
High-Pressure Processing of Food - HillaryBriss
https://www.slideshare.net/zgoutham/high-pressure-processing-of-food
======
sandworm101
Pasteurization is one of the great lifesavers of the modern age, akin to the
initial use of fire to cook food. We in the west can afford to be obsessed
with "fresh" because, thanks to modern scientific agriculture, we don't have
to deal with so many pathogens. But the bugs are still out there. Cook your
food properly. I would be extremely cautious about any new sterilization tech.
I want it tested not just on clean food from clean farms, but on the horrible
stuff not normally seen in our food chains.

I like my steak overcooked, cooked to the point of wrecking it, because where
I grew up eating under-cooked meat was a serious health hazard. We used to
wash our vegetables in water with a bit of bleach. Whenever I see someone
eating a bloody steak, or vegetables rinsed only in tapwater, I shudder a
little.

Does it kill pork tapeworms?

[https://www.cbc.ca/radio/asithappens/as-it-happens-friday-
ed...](https://www.cbc.ca/radio/asithappens/as-it-happens-friday-
edition-1.5166570/brain-surgeons-went-looking-for-a-tumour-but-found-a-
tapeworm-instead-1.5166571)

"Some people get it by ingesting microscopic tapeworm eggs found in raw or
undercooked pork, or unwashed fruits and vegetables from overseas. But Palma
has never travelled outside the U.S."

~~~
blaze33
> where I grew up eating under-cooked meat was a serious health hazard.

This is a not-so-obvious fact I only learned about in my 20s : that everyday
food can be dangerous. I grew up in a very rural area and never thought our
food couldn't be safe (except the milk, we had to boil it once back back from
the farmer next door). I liked to eat bits of raw meat while my mother cooked
and always thought we rinsed the vegetables only because they taste and look
better without the dirt and small bugs.

Maybe I was lucky to live in a "safe food zone" (Europe, France). Is there any
data on the prevalence of food pathogens? Also, is there any correlation
between gut problems and being raised in rural vs. urban areas?

~~~
mistermann
I've never heard of home paseurizing farm milk, is that common?

~~~
gaustin
Yes. And easy. Though I would imagine not as common a practice as it was in
the past.

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asah
HPP is awesome: extends shelf life with minimal flavor/texture changes.
Favorite HPP product: "fresh" coconut water esp Harmless Harvest.

(I founded 3 successful food distribution startups)

~~~
skellera
I was wondering why harmless harvest tastes so much better than other coconut
water. It’s way too expensive for me to regularly buy but the flavor is so
much better.

~~~
psadri
Alas their green bottle lids are near impossible to twist open.

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crazygringo
Fascinating.

So why exactly is this not widespread now?

Is it too new, too costly, or does it diminish the taste/texture more than the
slides indicate?

Or is it just not necessary, e.g. most people either eat their food before it
goes bad, or forget about it for so long that this wouldn't make much a
difference anyways?

I have a hard time believing that subjecting, say, a crisp green pepper to
pressure high enough to disrupt all bacteria wouldn't noticeably alter the
texture (perhaps similar to how freezing does)... or just as bad, make it
implode and rupture. (Although I guess you could poke a small hole in produce
with hollow interiors.)

~~~
nextos
It's not that rare now. I have seen some mainstream dairies using it for
particular products distributed in EU. And many veggie smoothie brands use it
in the UK. E.g. Savse.

I would like to see studies comparing it to pasteurization as I said in
another comment. I believe pasteurization creates some denatured proteins and
weird peptides due to heat shock that might not be very healthy. It'd be
interesting to see whether HPP is better in this regard.

~~~
crazygringo
I'm no expert, but it seems like it would have to be better, no?

Pressure at these levels could damage cell walls but not break apart molecules
the way heat does, right?

~~~
nextos
That's the claim, and I tend to believe it's true. But I'd like to see some
convincing data.

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pfdietz
The effects of (very) high pressure on life are relevant to SETI, since it
probably rules out the existence of life deep in large water worlds, and in
"ice giants" like Uranus and Neptune.

At very high pressure, it becomes energetically favorable for proteins to be
broken down into individual amino acids. This is because amino acids are
zwitterions, with a positive and negative charged ends. These charged parts
pull in water molecules, which makes the Gibbs free energy of the reaction
more favorable for solvolysis as pressure goes up.

