真空袋(dai)主(zhu)要作用是(shi)除(chu)氧(yang)，以(yi)有(you)利于防(fang)止食(shi)品(pin)變質(zhi)，其原(yuan)理也比較簡單，因食(shi)品(pin)霉(mei)腐(fu)變質(zhi)主(zhu)要由微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)的活動(dong)造成，而大(da)多數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)（如霉(mei)菌和酵母菌）的生(sheng)(sheng)(sheng)(sheng)存是(shi)需要氧(yang)氣(qi)的，而真空包裝(zhuang)就(jiu)是(shi)運用這個(ge)原(yuan)理，把(ba)包裝(zhuang)袋(dai)內(nei)和食(shi)品(pin)細(xi)胞內(nei)的氧(yang)氣(qi)抽掉，使微(wei)(wei)物(wu)物(wu)失去“生(sheng)(sheng)(sheng)(sheng)存的環(huan)境”。實驗(yan)證明：當(dang)包裝(zhuang)袋(dai)內(nei)的氧(yang)氣(qi)濃度(du)≤1%時，微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)的生(sheng)(sheng)(sheng)(sheng)長和繁(fan)殖速(su)度(du)就(jiu)急劇(ju)下(xia)降，氧(yang)氣(qi)濃度(du)≤0.5%時，大(da)多數微(wei)(wei)生(sheng)(sheng)(sheng)(sheng)物(wu)將(jiang)受(shou)到抑制而停止繁(fan)殖。