Sanitation for Dairy Plants

Sanitation Controls are an element of Food Safety Plans that are required for all food processors by the Food Safety Modernization Act. The end result is high quality, safe dairy products.
Sanitation for Dairy Plants - Articles

Updated: October 15, 2017

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Sanitation for Dairy Plants

Sanitation starts in the milking parlor and continues through delivery of your products to the customer. Sanitation Controls outline procedures and programs used to maintain a sanitary condition for food processing.

Sanitation Controls are an element of Food Safety Plans that are required for all food processors by the Food Safety Modernization Act, and can encompass:

  • personnel hygiene
  • handling of ingredients, packaging material, and finished products
  • processing and packaging equipment
  • fermentation and aging rooms
  • storage areas
  • the whole facility environment

Cleaning and sanitizing procedures can be incorporated into your processing routine as part of:

  • good manufacturing practices (GMPs)
  • prerequisite programs (PPs)
  • sanitation standard operating procedures (SSOPs)
  • a master sanitation plan for tasks done daily, weekly, monthly, semi-annually, or periodically as indicated

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 Sanitizing

The first step in Sanitation Control is to understand the difference between cleaning and sanitizing.

  • Cleaning removes soils from surfaces
  • Sanitizing reduces the microorganisms on surfaces

An area must be cleaned before it can be sanitized. You can't sanitize dirt!

What to Clean

The 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 (hand washing, uniforms) should be addressed with the Good Manufacturing Practices (GMPs) for your facility, and will not be covered in this article.


These are examples of places to clean in a dairy and food processing plant:

  • Food contact surfaces
    • equipment surfaces
    • tables and preparation areas
    • conveyors
    • utensils
    • bins and totes
    • packaging materials
  • Outside of equipment
  • Environment
    • floors
    • drains
    • walls
    • light fixtures

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 cheese makers 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 Plants

Milk contains 5 types of soils.


Milk carbohydrates are primarily lactose with minor amounts of other sugars. Sugars typically dissolve in water and can be removed with warm water.


Milk 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.


Milk 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.


Milk minerals consist of calcium, phosphorous, 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.


Microorganisms 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 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 Clean

The 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 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 manufacturers instructions and chemical suppliers 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 Selection

The selection of cleaning and sanitizing chemicals for use in your facility will depend on:

  • soil type
  • surface type
  • application method (clean-in-place, clean-out-of-place, manual
  • environment
  • water quality

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 Factors

The key concepts of cleaning and sanitizing are summarized in 4 steps:


  • removes loose soil from surfaces prior to cleaning
  • use warm water (100-120°F)


  • removes carbohydrate, fat, protein and mineral soils
  • follow SSOPs for cleaning procedures and chemical selection
Washing Factors (TACT)
  • Time
    • too little: not enough surface interaction
    • too much: temperature cools, detergent deposits
    • just right: surface wets, soils are removed and washed away
  • Action (Mechanical Force)
    • loosens soils and disrupts biofilms
    • need to have contact with all surfaces
    • use turbulent flow, slugging
  • Chemical Concentration
    • too little: not enough cleaning power
    • too much: may reduce efficiency, may leave residues, wastes money
    • just right: does the job
  • Temperature
    • use the correct temperature according to the SSOPs
    • water should be 120°F at the end of the wash cycle
    • too hot: proteins denature and deposit, dangerous for personnel


  • removes detergent and chlorine
  • rinse water may be acidified (Acid Rinse)
  • removes minerals and prevents mineral deposits


  • reduces the number of microorganisms on surfaces
  • sanitizes surfaces before use
  • only clean surfaces can be sanitized!

Chemical Safety

Chemicals 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 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

  • the right chemical and concentration needed for the job
  • the correct mixing and use procedures
  • how to label and store chemicals properly

Chemical properties

  • the physical state (solid, liquid, gas), concentration, and pH of the chemicals
  • physical hazards (flammable, explosive, reactive)
  • heath hazards (burns, poisons, carcinogens)

Personal Protective Equipment (PPE)

  • gloves, lab coats, coveralls and footwear
  • eye, face, and head protection required
  • use the correct materials for the task


  • use chemical rated gloves, not latex gloves for handling cleaning chemicals
  • wear a full face mask when handling caustic and acidic cleaning chemicals

Accident and Spill Response

  • the use and location of emergency equipment
  • emergency first aid procedures
  • have emergency contact numbers easily accessible
  • have spill kits accessible and use procedures in place

The Details

The Details summarize the best practices for effective cleaning and sanitizing in dairy and food plants.

