A freshness indicator comprises a support structure that is substantially impermeable to fluids. A test device is engaged with the support structure and includes a pathogen detection composition. The pathogen detection composition provides a prescribed visual indication when in the presence of a prescribed type of pathogens and/or a by-product thereof. A flow limiting structure extends over the test device and has an entire perimeter edge portion thereof attached to the support structure in a manner whereby the flow limiting structure and the support structure jointly form a fluid resistant interface around a space in which the test device resides. The flow limiting structure substantially allows a portion of the prescribed type of pathogen and/or a portion of the by-product thereof to enter the space in which the test device resides and substantially inhibits any portion of the pathogen detection composition from escaping from the space in which the test device resides.
新鲜度指示器包括一个基本上不透
水的支撑结构。测试装置与支撑结构相连,并包括一种病原体检测组分。当存在规定类型的病原体和/或其副产物时,病原体检测组分会提供一种规定的视觉指示。流量限制结构延伸至测试装置上,并具有其整个周边边缘部分连接到支撑结构上,以使流量限制结构和支撑结构共同形成一个围绕测试装置所在空间的液体阻抗界面。流量限制结构基本上允许规定类型的病原体和/或其部分副产物进入测试装置所在的空间,并且基本上抑制病原体检测组分的任何部分从测试装置所在的空间中逸出。