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The truth about canning
罐頭為什么保質期這么長？
During the mid-19th century, canned food became a status symbol among middle-class households in Europe, being something of a frivolous novelty.
在19世紀中葉，罐頭食品作為一種令人著迷的新鮮事物，成為歐洲中產階級家庭的地位象征。
Increasing mechanization of the canning process, coupled with a huge increase in urban populations across Europe, resulted in a rising demand for canned food.
罐頭加工技術的提高，加上城市人口的大幅增加，導致歐洲對罐頭食品的需求不斷增長。
A number of inventions and improvements followed, and by the 1860s, smaller machine-made steel cans were possible, and the time to cook food in sealed cans were reduced from around six hours to 30 minutes.
許多的發明和改進隨之而來。到 1860 年代，小機器制造的鋼罐也投入使用，而加工密封罐裝食物的時間從大約六個小時減少到三十分鐘。
To prevent the food from being spoiled before and during containment, a number of methods are used: pasteurization, boiling (and other applications of high temperature over a period of time), refrigeration, freezing, drying, vacuum treatment, antimicrobial agents that are natural to the recipe of the foods being preserved, a sufficient dose of ionizing radiation, submersion in a strong saline solution, acid, base, osmotically extreme (for example very sugary) or other microbially challenging environments.
為了防止食品在密封之前和密封期間變質，人們使用了許多方法：巴氏殺菌、煮沸（以及其它在單位時間內達到高溫的手段）、冷藏、冷凍、干燥、真空處理、使用對保存食品配方天然的抗菌劑、足夠劑量的電離輻射、將食物浸入強鹽溶液中、或使用酸、堿滲透極端環境（例如非常含糖）或其他微生物難以生存的環境。
Other than sterilization, no method is perfectly dependable as a preservative. For example, the spores of the micro-organism Clostridium botulinum (which causes botulism) can be eliminated only at temperatures above the boiling point of water.
除了滅菌之外，沒有任何方法能像加防腐劑一樣完全可靠。例如，微生物肉毒梭菌（引起肉毒桿菌中毒）的孢子只能在高于水沸點的溫度下消除。
本文轉載自中國日報網，如有侵權，請聯系我們刪除。
