The Chemical Cleaning Sequence Management - Engineering - http://maxpages.com/jpchemical/The_Chemical_Cleaning

THE GENERAL CLEANING SEQUENCE MANAGEMENT

a. Preparing the Area, Equipment and Personnel for Cleaning
b. Pre-cleaning or "physical cleaning"
c. Pre-rinsing
d. Chemical cleaninge. Critical Factors in Cleaning Sucess
f. Rinsing
g. Inspection and re-cleaning, if necessary Preparing the Area, Equipment and Personnel for Cleaning

Proper preparation is necessary to ensure the safety of your employees and the effectiveness of the cleaning. To ensure safety, all electric equipment to be manually cleaned should be disconnected from the power source. In many food processing plants, circuit breakers can be tripped and the power supply effectively "locked out." Some equipment may be rinsed and spray-cleaned when it is running. In this case, workers should be trained to keep their hands away from moving parts that may cause injury. Motors, switches, and other electrical components may require covering; consult the equipment manual or manufacturer if unsure.

A piece of equipment may require disassembly for safety reasons before cleaning. Disassembly also enables cleaning to be more effective by improving accessibility and the employee's ability to see the surface to be cleaned. It is a common practice to put disassembled equipment parts on a table or rack, or in a tub, for cleaning.

The plant environment during cleaning can be hazardous to employees unless proper precautions are taken. Slippery floors, high pressure hot water hoses, and cleaning chemicals can all be dangerous. Workers should dress appropriately for the task of cleaning. Boots with non-skid soles, waterproof aprons and gloves are commonly worn. Ideally, pants should not be tucked into boots because doing so makes it much easier to accidentally pour hot water or a chemical solution into the boot. The label on each container of cleaning chemical should list any special precautions that should be taken when using that chemical. In addition, there should be a Material Safety Data Sheet (MSDS) available for each chemical in use. By law, signs must be posted that inform employees of the MSDS location.

Pre-cleaning or "Physical Cleaning":
The purpose of this step is to remove large pieces of debris so that later use of water and chemicals is more efficient. Pre-cleaning may involve picking up packaging debris, scraping equipment surfaces, and sweeping or squeegeeing the floor. The importance of this step is sometimes overlooked. If done properly, it will save you money by reducing water and chemical costs. Some processors combine pre-cleaning with the next step, pre- rinsing.

Pre-rinsing:
In this step, the surfaces to be cleaned are rinsed with water. Just as in physical cleaning, pre-rinsing removes some debris and reduces the need for chemicals. Generally speaking, the pre-rinse will be more effective if warm or hot water is used because the solubility of many components of the debris is greater at higher temperatures. If excessively hot water is used, there is a risk of "cooking on" the small amounts of protein present in apple residue. Experience and monitoring will guide your choice of water temperature. Once the best temperature is determined, monitoring should be done to ensure that this temperature is actually used. In apple cider plants, the pre-rinse may remove virtually all debris. However, microbial biofilms and/or mineral deposits may remain on equipment. The later step of chemical cleaning should not be skipped without conclusive supporting evidence that it is unnecessary.

Chemical Cleaning:
Cleaning chemicals are intended to lift debris from the equipment surface and keep it suspended in water so that it can be rinsed away. No single cleaning chemical does this effectively under 0 conditions. Instead, we use mixtures that may contain several different chemicals to ensure that the job is done well under normal plant conditions.

1) Water - The cornerstone of chemical cleaning is water. Water used in cleaning should be potable, and low in suspended matter and impurities that might affect odor and taste. Ideally, the water should be low in hardness rninerals. Hard water inhibits the ability of some cleaning compounds to suspend debris and can result in mineral deposits on equipment surfaces.

2) Surface Active Agent (Surfactant) - The major ingredient in most mixtures is a surfactant. Its function is to suspend debris components that normally do not stay suspended in water. Of the three types of surfactants, anionic, nonionic, and cationic, the anionic surfactants are most commonly used.