Follow SSOPs

  • develop Standard Sanitation Operating Procedures (SSOPs) specifically for equipment and environmental areas to meet the needs of your facility
  • include step-by-step directions on how to clean, and how often to clean
  • specify the correct chemicals, times, temperatures and processes to use

Use the Right Supplies

  • correct chemicals and concentrations
  • appropriate Personal Protection Equipment (PPE) for chemical handling
  • color-coded brushes and buckets, the correct wash tanks, etc.

Fill Out Records

  • sanitation records and logs
  • Food Safety Plan monitoring and verification records
  • if it wasn't documented, it wasn't done!

Take Pride

  • smile and take pride in producing clean, safe food!

Printing the Article

This article is formatted for printing as a summary poster and as flashcards with the key concepts on the front and full details on the back.

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, lunch rooms, 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 a quiz aids for on-site training.

The poster and flashcardsare available as a free download or can be purchased on water resistant paper suitable for display in a dairy plant environment.

Consistently using correct cleaning and sanitizing procedures in dairy and food processing plants is the foundation to producing high quality, safe food. Sanitation Standard Operating Procedures (SSOPs) are detailed procedures specifying what to clean, how to clean, how often to clean, and the records used for monitoring.

What is a Sanitation Standard Operating Procedure (SSOP)?

A Sanitation Standard Operating Procedure (SSOP) is a written document of procedures or programs used to maintain equipment and the environment in a sanitary condition for food processing. It is a step-by-step description of cleaning and sanitizing procedures and specifies

  • what is to be cleaned
  • how it is to be cleaned,
  • how often it is to be cleaned, and
  • what records are used to monitor the procedures.

An SSOP is a fundamental part of a Food Safety Plan. It may be a stand-along procedure or may be a Prerequisite Program (PP). It shall be updated whenever there is a change in processes or chemicals used. It should be reviewed annually with the Food Safety Plan. An SSOP may written for

  • a piece of equipment,
  • several pieces of equipment in a process,
  • an environmental area,
  • as a Master Sanitation Plan for the whole facility.

Tips for Writing SSOPs

Use Clear Language

SSOPs should be written in a concise, easy-to-read format. Simple, direct terms are the most effective. Ambiguous directions, or long instructions can be difficult to follow correctly.

If employees are not native English speakers, consider having a alternative version available in their first language. When training non-native English speaking employees, it is critical that they understand the details of the procedures and the proper use of chemicals before beginning their job. This will ensure the utmost sanitary condition for processing, reduce food safety risk, and minimize employee accidents.

Completely Describe the Steps

An SSOP is a step-by-step document.

  • use a numbered sequence for the steps

Describe the steps completely.

  • identify specific cleaning chemicals (type, brand, name, concentration)
  • include the temperature and time conditions needed to achieve proper cleaning

Add notes for clarification as needed.

  • notes are particularly useful when identifying specific hazards, such as making sure the correct personal protection equipment (PPE) is put on prior to handling caustic chemicals.

An SSOP should be considered a training document.

  • when a new or relief employee is asked to do this task, can they follow this SSOP and get the job done correctly and timely?

Identify the Monitoring Records

Monitoring records are an integral part of a Food Safety Plan. Monitoring records are logs, charts, and other documents that prove that cleaning and sanitizing occurred. Monitoring records should be filled in the date and signature or initials of the person completing the task.

If it wasn't documented, it wasn't done!

Examples of monitoring records include

  • chemical concentration logs,
  • cleaning schedule logs,
  • pasteurization chart with the CIP cycle, and
  • periodic checklists on the Master Sanitation Plan.

