Gill C O, Penney N
Meat Industry Research Institute of New Zealand (Inc.), PO Box 617, Hamilton, New Zealand.
Meat Sci. 1988;22(1):53-63. doi: 10.1016/0309-1740(88)90026-5.
Normal pH (5·5-5·7) and high pH (>6·0) beef cuts of 400 g were vacuum packaged in polyvinylidine chloride (PVDC) laminate, in aluminium foil laminate or in foil laminate with a CO(2) scavenger (Ba(OH)(2)); or were packaged under CO(2) in foil laminate with CO(2) added at 200, 400, 700, 1000 or 2000 ml per kg of meat. The process used to prepare meat before packaging resulted in an initial flora containing a high fraction of eneterobacteria but with undetectable numbers of lactobacilli. During storage at +1°C, all vacuum packaged meat developed floras containing substantial fractions of enterobacteria. The enterobacteria fractions were larger on high pH than on normal pH meat, and on normal pH meat in PVDC or in foil laminate plus CO(2) scavenger packs than on normal pH meat in foil laminate without the CO(2) scavenger. All vacuum packaged meat was spoiled by putrid flavours, high pH meat at 7 weeks and normal pH meat at 12 weeks. Increasing amounts of added CO(2) progressively retarded the development of putrid spoilage, as growth of the spoilage floras was slowed while the relative numbers of lactobacilli in the floras were enhanced. With the two largest amounts of added CO(2), spoilage was delayed until 15 weeks and 21 weeks for high pH meat and normal pH meat, respectively, and enterobacteria were detected in the spoilage floras only at later sampling times. With lesser amounts of added CO(2), enterobacteria persisted or re-emerged at earlier times, in the floras.
将400克正常pH值（5.5 - 5.7）和高pH值（>6.0）的牛肉块用聚偏二氯乙烯（PVDC）层压板、铝箔层压板或带有二氧化碳清除剂（氢氧化钡）的箔层压板进行真空包装；或者在二氧化碳环境下，用添加了每千克肉200、400、700、1000或2000毫升二氧化碳的箔层压板进行包装。包装前用于制备肉类的过程导致初始菌群中肠杆菌比例较高，但乳酸菌数量检测不到。在1℃储存期间，所有真空包装的肉类都形成了含有大量肠杆菌的菌群。高pH值肉类上的肠杆菌比例高于正常pH值肉类，正常pH值肉类在PVDC或带有二氧化碳清除剂的箔层压板包装中的肠杆菌比例高于没有二氧化碳清除剂的箔层压板包装的正常pH值肉类。所有真空包装的肉类都因腐臭味而变质，高pH值肉类在7周时变质，正常pH值肉类在12周时变质。增加二氧化碳的添加量逐渐延缓了腐臭变质的发展，因为变质菌群的生长减缓，而菌群中乳酸菌的相对数量增加。添加量最大的两种二氧化碳情况下，高pH值肉类和正常pH值肉类的变质分别延迟到15周和21周，并且仅在后期采样时在变质菌群中检测到肠杆菌。添加量较少的二氧化碳情况下，肠杆菌在菌群中更早持续存在或重新出现。
