Food Protection Trends - July 2008 - 477

the water supply, the quality of the water supply contributes to the overall cleanliness of the plant. The PMO states that dairy plant water supplies must be of a “… safe, sanitary quality” and should be tested by a certified laboratory at least every 6 months. In-plant testing of water quality is advisable for immediate detection of potential problems. An example of an in-plant testing protocol to monthly tests of water from several sources, such as sinks and hose stations. Collected in-plant water samples are then plated on aerobic count plates (2). Potential coliforms in the water supply are best tested by a presence/ absence method such as Colilert, which, like use of petrifilm, is relatively cost effective and requires little operator training (5). A number of cheese types, such as Gouda and Morbier, include a curd washing step in which water is added directly to the curd/whey mixture. To avoid the risk of contamination from the water source, some cheese makers have chosen to add only filtered or UV-treated water. Water sources for humidity control in ripening rooms must also be controlled. All water sources must be equipped with backflow prevention devices. Microbial air quality within the plant should be monitored. A simple technique for monitoring air quality is the 3M air sampling technique, using 3M plates (3). For farmstead operations or plants located in urban areas, it is advisable to filter plant-intake air. All incoming air should be filtered through a sterilizing filter and the plant should be under positive air pressure to prevent the entrance of bacteria through cracks or open doors. As a general rule, plant air should be filtered 16 times per hour, and care should be taken that filters are dry because wet filters lead to mold and bacteria growth. Filter efficiency can be improved by bringing the filtered air past a metal-based filter or a UV light source. A UV activated titanium dioxide catalyst removes odors and unwanted bacteria. Personal hygiene. Plant employees can spread pathogens around the plant and thus potentially can contaminate in-process or finished food products. Listeria has been isolated from the hands and clothing of food workers (29). A rigorous and thorough hand washing protocol is one of the most effective strategies for LM control. For plant GMPs and pathogens control, each strategically placed hand washing station must: (1) be kept clean; (2) be continuously supplied with a biocidal-detergent; (3) contain hand rinsing capability; and (4) be supplied with paper towels for hands drying (44). Mandated hand washing prompt signs and documented personal hygiene procedures need to be appropriately posted at each hand wash station and in rest room(s). A designated changing area also serves as a storage area for personal clothing and footwear. Upon entering production areas, all workers (as well as visitors) should step through either a sanitizer foot bath or a sanitizer foam sprayer (activated by either a timer or a motion detector). Footwear sanitation devices are quite effective in eliminating and/or controling LM contamination on personnel footwear (49) as long as the sanitizer is regularly changed (often 2–3 times/8 h) and the sanitizer concentration is maintained. Quats (~ 800 ppm) are commonly used in foot baths because of their residual effect, as compared to chlorine-based solutions. However, because of their residual effect, quats may interfere with the fermentation. Other options are iodophors (iodine complex in phosphoric acid) or peroxy acetic acid. Many dairy plants utilize a foot bath containing 25–35 ppm iodophor, since with loss of solution strength it loses its readily recognized amber color intensity. Hair and beard nets must always be worn and should always be available at the entrance to production area(s). It is most important that personnel recognize and appreciate that LM can presumably be found in all areas of the plant environment (i.e., in soils, water, air, aerosols, floors and floor drains, on insects and animals, in raw milk, and on footwear, clothing, and skin). Hazard Analysis Critical Control Points (HACCP). Before starting up cheese production, it is important to consider risks involved in each step of the process and to develop strategies for controlling these risks, i.e., to develop a HACCP plan. This involves preparing a detailed process flow chart that diagrams each step or unit operation and that lists the inputs (raw materials and ingredients) and outputs (finished product[s] and whey), and the potential sites for contamination occurrence (human or product contact surfaces) as well as potential microbial kill (i.e., pasteurization) assessment (45). This science-based undertaking of a formalized risk analysis (which is globally recognized and accepted) then reveals which steps of the process should be constantly monitored and controlled, thus providing for a determination of when “process is out of control” and corrective action protocols are mandated. A HACCP plan, in concert with its Prerequisite Programs, functions to provide the ultimate in food safety for food processing plants. A list of (not all inclusive) some examples (but not all inclusive) of HACCP Prerequisite Programs are: Sanitation, Facilities & Equipment Preventive Maintenance, GMP’s, Pest Control, Personal Hygiene, Training, Internal Audits, Specifications and/or COA’s (Certificates of Analysis for raw materials, ingredients and packaging materials), Allergenic/Sensitizing Agents Control, Emergency Response/recall Plan, and Food Plant Site Security. Developing and implementing a formal HACCP Program may seem overwhelming for an artisan cheese processor. However, assistance is available either through the internet (52) or in reference books (21). HACCP plans are both plantand product-specific, but pre-developed plans can provide the framework on which to build a HACCP plan specifically adapted to the production of cheeses at an individual facility. When developing a HACCP plan for raw milk cheese production, there is no apparent kill step to control LM. Instead, alternative options can be utilized, most notably the testing of incoming raw milk and control of the rates and extent of the fermentation process (14). Many foodborne outbreaks are linked to products that were produced in manufacturing situations that deviated from normal procedures. For example, the electric service was lost, the boiler failed, starter cultures lost their activity, etc. Therefore, it is essential to observe and fully document the process of every single lot of finished product in terms of: (1) a record of any unusual occurrences; (2) code numbers of each lot(s) of raw materials; (3) ingredients; and (4) directcontact packaging materials. Time, temperatures, pH values and other essential process parameters must be recorded, and the records must be retained for at least 2 years (a general food industry rule of thumb is “the shelf-life period, plus one year”). Hence, the manufacturing records for a given lot of 4-year-old “aged cheddar” would need to be retained for a period of at least 5–6 years (4 yrs aging + 9 months sell-by-date on the package + the one-year-expectation). JULY 2008 | FOOD PROTECTION TRENDS 477

Food Protection Trends - July 2008

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