真空(kong)(kong)袋主(zhu)要(yao)作用(yong)是除氧，以有利于防止食品變(bian)質，其原理也(ye)比較(jiao)簡(jian)單，因食品霉(mei)腐(fu)變(bian)質主(zhu)要(yao)由微(wei)(wei)生(sheng)(sheng)(sheng)物的活動造成(cheng)，而(er)大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物（如霉(mei)菌(jun)和酵母菌(jun)）的生(sheng)(sheng)(sheng)存(cun)是需要(yao)氧氣的，而(er)真空(kong)(kong)包(bao)裝(zhuang)就(jiu)是運用(yong)這個(ge)原理，把包(bao)裝(zhuang)袋內和食品細胞內的氧氣抽掉，使微(wei)(wei)物物失去“生(sheng)(sheng)(sheng)存(cun)的環(huan)境”。實(shi)驗證(zheng)明：當包(bao)裝(zhuang)袋內的氧氣濃(nong)度≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)物的生(sheng)(sheng)(sheng)長和繁殖速度就(jiu)急劇下降，氧氣濃(nong)度≤0.5%時，大多(duo)數微(wei)(wei)生(sheng)(sheng)(sheng)物將受到抑制(zhi)而(er)停止繁殖。