Food Protection Trends - July 2009 - 441

TABLE 4. dry cleaning Types of cleaning in a low-moisture product manufacturing facility no water is used. dry cleaning is the physical removal of residues (food particles, dust, etc.) by actions such as sweeping, brushing, scraping, or vacuuming the residues from equipment surfaces and the plant environment. Water can be applied. However, certain practices should be avoided, e.g., excessive use of water (floor is flooded with water), high pressure hoses. Instead, water should be used on an as-needed basis and should be minimized and isolated to specific areas where possible. Complete drying after the wet cleaning is essential. a limited amount of water is used. Complete drying must follow immediately after the controlled wet cleaning. Specific pieces of equipment may be moved out of the Primary Salmonella Control area, wet cleaned, sanitized, dried and then returned. Wet cleaning Controlled wet cleaning the manufacture of foods is accomplished by processes within areas of the manufacturing facility with differing requirements for water. the requirement for water during processing or sanitation typically defines the equipment and process hygienic design standards. these differing design standards do not reflect a lower hygienic expectation, but rather the appropriate approach to maintaining the equipment and process in a hygienic state, given the risk that water presents in terms of microbial growth. the equipment, surroundings and infrastructure that remain in a dry state (e.g., grain silos, dry blending, chocolate processing) generally will not be exposed to water and therefore have design standards that differ from the standards of equipment requiring water for food processing or sanitation. because limiting water is the primary means of controlling Salmonella in low-moisture food manufacturing, it is imperative that the relationship of each process point and installation to water sources be evaluated. Simply put, the type of cleaning necessary at each process point will determine water usage. Food allergens often complicate this evaluation, as installations may need to be designed to remove food allergens by using water that otherwise would not be required. the selection of the appropriate hygienic design standards begins with identification of the method of cleaning that will be employed at each process point. it is important that the key stakeholders define the hygienic needs (i.e., type of cleaning) of an installation and forecast the future usage of the manufacturing line and process. new manufacturing line installation is very expensive, and the desire for manufacturing flexibility is very high. The cost of retrofitting a manufacturing line and surrounding infrastructure designed to operate in a dry state to one that accommodates water is much higher than if the process had been designed originally to accommodate water. a multidisciplinary food safety team should determine the current and, to the extent possible, future plans for the manufacturing line and surrounding infrastructure. From these plans, the team should identify the new line’s and infrastructure’s relationship to water. the hygienic design standards will focus primarily on accessibility for dry cleaning and dust control if the equipment and process will remain in a dry state and receive only dry sanitation. Conversely, if the installation requires water, the focus on the installation and infrastructure will require a design that accommodates water, prevents microbial growth niches and receives microbiologically focused sanitation. Common industry practices ❏ building design and layout should be based on hygienic principles, using common practices such as those outlined in the literature (2, 4, 5, 6, 8). ❏ a common approach should be applied to sanitary design that keeps the equipment design as simple as possible and strives for a minimum number of parts, with all parts and assemblies accessible for inspection and cleaning. a program should be established for design review of equipment based on sanitary design principles, including some or all of the principles outlined in table 3 as appropriate. – review new equipment prior to purchase for sanitary design and layout. the proposed layout and placement in the facility should be evaluated to confirm that access necessary for proper cleaning is not compromised. the presence of the new equipment should not compromise the cleanability of existing machinery. – a similar review should be conducted for equipment that is relocated from one facility to another. – plans to modify existing equipment should be reviewed by the plant food safety team prior to beginning the alteration. – existing equipment should be periodically reviewed to verify that it still meets sanitary design principles and has not been altered in a manner that would compromise the sanitary design or cleanability of the equipment. existing equipment should be modified when necessary to eliminate difficult-to-clean areas (such as unsealed hollow components, scratched surfaces, crevices, poor sanitary welds, etc.) and design features that may lead to residue build-up or stagnant products. examples of poor design features are shown in Figures 5 and 6. ❏ if water will be used, the infrastructure and equipment must be designed to accommodate water. development of microbial growth niches must be prevented. Water drainage from the process in the facility must ensure rapid drying. additionally, the infrastructure must be designed to prevent entry of unwanted water from surrounding processes or from outside the facility. ❏ particular attention should be given to sanitary design, layout and maintenance of equipment located in the primary Salmonella Control area (pSCa) to ensure that moisture can be excluded from the processing environment, including the utilization of dry cleaning procedures (see more details in element 4). Conditions leading to the formation of condensate should be eliminated or minimized to the greatest extent possible. JULY 2009 | FOOD PROTECTION TRENDS 441

Food Protection Trends - July 2009

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