Food Protection Trends - July 2009 - 442

TABLE 5. - Examples of common industry procedures for controlled wet cleaning remove as much residue as possible by dry cleaning. avoid overuse or careless use of water. procedures for collecting water should be in place to prevent water spreading on the floor or following product conveyance lines or other connections to non-wet cleaned areas of the facility. Commercial pre-moistened sanitizing wipes may be used to spot-clean specialized areas with minimal introduction of water. never use high pressure water application, even for situations such as to get rid of dry build-ups, as the over-spray will spread to other areas and contaminants can be aerosolized. When drains are not used for wet cleaning they must be sealed. during cleaning, there should be no changes in procedures for entering the primary Salmonella Control area — all barriers still apply, e.g., entering through the buffer area and following required procedures. always apply a sanitizing step following the controlled wet cleaning. Ensure prompt and complete drying of all areas and components involved (equipment, parts, floors, the environment, etc.) after controlled wet cleaning. all equipment parts and environmental sites must be visually inspected for any remaining wet spots before the sites are released for production. Consideration should be given to evaluating the microbiological quality of the first product through the equipment to verify the efficacy of the controlled wet cleaning process. - ❏ hygienic design standards and strict adherence to sanitation performance specifications must be applied to construction and major maintenance activities. these activities can dislodge microbial growth niches and lead to widespread contamination of the facility. the plant food safety team should evaluate this work and conduct an evaluation of the risk of introducing physical, biological or chemical hazards into the facility. based on this evaluation they should define and implement the appropriate preventive measures, such as temporary isolation of the construction or maintenance sites, rerouting of employee and equipment traffic, proper handling of waste material egress, maintaining negative pressure in the work site, etc. ❏ equipment maintenance should follow hygienic procedures such as those described in element 1 (12) and element 2 as appropriate. unscheduled maintenance is particularly risky, and hygienic procedures should be strictly followed. ❏ a wide range of accessory tools such as supports and ladders may be located inside large equipment or inside the pSCa. hygienic design is critical and these tools/structures should not have features such as hollow bodies, loose parts or uncleanable surfaces. ❏ elevated infrastructure should be designed to minimize dust and dry material accumulation, especially when pipes, overhead structures and platforms are directly above exposed products or production lines. SALMONELLA ConTRoL ELEMEnT 4: PREVEnT oR MInIMIZE GRoWTH oF SALMONELLA WITHIn THE FACILITY moisture control is critically important in preventing Salmonella contamination in low-moisture products (11). Water in the dry processing environment is one of the most significant risk factors (perhaps the single most important factor) for Salmonella contamination, as water allows for pathogen growth, significantly increasing the risk for product contamination. industry experience indicates that the presence of water, even in very small amounts present for short, sporadic time periods, may allow Salmonella to grow in the environment. at times, moisture is obvious in the form of water droplets or puddles; at other times, it may be from sporadic sources such as roof leaks. however, many sources of moisture, such as high relative humidity or moisture accumulating inside of equipment, are not visually apparent. Salmonella can, to varying degrees, be introduced into low-moisture product manufacturing facilities and become established in those environments. harborage sites may develop and become a source of product contamination unless these sites are identified and eliminated (2). a harborage site, or niche, is a site in the environment or on equipment (junctions, cracks, holes, dead-end areas, etc.) that enables the accumulation of residues (food debris, dust, and water) and permits the growth of microorganisms such as Salmonella. These sites may be difficult to inspect or access and therefore can protect Salmonella during routine cleaning and sanitizing. growth of Salmonella is possible only in the presence of water. Since food par- ticles and dust are normally expected to be present in processing areas, adequate nutrients are always available to microorganisms. growth cannot occur, however, if the plant environment is sufficiently dry. the potential Salmonella harborage sites become more significant when water is present for a sufficient period of time. the presence of water in the dry processing environment can result from improper use of water during cleaning, which has been linked to the occurrence and spread of Salmonella (2). other events resulting in the presence of water in a dry area include condensate formation, leaking water or steam valves, infiltration of water following heavy rains (e.g., leaky roofs), the use of water showers in the case of fire emergencies, etc. (2). efforts must be made to remove water immediately from the pSCa in such events in order to keep the plant environment as dry as possible. dry conditions must be maintained at all time in the pSCa, except for the occasions when controlled wet cleaning is deemed essential. potential problems arise when there is visible water present in the dry areas or when there are areas in which standing water has dried. Salmonella may be found not only in wet spots but also in spots where standing water has dried (14). the latter situation may present an additional risk of spread via the generation of airborne contaminated dust. dry cleaning is typically employed when conducting sanitation in the pSCa. the objective is to eliminate water from the area so that, despite the presence of food and other substrates, microorganisms (including Salmonella) will not grow. Without growth, Salmonella, if present, remains at very low levels, thus reducing the risk of product contamination. dry cleaning has been successfully applied for many years in production of low-moisture 442 FOOD PROTECTION TRENDS | JULY 2009

Food Protection Trends - July 2009

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