Elements of an SSOP

Here is a checklist of elements that should be included in an SSOP:

  • Company Name
  • Date (most recent update or effective date)
  • Version ID
  • SSOP Number (optional). Some companies assign numbers to their SSOPs, they may combine the SSOP number and version. Example: SSOP #3, version 5 may be SSOP: 3.05
  • Title (the name of the procedure or program)
  • Scope or Introduction (what is covered)
  • Frequency (how often this should be done)
  • Procedures: Step-by-step instructions. Use a logical, sequential order/ Add notes as needed for clarification. Specify: chemicals (type, brand name), chemical concentration, time, temperature. Break into sections for multiple tasks.
  • Recordkeeping. Identify which forms or logs are used. Example: chemical concentration logs.
  • Person responsible for the SSOP content and updates. Include signature and date lines.
  • Page numbers

Example SSOP

Kay's Kreamery
SSOP: 3.05

State College, PA
Date Updated: April 15, 2015

Cheese Process Equipment Cleaning and Sanitizing


Cheese process equipment includes the pasteurizer, cheese vat, cheese press, tables, and utensils used during the manufacture of cheese.

Cleaning and Sanitizing Schedule

Processing equipment is sanitized immediately prior to use and cleaned at the end of each processing day.

Manual Sanitizing

  1. Fill 5 gallon bucket with room temperature water.
  2. Add 1 packet of ABC powdered sanitizer (HIJ Company) to the bucket. Stir to dissolve.
  3. Sanitize equipment using a clean brush, making sure to sanitize all surfaces and parts.

Manual Cleaning (in a sink)

  1. Dismantle equipment to be cleaned and rinse parts with warm water.
  2. Make cleaning and sanitizing solutions according to manufacturers instructions. Note: wear appropriate personal protection equipment (gloves, eye protection)
  3. Wash parts using a clean brush, making sure to wash all surfaces and parts.
  4. Rinse thoroughly with warm water to remove cleaner residues.
  5. Rinse parts with sanitizer solution.
  6. Visually inspect parts for damage and residual cleaner.

CIP Cleaning of the HTST Pasteurizer

1. Continue the flush rinse after product processing until the clean water comes out of the product lines (at least 20 min). Maintain water level in balance tank.

2. Prepare the HTST and Homogenizer for CIP.

  1. Turn the Temperature Set Point down to allow the flow to divert. Shut off the booster pump, homogenizer, and hot water system. Turn off the chilled water.
  2. Turn the switch on the Back Panel (CIP box) from Product to CIP.
  3. Reconnect the product recirculation line. Remove end caps and reconnect the bypass line on the homogenizer.
  4. Turn the Product Flow to CIP on the Control Panel.

3. Turn HTST system back on and stabilize conditions.

  1. Check water level in balance tank, and add water if needed.
  2. Release the backpressure using the Back Pressure Regulating Valve.
  3. Adjust the Temperature Set Point to 180°F.
  4. Turn on the Homogenizer and Booster Pump to High Speed. Turn on the Hot Water System at the control panel.

4. Add Caustic and circulate for 20 min.

  1. Add city water to the balance tank to a level just below the side port.
  2. Add 4.5 lbs of caustic (EFG caustic cleaner by HIJ Company) to balance tank
  3. Take a sample of the caustic solution from the balance tank and check concentration using the test kit for Caustic Wash. Record concentration of caustic wash on the Sanitation Test Log.
  4. Caustic solution should be 1 - 1.5%; adjust concentration and retest as needed.
  5. Switch between Forward and Diverted Flow a few times to clean the entire system.

5. Drain caustic solution.

  1. Turn Flow Valve to Drain.
  2. When balance tank is almost empty add clean water to balance tank for rinse.

6. Rinse with clean water 20 - 30 min.

7. Add acid and circulate for 20 min.

  1. Turn flow valve back to Forward Flow F/F.
  2. Add city water to the balance tank to a level just below the side port.
  3. Add 1.5 lbs of acid (KLM acid cleaner by HIJ Company) to balance tank.
  4. Take a sample of the acid solution from the balance tank and check concentration using the test kit for Acid Wash. Record concentration of acid wash on the Sanitation Test Log.
  5. Acid solution should be 8,000 - 10,000 ppm; adjust concentration and as needed.
  6. Switch between forward and diverted flow a few times to clean the entire system.

