凍(dong)(dong)(dong)肉(rou)、凍(dong)(dong)(dong)魚、凍(dong)(dong)(dong)蝦等冷凍(dong)(dong)(dong)食(shi)(shi)品,在(zai)解(jie)凍(dong)(dong)(dong)后應(ying)馬上烹制(zhi),但(dan)現實生活中常有這種情況:解(jie)凍(dong)(dong)(dong)后的(de)(de)食(shi)(shi)品一時吃不(bu)完,又重新放入冰(bing)箱冷凍(dong)(dong)(dong)貯藏(zang)。這種做法對食(shi)(shi)品的(de)(de)營養(yang)(yang)價(jia)值和(he)新鮮度影響較(jiao)大。因食(shi)(shi)品經過反復(fu)冷凍(dong)(dong)(dong)和(he)解(jie)凍(dong)(dong)(dong),細(xi)胞膜受到(dao)較(jiao)多的(de)(de)損壞,細(xi)胞汁液大量流(liu)失,造(zao)成營養(yang)(yang)成分和(he)可溶性呈味成分損失較(jiao)多,影響了食(shi)(shi)品原有的(de)(de)鮮味和(he)風味,營養(yang)(yang)價(jia)值也(ye)隨之降低。
由(you)于冷凍(dong)食品(pin)經過解凍(dong),溫度回升,就可能為(wei)細菌(jun)(jun)和(he)霉菌(jun)(jun)的生長(chang)、繁殖提(ti)供了(le)條(tiao)件,食品(pin)很(hen)容(rong)易腐(fu)敗變質。據有關(guan)研(yan)究表明,食品(pin)再次冷凍(dong)、解凍(dong),特別是反復多次的冷凍(dong)、解凍(dong),還容(rong)易產生有毒物質,對人體健康危害(hai)較大。
為(wei)了(le)保證冷(leng)(leng)凍食(shi)品質量,以(yi)小包裝形(xing)式包裝冷(leng)(leng)凍食(shi)品為(wei)好(hao),這樣(yang)就可以(yi)避(bi)免發生食(shi)品解凍后用不完而再次冷(leng)(leng)凍貯藏的情況。