DOSING OF SANITIZER SOLUTIONS


Accurate dosing is a prerequisite for efficient and cost-effective sanitation. The equipment and procedures which are used to deliver sanitizer solutions vary and depend on the specific application for which they were intended and the industry being serviced.

a. FOOD PLANTS

In large food processing plants, daily clean-up necessitates sanitation of all food contact surfaces. Measured quantities of sanitizer are generally transferred from the drum into a large (500 to 1000 liters) dedicated tote, using a calibrated metering pump. The required volume of water is then added to a predetermined level to make up the end-use solution. The amount of sanitizer which the pump is capable of delivering is based on the volume displaced by each stroke of the pump and the time period that the pump is in actual operation. The volume of each stroke can be adjusted and fine tuned rendering the system capable of dosing accurate and consistent concentrations of sanitizer. More sophisticated equipment (and more expensive) use wall mounted pumps which are electronically connected to water flow meters. As water flows into the dispensing tote, it triggers the pump to operate on an intermittent basis to deliver calibrated quantities of sanitizer, with each transfer to the tote of a predetermined volume of water. This intermittent cycle of dosing provides for a more uniform mixing of sanitizer with water. To insure complete dispersion of sanitizer in solution, large storage tanks also have auxiliary pumps and the capability of recirculating the solution for several minutes.

Since effective sanitization in food processing plants is a crucial step in the over all clean up procedure, the crew leader will usually sample the diluted sanitizer solution using either a test kit or test paper. Once adjustments and verifications, if required are made, the sanitizer solution is applied under low pressure onto the food contact surfaces and the excess is allowed to freely run off. Low pressure applications are preferable since they reduce the risk of generating airborne mists which can cause dislodge bacteria to become airborne and transported over great distances. Following sanitization, a potable water rinse is not required nor is it recommended. Flat horizontal or vertical surfaces can either be air dried or allowed to remain wet. The later method is the preferable one and used more frequently. Leaving the surface wet prevents airborne bacteria which may settle on food processing equipment and tables from surviving therefore decreases the risk of contamination.At start-up of operations during the following shift, the remaining residual sanitizer can be rinsed off prior to handling food products. This is not a mandatory or regulatory requirement since sanitizers used in food processing plants also have clearance for incidental food contact at the concentrations used.

b. SUPERMARKET PROGRAM
The areas within a Supermarket deli, meat and bakery sections are relatively small and the equipment requirements for clean up and sanitation can be carried out with simple equipment. Blades, knives, saws, scrapers, and other small utensils are disassembled from the food cutting or processing equipment and placed into a three compartment sink. First, they are allowed to soak in a detergent solution which is dispensed into the sink through a wall mounted plunger type of hand pump. The components are then rinsed with water in the middle sink and sanitized by immersion into the third, sanitizer-containing compartment. Sanitizer is dispensed into the third sink compartment in a manner similar to that used to dispense detergent.
The stationary portion of the equipment as well as the cutting tables are first cleaned with a high foaming detergent then sanitized with a low level disinfectant such as a quat. The equipment used in this type of operation is usually a commercial version of a garden hose sprayer and using city water pressure as a means of delivering product to the affected surfaces. Water flowing through the hose also creates a partial vacuum within the garden sprayer resulting in sanitizer solution being drawn up and mixing with the water stream as it flows past the garden sprayer’s orifice. Commercial units designed for sanitizer application are accurately calibrated by the manufacturer to dispense a 0.2% solution, which is equivalent to 200 ppm quat (10% active) or 200 ppm available chlorine (10% sodium hypochlorite).
Small, pressurized portable tanks into which a prediluted sanitizer solution has been added also finds use in this application, especially in enclosed areas where sanitizer has to be applied to surfaces that are not readily accessible. Such a system makes use of the pressurized contents to direct a stream of sanitizer over a larger distance than would be possible with a garden sprayer using city water pressure.

c. HOSPITALS AND NURSING HOMES
Large hospitals and nursing homes usually dispense use-solution from stationary, central units; each one located on a separate floor. Frequently these units operate by mechanical action alone and dispense product using the principles encountered above; suction of product as a result of an internal vacuum which is created through the flow of water past an orifice. A typical installation is wall mounted with a single hose connected to the city water input line, and contains from 1 to 5 separate dedicated hoses capable of dispensing several products. Adjusting the orifice diameter at the end of each dispensing hose, results in dilutions varying from 1:256 to 1:20.
To maintain control in small hospitals and nursing homes, 1 to 2 gallon of end use solutions are prepared and then transferred into smaller, trigger sprayer type dispensers which can easily be used by the house keeping staff. Critical areas, such as operating rooms which require high level sanitation, use specialized computer assisted dosing and rinsing equipment.

d. RESTAURANTS
Aside from the routine clean up and sanitization of food contact surfaces and food preparation utensils, the bulk of the cleaning and sanitization in restaurants is in mechanical ware washing. In small restaurants, the dish washing product is usually a powder manually fed into the machine and also provides a source of available chlorine for sanitization. Sufficient product, whether or not needed for the soils encountered must be used in order to provide a residual available chlorine level of 100-200 ppm; a level which is required under most municipal health codes.
In restaurants serving a large number of meals daily, it becomes more economical to meter product into the ware washing equipment via rotary pumps which accurately dispense the quantity of chemical required. The larger ware washing units are equipped with a 3 head rotary pump dispensing unit and each pump is calibrated according to the amount of chemical dispensed per rotation of the pump and the number of rotations per minute. Once properly adjusted, detergent, rinse aid and sanitizer can be accurately dosed at the different required concentrations.

ONSITE PRODUCTION OF CLEANING AND SANITIZERS

AQUAOX Systems produce onsite cleaning and antimicrobial liquids. Through ancillary equipment, these cleaning and antimicrobial liquids are automatically delivered throughout the facility. Users of the AQUAOX System, will receive these liquids by opening designated color-coded faucets installed throughout the facility.

These onsite produced cleaners (NaOH) and sanitizers (HOCL) are capable to replace or significantly reduce the usage of  chemical cleaners and sanitizers resulting in cost-savings and less health risks for the cleaning crew.

In my next blog, I will provide a a brief list of cleaning, sanitizing and disinfecting applications for these onsite produced liquids.  The list also include the recommended dosage and method of usage based on proven science.

For more information, please contact aquaox@comcast.net

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One Response to “DOSING OF SANITIZER SOLUTIONS”

  1. Tera Says:

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