8. Rinse with clean water 30 - 45 min.

  1. Turn flow valve to Drain.
  2. When balance tank is almost empty, add clean water to balance tank for rinse. Add water as needed to complete rinse cycle.
  3. After rinse is complete, drain tank until only a small amount remains in the bottom.

9. Cool System.

  1. Turn off Steam Valve at control panel and allow the temp to drop below 140°F.
  2. Adjust the Temperature Set Point to 120°F.
  3. Wait until the temperature of the system is < 120°F before turning off the system.


  • The results from testing the concentrations of cleaning solutions are recorded on the Sanitation Test Log immediately following the test.
  • CIP cleaning of the pasteurizer is recorded on the Pasteurization Chart at the end of the production run each day.
  • Manual cleaning of the cheese vat, tables and equipment is recorded on the Daily Cleaning Log.

The following individual is responsible for implementation of this SSOP:

Name: Jane Doe
Title: Plant Manager
Date: 4/15/15

Water-resistant Version

For a nominal fee, the set is available on water resistant paper suitable for display in a dairy plant environment.

The traditional practice of using wood boards for cheese aging must meet the contemporary practice of sanitation to ensure food safety.

The use of wood boards for aging is a longstanding tradition in cheese manufacture. The properties of wood that are beneficial for cheese aging can also pose food safety hazards, namely its porosity and tendency to develop biofilms.

The porosity of wood provides a natural wicking effect that helps to dry and age cheese. The wood pores serve as sites for bacteria to congregate, grow and develop biofilms. This can be beneficial when populations of desirable organisms grow and promote the development of positive attributes to the cheese rind and flavor. However, this is also an opportunity and ideal conditions for pathogens to grow. Some research studies have shown that populations of desirable bacteria may out-compete and inhibit the growth of pathogens. But the risk of pathogen survival in the wood is a serious concern and must be addressed by good sanitation practices.

Practices for Using Wood Aging Boards

Good practices for using wood aging boards in cheese manufacture are:

  • use boards that are safe for food contact
    • check to make sure any wood preservative used are food grade
  • use boards that are of sound construction, in good condition, and free from surface defects
  • make sure boards can be easily removed from their support system for cleaning and inspection
  • inspect boards regularly for damage
  • replace boards when they are compromised
  • maintain proper monitoring procedures for environmental bacteria
  • keep corrective action plans updated in case of unwanted contamination

SSOPs for Wood Aging Boards

Facilities that use wood boards for aging cheese should have a Sanitation Standard Operating Procedure (SSOP) in place to ensure that proper cleaning and sanitation procedures are written, followed and documented. Key elements to include in an SSOP for wood boards are:

  • frequency of inspection
  • cleaning and sanitizing procedures
  • frequency of validation that cleaning procedures are adequate
    • example: swab testing of clean board surfaces for presence of bacteria
  • frequency of cleaning
  • identify the records used for monitoring
  • corrective actions in case of contamination

Cleaning and Sanitizing Procedures for Wood Aging Boards

Wood boards should be cleaned and dried in the same building as the aging room to avoid outside contamination. Wood boards should not come in contact with the floor or other unsanitary surfaces at any time.

The minimum, suggested cleaning conditions are:

  1. Wash and scrub boards with 140°F soapy water.
  2. Rinse boards with 140°F water.
  3. Sanitize boards with either a 200 ppm chlorine solution or a 10% hydrogen peroxide solution. Do not rinse off the sanitizing solution.
  4. Dry boards thoroughly using air or in a drying kiln. Air-dried boards should be placed on metal shelves with sufficient space between the boards for proper air flow.
  5. Store clean, dry boards in a sanitary manner until next use.
  6. Fill out cleaning and sanitizing records.


The author thanks Marianne Smukowski from the Wisconsin Center for Dairy Research for her input on cleaning and sanitizing procedures.