Temperature zones 温度范围 BoilingPoint 沸点 100° SAFETY PasteurisingTemperature 安全温度 72° 巴氏天菌温度 60° BodyTemperature DANGER 体温 36.5° 之危险温度 Fridge冷藏箱 10 ° SAFETY Freezer冷冻 安全温度 16 窗
16 0° 10° 36.5° 60° 72° 100° BoilingPoint 沸点 PasteurisingTemperature 巴氏灭菌温度 Freezer 冷冻 Fridge 冷藏箱 BodyTemperature 体温 Temperature zones 温度范围 SAFETY 安全温度 SAFETY 安全温度 DANGER 危险温度
Psychro trophic pathogens 嗜冷致病菌 L.monocytogenes 单核细胞增生李斯特菌 Y.enterocolitica 小肠结肠炎耶尔森氏菌 >C.botulinum type 肉毒梭状芽孢杆菌 17 窗
17 Psychro trophic pathogens 嗜冷致病菌 ➢ L . monocytogenes 单核细胞增生李斯特菌 ➢ Y . enterocolitica 小肠结肠炎耶尔森氏菌 ➢ C . botulinum type 肉毒梭状芽孢杆菌
Water activity 水分活度 >Water is required for the growth and metabolism of microorganisms 水是微生物生长和新陈代谢必需的物质 All the water in foods is not available for microorganisms 并非食品中的水分都能被微生物利用 The degree of availability of water is measured by water activity (a w) 用水分话度āw衡量有效水分的含量 Chemical and enzymatic reactions are also affected by availability of water 化学反应和酶反应也受有效水分的影响 18 窗中
18 ➢ Water is required for the growth and metabolism of microorganisms 水是微生物生长和新陈代谢必需的物质 ➢ All the water in foods is not available for microorganisms 并非食品中的水分都能被微生物利用 ➢ The degree of availability of water is measured by water activity (a w ) 用水分活度a w 衡量有效水分的含量 ➢ Chemical and enzymatic reactions are also affected by availability of water 化学反应和酶反应也受有效水分的影响 Water activity 水分活度
Water activity (definition) 水分活度a的定义 a w is the ratio of water vapour pressure of food(p)to that of pure water(p)at the same temperature. w指相同温度下，食品的水蒸汽压P和纯水的蒸 汽压P0之比。 aw=plpo 0<aw<1 9 窗
19 a w is the ratio of water vapour pressure of food (p) to that of pure water (po ) at the same temperature. a w指相同温度下，食品的水蒸汽压P和纯水的蒸 汽压P0之比。 a w = p/ po 0 < a w < 1 Water activity (definition) 水分活度a w的定义
Vater activity(3)水分话度aw Reaction rate 反应速率 Growth of: Lipid oxydation油脂氧化 Moulds霉菌 Yeasts酵母 Bacteria细菌 Enzymatic activity 酶的活力 Non-enzymatic Browning非酶羯变 0.10.20.30.40.50.60.70.80.9 A 窗田
20 Water activity (3) 水分活度a w 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Aw Reaction rate 反应速率 Lipid oxydation 油脂氧化 Non-enzymatic Browning 非酶褐变 Enzymatic activity 酶的活力 Growth of: Moulds 霉菌 Yeasts 酵母 Bacteria 细菌