真(zhen)空(kong)包(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)中重(zhong)要的其(qi)一環(huan)節是除氧(yang)，有利于防止食(shi)品(pin)變(bian)(bian)(bian)質，其(qi)原(yuan)理(li)也(ye)比較簡單，因食(shi)品(pin)霉(mei)腐變(bian)(bian)(bian)質主(zhu)要由微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)的活(huo)動造成， 而大多數微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)（如霉(mei)菌(jun)和(he)(he)酵母菌(jun)）的生(sheng)(sheng)(sheng)存(cun)是需(xu)要氧(yang)氣(qi)(qi)的，而真(zhen)空(kong)包(bao)裝(zhuang)(zhuang)(zhuang)(zhuang) 就是運用這個原(yuan)理(li)，把(ba)包(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋(dai)內(nei)和(he)(he)食(shi)品(pin)細(xi)胞內(nei)的氧(yang)氣(qi)(qi)抽掉，使微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)失去“生(sheng)(sheng)(sheng)存(cun)的環(huan)境”。實驗證明(ming)：當包(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)袋(dai)內(nei)的氧(yang)氣(qi)(qi)濃度(du)≤1%時， 微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)的生(sheng)(sheng)(sheng)長(chang)和(he)(he)繁殖(zhi)(zhi)速度(du)就急劇下(xia)降，氧(yang)氣(qi)(qi)濃度(du)≤0．5%，大多數微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)(wu)(wu)將受到抑制而停止繁殖(zhi)(zhi)。（注：真(zhen)空(kong)包(bao)裝(zhuang)(zhuang)(zhuang)(zhuang)不能抑制厭氧(yang)菌(jun)的繁殖(zhi)(zhi)和(he)(he)酶反應引起的食(shi)品(pin)變(bian)(bian)(bian)質 和(he)(he)變(bian)(bian)(bian)色(se)，因此還需(xu)與其(qi)他輔助(zhu)方(fang)法結合，如冷藏、速凍、脫水、高溫殺菌、輻照滅菌、微波殺菌、鹽腌制等(deng)。