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Havoc
Noticed the same thing with pressure cookers. Food that has been nuked with
one will stay good at room temp for a surprising amount of time assuming no
additional exposure to contamination

~~~
askvictor
The point of a pressure cooker is to allow higher temperatures than 100°C,
which cooks things faster. But anything higher than 60°C should kill almost
all bacteria (possible exception: rice bacterial spores) if you cook it long
enough. Have you done a side-by-side comparison of food cooked in a pressure
cooker vs cooked at normal pressure?

~~~
Scoundreller
Killing spores is a lot harder. They can sit around in harsh conditions for a
few hundred years until the conditions are right to germinate. And cooked
foods devoid of other life (competition!) is a perfect situation.

There’s a lot floating through the air, not just what comes on rice.

For immediate consumption, it’s not usually necessary to kill them, but for
storage it can be.

~~~
ars
It won't stay a spore when wet though. The difficulty is when dry, but in
cooked food it's not going to stay in spore form.

That's why steam is used in medical sterilization, rather than just dry heat.

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exabrial
I'm a fan of irradiating food, but has never quite taken off.

Read through it all the way to see what it would do to beef, it looks like the
meat will lose its color.

~~~
NowThenGoodBad
At HPBB last year (coincidentally in Japan where high pressure food
sterilization was first commercialized) there was a whole series on high
pressure sterilization of food.

The last presentation was a company with a scalable automated canning and
sterilizing machine that was simply beautiful from an engineering standpoint.

Since we don't fully understand nutrients and how stuff like high pressure
sterilization, heating, and other methods affect bioavailability, impact
protein structure, and create other changes, it's all down to trying and
learning as we go.

What's great about pressure is that it can deactivate and destroy some of the
harmful organisms in food, but my curious concern is what does that do to the
cellular material we want intact for our body, how does that affect the
protein structure (for those not familiar, protein structure and folding is
absolutely crucial for functionality).

Irradiation concerns me more than pressure because if you're not careful, you
could be breaking bonds that you don't want to be breaking.

All in all it's a fascinating topic and important to everyone who eats.

~~~
wbl
You digestive system doesn't absorb intact protein but disintegrates it.

~~~
markdown
Look up variant Creutzfeldt-Jakob disease (aka Mad Cow Disease).

~~~
exabrial
Largely caused by animals being fed their own kind, but once the protein is
created, it's nearly impossible to destroy. It's denaturing temperature is
600+ degrees and it laughs in the face of irradiation. Id be curious if the
prion is susceptible to high pressure treatment

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londons_explore
Pressures so high they aren't found in nature create all kinds of denatured
proteins our digestive systems have never seen before. Most I'm sure won't do
much, but some might turn out to harm us in unseen ways.

Is nobody just a little worried about consuming all those without some more
serious safety tests first?

~~~
thereisnospork
No. proteins are denatured by cooking and the digestive process, before being
broken into constituent amino acids. It is both extremely unlikely that
applying pressure would create either novelly denatured proteins or that said
proteins, if formed, would be harmful.

The scenario isn't strictly impossible, but something reminiscent of an fda
phase 1 study to ascertain safety of every food item to undergo the procedure
is an insane standard[1]. Also a standard massively above and beyond anything
our current food supply has ever had in place.

[1] Read: costs of study far outweigh benefits weighted by likelihood and
severity of issue.

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nextos
It'd be nice to compare the effects of HPP vs Pasteurization in milk, and
whether it less disruptive.

Pasteurized milk doesn't ferment as well as raw milk, suggesting lots of
peptides are altered. And that is why some cheese DOPs mandate raw milk (only
on hard cheeses, as on soft ones it'd not be safe).

~~~
arcticbull
Fermentation is largely a product of naturally occurring bacteria is it not?
Makes sense pasteurizing it and killing them all would prevent fermentation,
which in this case would just be referred to as spoiling.

~~~
URSpider94
No, I think the point here is that even if you inoculate pasteurized milk with
microbes, which you typically do in cheese- or yogurt-making to ensure that
you grow the species you want, they still don’t grow as well nor produce the
same end product.

~~~
amluto
When I make yogurt, I usually hold the milk at a high temperature (> 180F) for
a while first — it improves the final texture. Raw is not necessarily better.

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hirundo
> Fresh or marinated meat: Iron in the myoglobin changes from ferrous to
> ferric and globin is denatured-the red color is lost.

For better or worse, it doesn't seem likely that the bioavailability is
identical between ferrous and ferric iron. How significant are such changes?
It'd be nice to see the results of some RCTs on rodents comparing this process
to fresh and heat treated. I imagine high pressure would be nutritionally
better or worse depending on the food.

Does anyone know if a 600 MPa pressure chamber, DIY or not, is within reach of
a garden variety prepper?

