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High-Pressure Processing of Food
- hirundo 7y ago> 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?
- mattmaroon 7y agoThe machinery is very expensive and DIYing something with those pressures is very dangerous, since you're building a bomb. That's about 2000x the pressure inside a champagne bottle and 20x the pressure of a bomb.
- aaronblohowiak 7y agoFor reference the Max cylinder pressure in an ice vehicle is 20 MPa iirc
- Hextinium 7y agoConsidering 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 7y ago> 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.
- petra 7y agoFor DIY, micvac.com is safe and may fit to the meal-prep community very well. The basic idea is a single-use valve based plastic package that lets you cook the food in a microwave in a closed container with an open valve(for steam release), but once it starts cooling, the valve closes,all bacteria are dead, the steam inside the package than condenses , creating low-pressure inside the package, similar to vacuum packing. They describe the tech in their site, and in their patents. Diy for it seems tough, you have engineer the right valve and package to ensure that every food, in every microwave , will get sterilized by the heat.
- PaulHoule 7y agoThe 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.
- exabrial 7y agoI'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 7y agoAt 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.
- petra 7y agoWhat about microwave assisted sterlization, or similarly , micvac.com(a in package cooking where a valve released all air, and than created negative pressure to make the package vacuum sealed) ? Why aren't they more common in ready meals ?
- wbl 7y agoYou digestive system doesn't absorb intact protein but disintegrates it.
- markdown 7y agoLook up variant Creutzfeldt-Jakob disease (aka Mad Cow Disease).
- Havoc 7y agoNoticed 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
- joezydeco 7y agoOur grandmothers canned countless jars of summer fruit and vegetables this way.
- cardamomo 7y agoI even find that leftovers from meals I've cooked in a pressure cooker last quite a long time in the fridge.
- raverbashing 7y agoPressure cookers have a much lower pressure (~2atm) than what's happening here
- askvictor 7y agoThe 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 7y ago
- jakobegger 7y agoThis site is unreadable on mobile. Does anyone have a link to a PDF version?
- jwilk 7y agohttps://www.docdroid.net/file/download/1gE4Jhw/tdxsd5ty.pdf https://www.docdroid.net/file/download/1gE4Jhw/tdxsd5ty.pdf
- NowThenGoodBad 7y agoReally? I had no problem on an iPhone X, swiped through the slides just fine. What platform are you on?
- fyfy18 7y agoIt 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.
- jakobegger 7y agoAlso on iPhone X. When zooming the layout becomes garbled and unreadable.
- crazygringo 7y agoFascinating. 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 7y agoIt'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 7y agoI'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 7y agoThat's the claim, and I tend to believe it's true. But I'd like to see some convincing data.
- sirteno 7y agoIt’s been widely used in the soft drinks and dairy sector for at least 5 years now. I was involved in a UK-based “cold pressed” juice business and we used HPP to extend shelf life of our drinks from 2-3 days to 20-25 days (depending on the ingredients). This was 2013-2015 and there were already facilities who would batch HPP products for companies like ours.
- nextos 7y agoIt'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 7y agoFermentation 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.
- nextos 7y agoAbsolutely, but if you add plenty of starters to pasteurized milk you can get nice fermentation. That's what most cheese producers do. Pasteurize and then ferment. What I meant is that differences arising in fermentation processes of raw vs pasteurized milk may not be just due to the microbial populations present before adding more microbial starters. But also because pasteurization "damages" some proteins and lipids, which can't be subsequently processed by bacteria.
- URSpider94 7y agoNo, 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 7y agoWhen 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.
- semi-extrinsic 7y ago> only on hard cheeses, as on soft ones it'd not be safe Actually that's not true. This is pretty much only a thing in the US. All across Europe you can get soft unpasteurized cheeses in any large supermarket with a good cheese selection. Stuff like Brie de Meaux, Reblochon, or the Belgian Herve, or even proper Camembert falls in this category.
- asah 7y agoHPP 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 7y agoI 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 7y agoAlas their green bottle lids are near impossible to twist open.
- equalunique 7y agoThat stuff is the best coconut water money can buy in North America.
- bufferoverflow 7y agoDiamond synthesis machines are at ~100 MPa. I wonder if these food ones are capable of making gems without high temperatures.
- mogadsheu 7y agoUnfortunately 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 7y agoWhy would that matter? High pressure is high pressure. Large vessel would mean you can grow many diamonds at the same time, no?
- mogadsheu 7y agoYou 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.
- lostmyoldone 7y agoThe high pressure high temperature synthesis (HPHT) use pressures from 5GPa and up, but as the slides talk about 600MPa as a useful pressure the difference is "only" a factor 10. One additional issue with diamond synthesis with the HPHT is that you need 1400°C, and the correct mix of graphite and metallic catalysts.
- abetusk 7y agoDoes anyone have a sense for how much the machines cost?
- mattmaroon 7y agoYes. 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.
- rbmktechik 7y agoWe'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.
- steve19 7y agoAs far as I can tell it simply kills larger cells like bacteria and deactivates plant/fungus spores. It is not cooking the food. I would not think it could do much, beyond maybe introducing more micro-plastics (the deck mentioned vacuum packaging food before being pressurized).
- harimau777 7y agoEven though we don't have long term experience the way we do with cooking, the description of the process on Wikipedia seems to suggest that it doesn't have much in the way of chemical effects on food. I'm definitely not an expert, and this is just an initial take, but I don't really see any mechanisms that could plausibly be dangerous. In order to illustrate what I mean by a way that something could plausibly be dangerous: My understanding is that the molecules in most plastics contain chemicals that are known to be harmful. So even if we determine that it is not possible for them to break down into harmful chemicals in the body, it was plausible that they might. Am I maybe missing some what that this process could be harmful?
- rbmktechik 7y agoThey explicitly state that they don't really know how it affects proteins, only that they are changed in "complex" ways. Here is one example of a protein change which is deadly: https://en.wikipedia.org/wiki/Prion https://en.wikipedia.org/wiki/Prion
- burfog 7y agoThe pressure may cause the container to release molecules into the food. Plastic that is normally considered food-safe might not be food-safe at these pressures.
- sandworm101 7y agoPasteurization 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-edition-1.5166570/brain-surgeons-went-looking-for-a-tumour-but-found-a-tapeworm-instead-1.5166571 https://www.cbc.ca/radio/asithappens/as-it-happens-friday-ed... "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 7y ago> 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 7y agoI've never heard of home paseurizing farm milk, is that common?
- gaustin 7y ago
- londons_explore 7y agoPressures 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 7y agoNo. 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.
- mogadsheu 7y agoIt’s extremely common—I visited an HPP facility and all kinds of food from deli meat to fresh juice were being processed. The same can be said for heat treating (i.e. cooking). That said, I agree that food processing isn’t completely charted territory.
- amelius 7y agoBy the way, there's also Pulsed Electric Field Pasteurisation. https://www.newfoodmagazine.com/article/2116/pulsed-electric-field-pasteurisation-of-foods/ https://www.newfoodmagazine.com/article/2116/pulsed-electric...
- anonu 7y agoWouldn'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 7y agoFreeze drying is largely about removing water. No water means no bacterial action. Instant mummification, in effect.
- pfdietz 7y agoThe 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.
- pwncake 7y agoI 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/