Equipment Cleaning and Sanitizing in Food Processing
Objective of Cleaning and Sanitizing Food:
The objective of cleaning and sanitizing food contact surfaces is to remove food (nutrients) that bacteria need to grow, and to kill those bacteria that are present. It is important that the clean, sanitized equipment and surfaces drain dry and are stored dry so as to prevent bacteria growth.
Necessary equipment (brushes, etc.) must also be clean and stored in a clean, sanitary manner.
Cleaning/sanitizing procedures must be evaluated for adequacy through evaluation and inspection procedures. Adherence to prescribed written procedures (inspection, swab testing, direct observation of personnel) should be continuously monitored, and records maintained to evaluate long-term compliance.
The correct order of events for cleaning/sanitizing of food product contact surfaces is as follows:
1.Rinse
2.Clean
3.Rinse
4.Sanitize
Definitions:
Cleaning
Cleaning is the complete removal of food soil using appropriate detergent chemicals under recommended conditions. It is important that personnel involved have a working understanding of the nature of the different types of food soil and the chemistry of its removal.
Cleaning Methods:
There are a number of methods which can be used to apply detergents and disinfectants.
Manual Cleaning
Manual cleaning using cloths, mops, brushes, pads, etc. It is normally used in small areas, equipment that is non-water proof or requires dismantling or areas which are difficult to clean by other methods. It is a labor intensive method and may limit the use of certain chemicals for safety reasons. To ensure cleaning is effective the method must be clearly defined and staff trained to an appropriate level.
Foam Cleaning
This is the common method for cleaning most food operations. A foam blanket, created using a wide range of available equipment is projected from a nozzle and allowed time to act on the soil. It is then rinsed off with the released deposits. Large areas such as floors, walls, conveyors, tables and well-designed production equipment are ideal for foam cleaning.
Foam is a carrier for the detergent. The foam should be applied in an even layer. Coverage rates are quick and chemical usage is economical. Your chemical supplier will advise on the most appropriate chemicals and equipment for your operation. The equipment itself may be mobile, centralised or satellite.
Spray
Spray cleaning uses a lance on a pressure washer with chemical induction by venturi. This method can be wasteful of chemical and can be slow to produce a foam. It should be used where foaming properties are not essential for the cleaning action.
Fogging
Aerial fogging uses compressed air or other equipment to generate a fine mist of disinfectant solution which hangs in the air long enough to disinfect airborne organisms. It will also settle on surfaces to produce a bactericidal effect. The system can come in a small portable device or built in automatic central systems. Fogging should never be used as a primary sanitising method. It should be used in conjunction with other methods. It is also important to ensure that coverage and saturation is sufficient and the mist is fine to allow proper action.
Machine Washing
This is normally an automatic or semi-automatic washing process conducted within a purpose built machine. There are many machine designs depending on the application, e.g. crate washing or utensil washing. They represent a significant capital investment and need to have a clear business case before purchasing. They tend to consume a large amount of chemicals and water. Failure to maintain them correctly can lead to a contamination risk to the product. Chemicals used in these machines should be low foaming. An effective system for controlling the dose of chemical should be employed and temperature control systems should be used where critical.
Sanitization:
It is important to differentiate and define certain terminology:
- Sterilize refers to the statistical destruction and removal of all living organisms.
- Disinfect refers to inanimate objects and the destruction of all vegetative cells (not spores).
- Sanitize refers to the reduction of microorganisms to levels considered safe from a public health viewpoint.
Appropriate and approved sanitization procedures are processes, and thus, the duration or time as well as the chemical conditions must be described. The official definition (Association of Official Analytical Chemists) of sanitizing for food product contact surfaces is a process which reduces the contamination level by 99.999% (5 logs) in 30 sec.
The official definition for non-product contact surfaces requires a contamination reduction of 99.9% (3 logs). The standard test organisms used are Staphylococcus aureus and Escherichia coli.
There are five basic steps in wet cleaning and sanitizing that hold true for almost all types of soil and food processing systems. They are:
- Flush or sweep the excess soil from the surface with water of an appropriate temperature. When sweeping gross soil from floors, squeegees are the preferred tool since they are easier to clean themselves. Brooms, mops or brushes are not recommended in wet cleaning operations. Bogart emphasizes that gross soil removal by flushing is perhaps the most important step, as cleaning compounds are simply not designed to remove it. In addition, using such materials before flushing the surface wastes money.
- Use the appropriate cleaner and method for the surface. Scrubbing to remove stubborn soils also may be necessary.
- Flush the cleaner from the surface with water at an appropriate temperature.
- Apply the appropriate sanitizer.
- Rinse the sanitizer from the surface with clean water, if not using no-rinse sanitizers.
Many also utilize a seven-step sanitation program that incorporates inspection steps.
Now let’s look at sanitizers, assuming that surfaces have been cleaned properly.
When most people think of sanitizers, they think only of chemicals. But one of the best sanitizers is heat, especially hot water or steam. Heating and holding surfaces to 180˚F or above for five minutes using wet heat will effectively sanitize that surface. When using steam in enclosed systems, the recommendation is 200˚F, assuming the outlet temperature for the steam is at that temperature.
There are a wide range of sanitizers available on the market. The one used depends on products, objectives and cost. When selecting a sanitizer, consider factors including:
- Temperature
- Soil load
- pH
- Water hardness
- Type of surface
- Foam level
- Residual activity
In many food plant operations, the sanitation crew will wrap cleaning by applying a no-rinse sanitizer. This provides residual disinfecting activity and will remain on the surface until production is initiated.
Hygiene Monitoring System:
Maintenance of sanitation programs is essential for ensuring safe and quality foods. This means that processors follow to the letter the cleaning programs day after day. And the proof is in the documentation.
The first would be the cleaning record done right after the work was completed. Each and every piece of equipment should be listed for inspection, with a notation that it was cleaned properly. Persons doing these inspections and the pre-operational inspections should be trained on what to look for and should have flashlights to better observe if cleaning was done properly. This document should also include spaces to record cleaner and sanitizer strengths and temperatures employed.
Many companies incorporate a hygiene monitoring program into their clean-up program.
The key words for a good sanitation program are develop, document, implement and maintain. Implementation must include training that is documented, and maintenance must include good recordkeeping and verification programs that ensure the program stays on track and people continue to do what is defined in the documentation.
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