Forum: cooking.stackexchange.com
Tags: <food-preservation>
Title: Is there any way to kill bacteria in food without using heat?
Question: The title says it all. Context: food preservation

Answers:
sents: text: As Lars Friedrich already wrote, curing with salt is a way to kill bacteria.
text: A high sugar content and the removal of water in general alters the water activity .
text: 1
text: Some chemicals are toxic to bacteria (and to some extend also toxic to humans) like borax (which is used to preserve caviar; I'm not sure if it only inhibits the growth of bacteria) or ethanol (drinking alcohol).
text: Sulfites are used - not exclusively - in wine making and on dried fruit.
text: You can alter the pH .
text: I doubt the food will be edible as-it-is.
text: Last but not least you can irradiate the food to sterilize it.
text: Irradiation is also commonly used to sterilize (disposable?) medical equipment.
text: Please note that freezing does not kill any bacteria.
text: Side note: There are some other bacteria that survive even in such adverse environments but they are not common as foodborne pathogens.
text: If you really want to be sure that the food is sterile without cooking, you have pressure-sterilize, "poison" it or irradiate it.
text: You can also preserve food even with bacteria and fungi: A sourdough has an almost indefinitely shelf-live.
text: It basically only consists of flour, water and a mix of many different bacteria and yeasts.
text: Cultured milk also has a very long shelf life.
text: For further reading: The FAT TOM rule describes the six favorable conditions required for the growth of foodborne pathogens. 1 Caveat:
text: (Botulinum) spores survive in honey.
text: Do they count as bacteria?
answer_details: author: cooking.stackexchange.com/users/23376/Ching Chong
score: 7
sents: text: The most common method to kill bacteria without heat is curing with salt.
text: The removal of the water and the addition of salt leads to an osmotic pressure that draws the water out of the bacteria.
answer_details: author: cooking.stackexchange.com/users/39427/John Hammond
score: 4
sents: text: The term is "cold sterilization"; most methods will indeed be out of reach of home users.
text: Some of the methods used in industry seem to be just sieving the bacteria out (microfiltration), pressurizing everything to 50000 psi, or obviously chemicals that remain in the food as preservatives or that self-decompose into relatively inert compounds in storage (Dimethyldicarbonate).
text: Some compounds in common seasonings (Turmeric, Onions/Garlic, Chilies) are claimed to have an effect that lowers bacterial growth (but does not completely inhibit it).
answer_details: author: cooking.stackexchange.com/users/35312/rackandboneman
score: 4
sents: text: Classic sour pickles actually contain a very small amount of salt -- just enough to discourage most bacteria and encourage the growth of Lactobacillus acidophilus.
text: LBA's byproducts then kill off whatever else was trying to compete with it.
text: Vinegar pickles likewise are a hostile environment for most organisms.
text: (Folks not too much younger than me can remember when stores had barrels of pickles and you'd just grab the ones you wanted with a pair of tongs.
text: No refrigeration needed.)
text: Other folks have covered other traditional ways of preserving food -- drying, smoking, etc.
text: A properly cured ham can hang on a hook for years and still be edible, though you may need to trim off the moldy outer surface.
text: While we're speaking of mold: cheese is another food protected by curing, using various cultures.
text: And again, if you don't mind trimming off the rind, many hard cheeses can pretty much look after themselves.
text: So can butter, actually
text: -- it may go rancid due to chemical breakdown if not kept cool, but other than that it doesn't need to be refrigerated.
text: Ditto most oils.
text: Ditto most fruit; it may get moldy or start to ferment due to harmless organisms, but otherwise can look after itself longer than most Americans think it can.
answer_details: author: cooking.stackexchange.com/users/24888/keshlam
score: 1
sents: text: Certain viruses can be used : In the Federal Register of August 18, 2006, FDA announced that it had approved the use of a bacteriophage preparation made from six individually purified phages to be used on RTE meat and poultry products as an antimicrobial agent against Listeria monocytogenes.
answer_details: author: cooking.stackexchange.com/users/25893/Count Iblis
score: 1
sents: text: In Home-settings; our family do as the following - For meat => Use Lemons or limes - Just simply slice the lemons and squeeze it over the meat in a bowl. - Leave it for 15 minutes or more (can also refrigerated for overnight if you wish to prepare for another day) For vegetable =
text: >
text: Use salt - In a bowl of water, add some amount of salt - Then, add vegetable (after cut) - Leave it for 15 minutes or more
text: I hope that's what you are looking for.
text: Thanks.
answer_details: author: cooking.stackexchange.com/users/40824/Nai
score: 1
sents: text: Hydrogen peroxide (H2O2) is used to treat liquids such as milk and stored water.
text: Only a couple of drops of 3-7% aqueous solution of H2O2 in 1L of liquid is enough to disinfect.
text: Fresh milk could last 2 weeks easily when treated.
answer_details: author: cooking.stackexchange.com/users/29278/cataltar
score: 0

Summary of the answers:
Salt, vinegar and other chemicals like borax, ethanol, sulphites and hydrogen peroxide can be used to preserve food, often by making an environment hostile to bacteria and other unwanted elements. Altering the pH, irradiating the food, cold sterilisation, drying, smoking, curing and even bacteria and viruses can also be used to preserve food using tratitional and modern means, but not all of these will be available to home cooks.
Natural methods of killing bacteria include include curing, pickling, drying and smoking. Chemicals may also be used or the food may be irradiated. It should be noted that freezing does not kill bacteria. On the other hand, some foods are preserved with bacteria, like sourdough. Cold sterilization and use of viruses are not really available to home users.