Scanning electron microscopy of food items using a variable-pressure SEM

Scanning electron microscopy generally requires specimen preparation which includes dehydration or drying and metal coating. This preparation is necessary for beam sensitive specimens or specimens that contain water and/or oil. This has been a necessary requirement for quality imaging with conventional scanning electron microscopes (SEMs). Recently with the development of variable-pressure SEMs (VP-SEMs), scanning electron microscopy of most specimens has become possible without the need of specimen preparation. Water-containing wet specimens can be examined at low temperatures at which water vaporization is suppressed and specimen artifacts due to water evaporation are minimized.