~~~
Hextinium
Considering that the yield strength of a lot of steels is at or below 600 MPa
I wonder what these machines are made out of. If you wanted to make one
yourself a 50 ton hydraulic press would generate the pressure needed but the
seals that you would need for this are crazy to be food safe.

Home canning would do almost the same effect for much cheaper.

~~~
hirundo
> A typical HPP process uses food products packaged in a high-barrier,
> flexible pouch or a plastic container.

If the pressure medium doesn't enter the pouch maybe it doesn't need to be
food safe.

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bufferoverflow
Diamond synthesis machines are at ~100 MPa. I wonder if these food ones are
capable of making gems without high temperatures.

~~~
mogadsheu
Unfortunately the pressure in HPP machines is dispersed over a large vessel
(foot scale diameter cylinders), while diamond anvil cells and the like focus
that pressure at the mm/sub-mm scale.

Would be nice though!

~~~
bufferoverflow
Why would that matter? High pressure is high pressure. Large vessel would mean
you can grow many diamonds at the same time, no?

~~~
mogadsheu
You might be right... pressure needed for diamond synthesis is almost
certainly much higher than for killing bacteria via pressure drop.

Turns out, it is, and they add temperature to the mix:

>They were able to heat carbon to about 3,000 °C (5,430 °F) under a pressure
of 3.5 gigapascals (510,000 psi) for a few seconds.

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anonu
Wouldn't the HPP process break the cell walls of the food being treated. This
would lead to poor tasting and faster deteriorating of the food?

Freeze drying is a process for preserving food which shares the high pressure
aspects of HPP. But apparently the pressure is not as high, and food can be
stored for 20 years.

~~~
grey413
Freeze drying is largely about removing water. No water means no bacterial
action. Instant mummification, in effect.

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amelius
By the way, there's also Pulsed Electric Field Pasteurisation.

[https://www.newfoodmagazine.com/article/2116/pulsed-
electric...](https://www.newfoodmagazine.com/article/2116/pulsed-electric-
field-pasteurisation-of-foods/)

------
PaulHoule
The other day I was thinking about the survivability of microbes inside ice
moons at various pressures and came across the the above topic.

It may well be that exomicrobes can be adapted to live at high pressures but
not be able to surive at low pressures.

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pwncake
I am assuming this is the same thing as Cold Pressure processing seen by this
hummus brand?
[http://www.bluemoose.com/about/](http://www.bluemoose.com/about/)

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jakobegger
This site is unreadable on mobile. Does anyone have a link to a PDF version?

~~~
NowThenGoodBad
Really? I had no problem on an iPhone X, swiped through the slides just fine.
What platform are you on?

~~~
fyfy18
It worked fine on a 6" device on Firefox for Android for me, however the text
was small, and when zooming it only shows the zoomed slides in the original
viewpoint which doesn't change.

I tested on an iPhone 5S which has a much smaller screen, so I need to zoom,
but when zooming the page ends up messed up.

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abetusk
Does anyone have a sense for how much the machines cost?

~~~
mattmaroon
Yes. I've looked into them for a project. They are very expensive. Like in the
low 7 figures. They're high maintenance and the packaging for at least some
foods required is relatively expensive too.

They're pretty much as this point only for large production
facilities/copackers. They're useful basically for products where heat-based
pasteurization has noticeable downsides.

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rbmktechik
We've been eating heat cooked food for millennia. We know it's more or less
safe, and we have evolved suitable enzymes.

We've never eaten stuff which went through such a high pressure process. This
is not your average pressure-cooker, look at the numbers.

We have no idea what eating this stuff does long term, just like micro-
plastics for example.

Yet people here seem to be cheering and jumping head-first just because it's
cool technology.

~~~
sneak
We can measure what it does. We can examine the inputs as well as the outputs.

Why are anti-science arguments from emotion/fear so common around new types of
food technology? What is it about food specifically that triggers what appears
to be a deep-seated fear of change in people?

~~~
colechristensen
Health has become a sort of religion for many. Health, food and religion
frequently go together in old mythology and now new.

"Good for you" and "bad for you" spread like old myth, factions fight, people
have incredibly strong beliefs sometimes which have at least a little basis in
reality sometimes they are worse than harmless.

These days it just isn't because some mystical being said so.

