Food preservation
Table of Contents
prevents the growth of microorganisms (such as yeasts), or other microorganisms (although some methods work by introducing benign bacteria or fungi to the food), as well as slowing the oxidation of fats that cause rancidity. Food preservation may also include processes that inhibit visual deterioration, such as the enzymatic browning reaction in apples after they are cut during food preparation.
Many processes designed to preserve food involve more than one food preservation method. Preserving fruit by turning it into jam, for example, involves boiling (to reduce the fruit’s moisture content and to kill bacteria, etc.), sugaring (to prevent their re-growth) and sealing within an airtight jar (to prevent recontamination). Some traditional methods of preserving food have been shown to have a lower energy input and carbon footprint, when compared to modern methods.[1]
Maintaining or creating nutritional value, texture and flavor is an important aspect of food preservation.
https://en.wikipedia.org/wiki/Food_preservation
Traditional Food Preservation Techniques
Cooling/Freezing
– We do it every day, as we hear the refrigerator to jump into action
Heating/Boiling
– Much as with the Fridge, we do it every day when we turn on the stove
Air Drying/Dehadrating
– Dries the food with the influence of moving air and temperature, stopping enzymatic action extracting moisture to minimize spoilage
Curing
– Is the preservation through salting food extensively. Salt draws the moisture out of the food via osmosis, eliminating the organic space in which pathogens can grow.
Sugaring
– Is the process of dehydrating a food, then packing it with pure sugar, Honey, Syrup or Molasses to keep it from spoiling. Too much moisture in the process will attract natural yeasts over time and start a fermentation
Jarring/Canning
– Uses low-high heat, pressure and time for specific durations, to eliminate and sterilize food contentment. This can is done in an autoclave/pressure cooker at 15psi for 20 min or through pasteurization processes. Ultra High Heat at 275F for 1-2 seconds, high heat 151F for 15 sec., or at 145F for 30 min.
Pickling/Fermenting
– Happens through symbiotic cultures of bacteria and yeast (SCOBY). In the process the food is submerged in a 2% salt brine, to stop food from further decay. Over time yeast and bacteria will feed of the carbohydrates creating the pickle and sauerkraut juice as we know it adding live cultures of probiotics in the process.
Jellying/Aspic
– Meats and vegetable are preserved inside a jelly/galantine cake to eliminate oxygen and as such the spoilage of the food preserved.
Acidity/Alkalinity Preservation
– Is used to alter the Ph content of the liquid inside the food making it inhabitable for microorganism so thrive. Lemon juice is used on apples to stop enzymatic browning by lowering the Ph. Where olives are preserved by adding Sodium hydroxide (lye) to the brine making food too alkaline for bacterial growth.
Hot/Cold Smoking
– Relies on the evaporation of compounds in the smoke such as formaldehyde and alcohols which have preserving properties. Smoke dries the cured meat slowly closing the meats pores which hold in the juices in. Cold smoking needs extended amounts of time and low heat, where as hot smoking integrated the aspect of heat, killing all pathogens in the process.
Wood Ash Preservation
– Incorporates the aspect of eliminating oxygen and moisture at the same time. Cherokees used wood ash to preserve meats, norweigians for fish, as do some tribes in Africa to this day.
Burial/Root Cellar Preservation
– Is the old equivalent to our modern cooling and freezing. Holes or root cellars were dug to make use of the geothermal properties of earth’s environment and temperature which lays steadily between 45F and 55F.
Summary:
To sum it up; Food preservation methods are often times used in combination to make them work best. The main aspect is the elimination of environmental thresholds by either killing all pathogens with heat and stopping microorganism from multiplying in cold environments, taking away the moisture, or Oxygen; or reducing or increasing the “power of hydrogen (Ph)”.
All these principles take away the environment microorganism need to live.
