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Proper cleaning and sanitizing is essential to producing high quality, safe dairy products. A well-informed and trained staff provides the foundation for safe food processing. The key concepts of sanitation controls are knowing what to clean, what soils are present, best practices for cleaning steps and washing factors, and understanding how to handle cleaning chemicals safely. Cleaning versus SanitizingThe first step in Sanitation Control is to understand the difference between cleaning and sanitizing.
An area must be cleaned before it can be sanitized. You can't sanitize dirt! What to CleanThe first thing that comes to mind in cleaning is food contact surfaces. But cleaning the outside of equipment, the environment, and personnel hygiene are also necessary to maintain a sanitary environment for food processing. Personnel hygiene (handwashing, uniforms) should be addressed with the Good Manufacturing Practices (GMPs) for your facility, and will not be covered in this article. ExamplesThese are examples of places to clean in a dairy and food processing plant:
The type of food contact surface is an important consideration when determining what types of cleaners and practices to use. The best materials for food processing are durable, non-porous, food-grade, and easily cleanable. Materials that pit, rust or have rough surfaces have microscopic-size valleys that are highly desirable spaces for unwanted bacteria to grow and form hard-to-clean biofilms. Typical materials found in food processing plants include stainless steel, plastic, and tile. Some dairy plants package milk in glass bottles. Some cheesemakers use wood boards for aging and cleaning procedures should be in place to ensure the boards are sanitary. Equipment design and plant layout should be considered from a cleanability perspective. You need to be able to reach around and under equipment to clean it properly. Types of Soils in Dairy PlantsMilk contains 5 types of soils. CarbohydratesMilk carbohydrates are primarily lactose with minor amounts of other sugars. Sugars typically dissolve in water and can be removed with warm water. ProteinsMilk proteins consist of the caseins and serum (whey) proteins. They may or may not be soluble in water. Typically proteins are removed from surfaces using chlorinated alkaline cleaners (high pH); sometimes enzymes and oxidizers are added to help remove proteins. When protein residues build up they leave a bluish or rainbow haze on equipment surfaces. FatMilk fat consists of many fatty acids arranged in triglyceride structures that give it a broad melting range. Milk fat is not fully melted until 104°F (40°C). Alkaline cleaners (high pH) are needed to saponify the fat and remove it from surfaces. It is critical that the wash water be at least 120°F at the end of the wash cycle to ensure that the milk fat is removed completely from all the surface and pipelines in the processing system. If the water is too cold, then the fat will smear rather than being removed. This can result in a layer of sticky fat inside the system that serves as an anchor point for bacteria to form biofilms. MineralsMilk minerals consist of calcium, phosphorus, magnesium, with trace amounts of other minerals. Minerals are removed using acid cleaners (low pH). Milk stone is a whitish or yellowish build up of mineral residue on surfaces. Water conditioning may be used to help prevent regular deposition of water and milk minerals on processing and environmental surfaces. MicroorganismsMicroorganisms in a dairy plant can originate in milk, water, air, be tracked in on boxes, pallets, shoes, personnel, and other vectors. Microorganisms can be washed away from surfaces during routine cleaning, but since they are always present in the environment, food contact surfaces should be sanitized prior to use. The main reason to sanitize equipment is to reduce the microbial load on surfaces prior to use. Biofilms form when bacteria get lodged in crevices and can not be washed away. The bacteria attach to the surfaces, multiply and form large masses that become encased in soils which protect them from cleaning and sanitizing chemicals. These communities contaminate product that moves across the equipment surfaces, and pieces can break off during processing, causing sporadic high micro counts in products. How to CleanThe specific steps used to clean and sanitize equipment and environmental areas are unique to each processor. Sanitation Standard Operating Procedures (SSOPs) are written, step-by-step instructions on cleaning equipment, processing lines, environmental areas, and master sanitation schedules. See the article on Sanitation Standard Operating Procedures for guidelines and tips for writing SSOPs. Equipment and environmental areas may be cleaned using clean-in-place (CIP) systems, clean-out-of-place wash tanks (COP), and manual techniques. When using COP tanks, make sure all parts are completely submerged to ensure adequate cleaning. Hoses and pipes that stick out of the tank will not get washed thoroughly. Follow the manufacturer's instructions and chemical supplier's suggestions when using CIP and COP systems. A good reference for dairy equipment cleaning procedures is Guideline 29 Cleaning and Sanitizing in Fluid Milk Processing Plants, published by The Dairy Practices Council. Many dairy plants use a color-coded brush system to prevent contamination from raw to pasteurized products, and from non-food contact and environmental surfaces to food contact surfaces. It is highly recommended that a separate (black) brush be used ONLY for cleaning drains. Long plastic handles with "drains only" printed on them can be purchased from brush suppliers. When using buckets for sanitizing, make sure the buckets are thoroughly clean before mixing the sanitizer. If the sanitizer appears cloudy, it is no longer effective and should be replaced. Cleaning Chemical SelectionThe selection of cleaning and sanitizing chemicals for use in your facility will depend on:
Often different areas or environments in the plant will require different types of cleaners. For example, a clean-in-place system will use cleaners that don't foam as much as manual cleaners. The sanitizer used in footbaths may be different than the one used of food contact surfaces. There are many types of cleaning and sanitizing chemicals available. Be sure to follow the directions for that particular cleaner or sanitizer - they all have their own optimal concentrations. Be aware of the use requirements and limitations of your sanitizer - many sanitizers are "no-rinse" and should not be rinsed between application and food processing. Sanitizers usually have a period of effectiveness that only lasts for several hours, so if you sanitize your equipment after cleaning the night before, you may need to sanitize again just prior to processing. The best approach is to assess your facility, have your water tested, and work directly with then a chemical supplier to set up a cleaning and sanitizing system that fits the needs of your facility and company philosophy. Cleaning Steps and Washing FactorsThe key concepts of cleaning and sanitizing are summarized in 4 steps: Pre-rinse
Wash
Washing Factors (TACT)
Post-rinse
Sanitize
Chemical SafetyChemicals are used in dairy processing plants and QA laboratories. OSHA regulations state that it is the employer's responsibility to provide adequate training and access to information to ensure that employees work in a safe environment and minimize accidents. Use demonstrations freely when conducting chemical safety training to educate employees on how to properly mix chemical solutions, label chemical containers, wear the correct personal protective equipment (PPE) for the task at hand, and clean up spills. Make sure to document the training session (date of the session, topics covered, employees present) and place it in the training section of your Food Safety Plan. People that work with cleaning and laboratory chemicals should know: Correct chemical use
Chemical properties
Personal Protective Equipment (PPE)
Examples
Accident and Spill Response
The DetailsThe Details summarize the best practices for effective cleaning and sanitizing in dairy and food plants. Follow SSOPs
Use the Right Supplies
Fill Out Records
Take Pride
Printing the ArticleThis article is formatted for printing the text of the poster. The 2-page poster and four (4) flashcards are available as free downloads (pdfs). The poster and flashcards are visual reminders of key concepts in cleaning and sanitizing dairy and food processing plants. They can be displayed on doors, lockers, processing areas, CIP rooms, chemical storage areas, lunchrooms, and employee notice boards. The flashcards can be posted with the key concept side visual as a quick reminder or posted with the details visible for more information. The flashcards can be used as quiz aids for on-site training. The poster and flashcards can be purchased on water-resistant paper suitable for display in a dairy plant environment. Learn more about sanitation and best practices to ensure food safety through our new online course Food Safety and Sanitation for Food Manufacturers |