Spiral freezer: Cleaning guidelines
To maintain a high level of hygiene and food safety in your food processing plant, it is essential to have complete control of the cleaning process and that all elements come together to get the optimum results. Chemical mix and concentration, water temperature and contact time must be tailored to deal with the type of soil on the equipment and surfaces.
The cleaning steps below apply to an automated cleaning process of a spiral freezer. However, the order of the steps is generally applicable to cleaning in the food and beverage industry, also manual cleaning.
Concentration of chemicals
Ensure that the chemicals used are effective in dealing with the soils and residues they are meant to dissolve. Having the correct chemical mix is a key factor. Consult your chemical supplier if you have doubts or questions.
Make sure that the water temperature combined with the detergent is sufficient to dissolve and remove the residues on the freezer.
Contact time of chemicals
Make sure that the detergents are left on the surfaces for an appropriate number of minutes to take effect and dissolve the residues. Consult your chemical supplier for instructions on this. If the contact time is too short, the detergents will fail to dissolve the residues, and if it is too long, they may dry out making them hard to rinse off.
An automatic cleaning process of a spiral freezer is comprised of segments carefully tailored to match the nature of the freezer and the product in terms of duration and number of segments. The steps below are based on a single-drum freezer with 6 segments: 4 segments covering the belt by vertical nozzle bars and 2 segments placed on top with rotating nozzles. The cleaning process is segmented such as not to transfer residues to already cleaned surfaces.
Before launching the automatic process, excess soil from the freezer should be removed manually.
Initiate the automatic cleaning:
- Step 1: Rinse one segment at a time for the duration specified.
- Step 2: Apply foam product one segment at a time.
- Step 3: Allow contact time (in accordance with chemical supplier’s instructions).
- Step 4: Rinse off foam one segment at a time.
Before moving on to the apply sanitizer/disinfectant, the operator should inspect surfaces to ensure they are visually clean. If possible, use rapid kits (ATP for example).
- Step 5: Sanitize/disinfect all clean surfaces to reduce microorganisms to an acceptable level (bacteriologically clean). Applying sanitizer/disinfectant on an unclean surface render this step ineffective.
- Step 6: Allow contact time (in accordance with chemical supplier’s instructions).
- Step 7: Final rinse.
- Step 8: Allow to air dry.
Standard segmentation of cleaning process
For a single-drum spiral freezer, the standard cleaning process is divided into 6 segments: 4 segments covering the belt by vertical nozzle bars and 2 segments placed on top with rotating nozzles.
The vertical nozzle bars are fixed to cover the entire width of the conveyor belt by spraying from different angles. Rotating nozzles are fixed on top and ensures that the water and detergents applied penetrate the freezer from above and sanitize the belt support rails and related structures.
Spiral freezer specifications
|Conveyor belt, width||800 mm|
|Conveyor belt, length||640 m|
|Dwell time||45 minutes|
|No. of tiers||29|
|Drum rotation time||1:30 minutes|
|Contact time, foam||10 minutes|
|Contact time, disinfectant||10 minutes|
For each segment, there is a time overlap of 25% to ensure complete coverage.
The segmented process allows for the proper contact time for detergents, and it ensures that residues do not get transferred to already cleaned surfaces (top-down sequences of rinsing, foam application and disinfecting).
Labour requirements: 1 person
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