Читать книгу Analytical Food Microbiology - Ahmed E. Yousef - Страница 37

Surfaces in processing facilities are commonly designated by their likelihood to cause food contamination. Food contact surfaces (Zone 1) are important sites that are often considered during environmental sampling. A food contact surface could be part of a piece of equipment, packing material, storage tank, ripening room, conveyer belt, or any other item that is expected to touch the food item. Zone 2 is an area where surfaces do not directly contact food but are usually located in the same room as those of zone 1. If zone 2 is contaminated with pathogens, it is likely that zone 1 also becomes contaminated. Contaminant transfer is often caused by human or machine action. Surfaces in zone 2 include walls or floors located near processing equipment and overhanging pipes or equipment. Zone 3 is an area that may cause contamination of zone 2. Zone 3 includes warehouses, employee locker rooms, and loading docks. Listeria monocytogenes is an example of pathogens that are commonly transmitted to food from the processing environment.

Sampled surfaces could be rough or smooth, flat or with curves and corners, continuous or with cracks and crevices, and accessible or difficult to reach. Therefore, the choice of a method to sample a surface depends not only on the surface zone but also on its characteristics.