagging food
carried into the wilderness.
Objective.—Our objective was to determine if food sealed
in double-bagged Ziploc bags would decrease the ability of
bears to detect food scents as compared to food in unsealed
Ziploc bags.
Methods.—This was a prospective randomized singleblinded
study performed on bears at Northwest Trek Wildlife
Park, WA. Two black bears (Ursus americanus) and 2 brown
bears (Ursus arctos) were presented with open buckets in front
of their enclosures: one concealing food wrapped in 2 layers of
Ziploc bags and another with empty Ziploc bags. The time the
bears spent at each bucket was recorded for 30 seconds. In the
first phase, Ziplocs were open; in the second, Ziplocs were
sealed.
Results.—The average time the bears spent at the open
Ziplocs with food and open Ziplocs without during the first
phase of the experiment was 9.573 and 6.613 seconds, respectively
(N _ 75). The average time spent at the closed Ziplocs
with food and closed Ziplocs without in the second phase of the
experiment was 6.25 and 6.8875 seconds, respectively (N _
80). The standard deviation for all average times was 1.5
seconds. An independent samples 2-tailed t-Test demonstrated
a statistically significant difference (P _ 0.032) when compar-ing
the time the bears spent at the open Ziplocs with food to the
closed Ziplocs with food. There was no statistically significant
difference between the controls from both phases of the experiment
(P _ 0.854).
Conclusions.—The bears spent a statistically significant
greater time at the open Ziplocs with food compared to the
closed Ziplocs with food. These data suggest that sealing food
in 2 layers of Ziploc bag may decrease the ability of bears to
detect the scent of food from within. We advise following the
ABA recommendations.

Clark M. Rosenberry, MD
David C. Hile, MD
Troy H. Patience, BS
Fort Lewis, WA, USA

Richard L. Sartor, MS
Angela K. Gibson, MS
Northwest Trek Wildlife Park, WA, USA

@Tony- I can answer your question about foodsaver bags, though not with a direct comparison. I had relied on the police officers to provide the "scent packets" for the study. Naively, I only questioned type and weight of the product, but not how they were packaged. After the study, I theorized that the seal must be the weak link in these bags and proposed a second study where we would investigate bags that were heat sealed to remove the opening. The officers laughed and told me the dogs would find them anyway. As it turned out, the drugs we used were sealed in foodsaver bags and then wrapped in a heavy canvas outer covering to protect the dogs from accidental exposure. I don't pretend to understand the intricacies of olfaction, but I developed a tremendous amount of respect for the dogs over the course of this study. Scent will find a way.

Bob Bankhead
(wandering_bob) - MLife

Locale: Oregon, USA
How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 08:10:53 MDT Print View

I'll be curious to see what the manufacturer of OP Sacks has to say - if anything.

Is it safe to assume you provided them with a courtesy copy of your article?

Thanks for your time. Please keep us advised.

Phillip Asby
(PGAsby)

Locale: North Carolina
Interesting on 04/10/2013 08:22:36 MDT Print View

I'll say it's things like this (and many others) that make BPL such a useful resource for a newbie like me - and by the responses for experienced backpackers as well!

This weekends trip with my sons Scout Troop is to Panthertown Valley, NC which is located within a NC designated black bear sanctuary and was subjec to a National Forest Service bear alert regarding some bears entering campgrounds and taking down bear bags.

I've been spending some time looking at bear safety myself, and our Troop has done a session on bear safety with the scouts. I have a bear canister I'll probably take along since I have it (UDAP No Fed Bear I got at STP for a good price with coupon) despite the weight. I'd been thinking about the odor sacks for my stuff as well given that the canister does nothing for odors and this article gives me pause to consider whether it is worth the effort.

Greg Mihalik
(greg23) - M

Locale: Colorado
Re: Interesting on 04/10/2013 08:30:16 MDT Print View

Phillip,

It is obvious that you will need a "Bag Handler" who has NO food/scent odors.

No foods in the pack.
Sitting 100 yards away during food prep and trailside lunches.
If this individual eats, s/he will have to be naked, and then take a bath.
I'm sure there are other considerations as well.

Best of Luck.

Edited by greg23 on 04/10/2013 08:32:06 MDT.

Craig W.
(xnomanx) - F - M
Interesting on 04/10/2013 09:07:42 MDT Print View

Thanks for confirming this. I've already had many very experienced thru-hikers tell me OPSAKs are useless...good to know it's not just speculation.

__________________________________________

I suspect you could've made a lot more money by forwarding this article to High Times Magazine instead of BPL. This info could potentially keep a lot of "entrepreneurs" out of trouble.

Ike Jutkowitz
(Ike) - M

Locale: Central Michigan
re: Entrepreneurs on 04/10/2013 09:11:17 MDT Print View

I asked the officers what would happen if the dogs couldn't find the bags. They told me that they would all buy stock in the company before the article got released.

Luke Schmidt
(Cameron) - MLife

Locale: The WOODS
Vacuum Sealed Bags? on 04/10/2013 09:14:37 MDT Print View

Did any of the officers mention people using vacuum sealed bags to fool dogs?

For lack of a better option I'm thinking I might vacuum seal individual meals and wash the outside of those meals very thoroughly. Obviously there will still be odor I'm just hoping it will be less odor then if I'd left a hunk of greasy summer sausage out.

For black bear I'm not too worried. Where I hike they are hunted and unlikely to bother me. Grizzly country would be the one place I'd go overboard with the whole vacuum sealing idea.

Stephen Barber
(grampa) - MLife

Locale: SoCal
Great job! on 04/10/2013 09:22:56 MDT Print View

Excellent work, Ari! I'm glad this research got published - it's just the kind of work that we need here on BPL!

I have a great deal of respect for dogs' scenting abilities, and seriously doubt that bears are any less able. Depending on "scent proof" bags is obviously not a viable technique for food safety in bear country.


Thanks again, and be sure to give your officers and dogs a big "Thank you!" from BPL!

John S.
(jshann) - F
Re: How Safe Is Your Food? Investigating the effectiveness of odor-proof bags on 04/10/2013 09:25:47 MDT Print View

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/50864