3) Acid or Alkali - One or more compounds will be included to adjust the pH (degree of acidity or alkalinity) of the cleaning solution. Alkaline cleaners are recommended for high- fat debris, particularly when this debris has been heated. Chlorinated alkaline cleaners are used for removing many different types of debris and work especially well against high- protein debris. Acidic cleaners are very useful for removing mineral deposits. In the apple from the apples and soil can support microbial growth over timecider processing plant, a chlorinated alkaline cleaner is commonly used. An acidic cleaner may be periodically useful if mineral deposits develop. Phosphoric acid and gluconic acid are two acids commonly used for this purpose.

4) Chlorine Compounds - Chlorine-containing compounds are sometimes included in an alkaline cleaning mixture. In this application, the chlorine is intended to react with protein in the residue, with little chlorine remaining to kill microorganisms.

5) Water Softeners - Some cleaning mixtures will contain components, called either water softeners or chelators, that chemically bind water hardness minerals. Examples of chelators include certain polyphosphates, gluconates, and EDTA (ethylenediamine tetra- acetic acid). .

Critical Factors in Cleaning Success

a. Temperature of cleaning mixture
In general, warmer temperatures result in more effective cleaning. Avoid excessively high temperatures that cook debris onto the surface. Regular monitoring of the cleaning mixture temperature and adjusting it as necessary will help you clean more consistently and effectively.

b. Concentration of cleaning mixture
When adding cleaning mixtures to water for use, always follow the manufacturer's directions. Increasing the concentration will usually not proportionally increase the effectiveness of cleaning. The directions are written so that typical amounts of debris can be easily removed. Amateur chemistry experiments with cleaning chemicals are absolutely prohibited. Combining mixtures can result in neutralization of components and loss of cleaning ability, e.g. adding an acid mix to an alkaline mix. Mixing chemicals can also create toxic compounds, e.g. mixing acid and sodium hypochlorite resulting in the release of chlorine gas

c. Force associated with application
Some amount of force is usually necessary to help the cleaning mixture remove soil from a surface. In manual cleaning, the employee provides the force by scrubbing the surface. Aids such as scrub pads are commonly used. These aids should not scratch the surface being cleaned because scratches provide crevices in which bacteria can attach. The major challenge of manual cleaning is to ensure that employees are thorough. High spray cleaning systems provide abundant force for removing soil. Unfortunately, the abundant force in these systems sometimes results in debris being splashed onto already cleaned surfaces. Foaming and gelling systems combine water, a cleaning chemical mixture and air. These systems can be portable or stationary. There is limited force applied to the debris when foam or gel is sprayed onto a surface. Follow-up manual cleaning can be used to add force and effectively remove debris. In a Clean-Out-of-Place (COP) system, items to be cleaned are placed in a vessel that is then closed for mechanical cleaning. An example of COP is in a washing machine. Force is applied via spray jets or agitators. Clean-In-Place (CIP) systems are commonly used in the dairy industry for pasteurizers. They may be appropriate for cider pasteurizers, too. In a CIP system, the cleaning mixture is pumped or sprayed through the equipment without prior disassembly. The force is in the turbulent flow of the cleaning mixture resulting from the pump force or acceleration due to gravity as the liquid runs down equipment sides. washing press clothes

d. Contact Time
Generally speaking, a longer contact time is needed if little force is used in applying the cleaning chemical mixture. For example, foam and gel cleaning applications require a longer contact time than a high pressure spray application.

Rinsing
Once chemical cleaning is done, the cleaning mixture and suspended debris are removed by rinsing. Rinsing should be thorough and is typically done with warrn water to prevent debris from being re-deposited. As with the pre-rinse step, this rinse should be done from the top to the bottom of a given piece of equipment. An easy and rapid way to check if your rinsing is thorough is to touch a piece of pH paper to a freshly rinsed surface. If the color of the pH paper indicates that the pH is dramatically different from the pH of the rinse water, then there are either residues or cleaning chemicals remaining on the surface.

Inspection and Re-Cleaning, if Necessary
This step is sometimes forgotten as employees look forward to the end of the work day. All cleaned surfaces should be visually inspected to be sure that proper cleaning took place. If residues are still visible, then cleaning must be re-done. Off-odors indicate a serious cleaning problem, because odors only become detectable when very large numbers of microbes are present.

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