Proper Cleaning and Sanitizing

To produce high-quality, healthy dairy foods, proper cleaning and sanitising is necessary. Unlike the usual house cleaning, professional knowledge is required to provides the basis for healthy processing of foods.

Knowing what to clean, what contaminants are present, best practises for cleaning measures and washing variables, and understanding how to safely handle cleaning chemicals are key concepts in sanitation management.

Cleaning versus Sanitizing

  • Cleaning removes soils from surfaces
  • Sanitizing reduces the microorganism 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 when cleaning is surfaces that are contact with food. But to maintain a sanitary atmosphere for food processing it is also important to clean the outside of the equipment, the atmosphere and staff hygiene. Personal hygiene (hand washing, uniforms) should be discussed for your facility using Good Manufacturing Practices (GMPs), which will not be mentioned in this report.


There are examples of cleaning areas at 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 amount of surfaces contact with food is an important factor when deciding what cleaners and procedures to use. Best food processing materials are durable, non-porous, food-grade, and simple to clean. Materials that pit, rust or have rough surfaces have microscopic valleys which are highly attractive spaces to expand and form hard-to-clean biofilms for unwanted bacteria.

In food processing plants traditional materials include stainless steel, plastic and tile. Some dairy plants use glass bottles to package milk. To ensure the boards are sanitary, some cheese makers use wood boards for ageing and cleaning procedures should be in place.

The design and layout of the equipment and the plant should be viewed from the perspective of cleanability. To clean it properly you must be able to reach around and under the equipment.

Types of Soild in Dairy Plants

Milk contains 5 types of soils.


Milk carbohydrates are predominantly lactose with small amounts of additional sugars. Usually, sugars dissolve in water, and can be dissolved with hot water.


Milk proteins are the caseins and the components of the serum (Whey). They can be soluble in water or not. Using chlorinated alkaline cleaners (high PH) are usually extracted from the surfaces. Enzymes and oxidizers are often applied to further eliminate proteins. They leave a bluish or rainbow haze on the surfaces of equipment as protein residues build up.


Milk fat is made up of many fatty acids arranged in triglyceride structures which give it a wide range of melts. Milk fat is not completely melted. Alkaline (high PH) cleaners are needed to saponify the fat and extract it from surfaces. It is important that at the end of the wash cycle the wash water should be at least 120 Fahrenheit to ensure that the milk fat is completely extracted from all the surface and pipelines in the processing system. If the water is too cold do instead of being absorbed the fat can smear. This can result in a layer of sticky fat inside the system which serves as an anchor point for biofilm-forming bacteria.


Milk minerals, with trace quantities of other minerals, consist of calcium, posphorus, magnesium. Minerals are extracted by means of acid purifies (low PH). Milk stone is a whitish or yellowish mineral powder build up on the surfaces. Water conditioning can be used to help prevent water and milk minerals from constantly depositing on manufacturing and environment surfaces.


In a dairy farm, microorganism can occur in milk, water, air, can be tracked in on bottles, pallets, shoes, staff and other vectors. During regular washing, microorganisms can be washed away from surfaces, bu because they are still present in the atmosphere, surfaces on contact with food should be sanitised before usage. The key reason why the equipment is sanitised is to reduce the microbial load on surfaces before use.

When bacteria get stuck in crevices, biofilms form and can not be washed away. The bacteria bind to the surfaces, multiply and form large masses that are embedded in soils that shield them from chemical cleaning and sanitization. These communities are contaminating the product that passes through the surfaces of the equipment, and pieces may break off during processing, causing high intermittent micro counts in products.

How to Clean

Each processor has unique specific steps to clean and sanitise equipment and environmental areas. Standard operating procedures for sanitation (SSOPs) are written step-by-step guidance on cleaning equipment, production lines, environmental areas and master hygiene schedules. For instructions and tips for writing SSOPs see the article in Sanitation Standard Operating Procedures.

Clean-on-place (CIP) systems, clean-out-place wash tanks (COPs), and manual techniques can be used to clean equipment and environmental areas. Make sure all sections are fully submerged by using COP tanks to ensure proper cleaning. Hoses and pipes which stick out of the tank won’t be thoroughly washed. Follow guidance from manufacturers, and recommendations from chemical suppliers when using CIP and COP devices. Guideline 29 Washing and Sanitizing in Fluid Milk Processing Plants, provided by The Dairy Practices Council, is a clear guide for dairy equipment cleaning procedures.

A colour-coded brush system is used by many dairy plants to avoid contamination from raw to pasteurised products, and from non-food touch and environmental surfaces to surfaces in food contact. A separate (black) brush is strongly recommended only for cleaning drains. Long plastic handles can be bought from brush manufactures, with “drains only” written on them.

Until adding the sanitizer, ensure the bucket are properly washed while using buckets for sanitising. If the sanitizer has a blurry look, it is no longer successful and should be replaced.

Cleaning Chemical Selection

The choice of chemicls to be used in your facility for cleaning and sanitsing will depend on :

  • Soil type
  • Surface type
  • Application method (clean out of place)
  • Environment
  • Water quality

Various areas or situations inside the plant may also need various types of cleaners. A clean-in-place system, for example, would use cleaners that don’t foam as much as hand cleaners. The sanitizer used in football baths could be different from the one used for surfaces with food contact.

There are several types of chemicals used to clean and to sanitise. Be sure to obey the instructions for the particular cleaner or sanitizer-they all have optimum concentrations of their own. Be mindful of your sanitizer’s use criteria and restrictions-many sanitizers are “no-rinse” and should not be rinsed during application and food processing. Sanitizers typically have a time of usefulness that only lasts for several hours, so if after cleaning the night before you sanitise your equipment, you may need to sanitise it again right before the loading.

The best approach is to analyse your facility, test your water and work directly with a chemical supplier to develop a cleaning and sanitsing system that suits the needs of your facility and philosophy of the business.

Cleaning Steps and Washing Factors

The central cleaning and sanitising principles are outlined in 4 steps :


  • Removes loose soil surfaces pior to cleaning
  • Use warm water (100-120 Fahrenheit)


  • Removes carbohydrate, fat, protein and minerals soils
  • Follow SSOPs for cleaning procedures and chemical selection


  • 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)
  • Loosen soils and disrupts biofilms
  • Need to have contact with all surfaces
  • Use turbulent flow, slugging
  • Chemical Concentration
  • Too little: not enough cleaning powder
  • Too much: may reduce efficiency, may leave residues, wastes money
  • Just right: does the job
  • Temperature
  • Use the correct temperature according to the SSOPs
  • 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 microorganism on surfaces
  • Sanitize surfaces before use
  • Only clean surfaces can be sanitized

Chemical Safety

Chemicals are used in dairy processing facilities and QA labs. OSHA regulations note that it is the duty of the employer to have sufficient instruction and access to information to ensure workers are operating in a healthy atmosphere and to prevent injuries.

Use free presentations to teach staff how to correctly mix chemical products, label containers, wear the correct personal protective equipment (PPE) for the job at hand clean up spills while doing chemical safety training. Make sure the training session is recroded (date of the workshop, topics discussed, employees present) and included in your Food safety Plan training section.

People who deal with chemicals for cleaning and laboratory use 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 hazard (flammable, explosive, reactive)
  • Heath hazards (burns, poisons, carcinogens)

Personal Protectice Equipment (PPE)

  • Gloves, lab coats, coverall 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 summarise best practises in dairy and food plants for the effective cleaning and sanitsing.

Follow SSOPs

  • develop Standard Sanitation Operating Procedures (SSOPs) spefically for equipment and environmental areas to meet the needs of you 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
  • colour-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

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