PRINCIPLES OF INDUSTRIAL CLEANING

NOONE enjoys being in a dirty environment. This appplies whether one is at home or work place.

A dirty workplace is unsafe and unhealthy. Microorganisms grow and multiply in a dirty environment. They can cause product contamination and diseases to workers. This can be prevented by practicing industrial cleaning.

I once worked in a food and beverage company in production. The company had high plant hygiene standards. It took time for me to appreciate hygiene. Among other duties, I was responsible for ensuring that good plant hygiene is maintained.

As a Chemical Engineer, I was not interested in hygiene issues. Anything to do with microbiology used to put me off. In fact, I avoided studying biology at secondary school because

I found scientific names of microorganisms too difficult for me to pronounce. What I couldn’t pronounce, I couldn’t master. Up to now, I can’t recall from memory and recite more than two microorganisms and the ones I can recall, I doubt if I can spell their names correctly.

Every time the Hygiene Specialist complained about microbiological contamination, it didn’t make sense to me.

To me everything appeared “clean.” Pipes and most machines were made of stainless steels. They never showed any stains. So I concluded that they were clean at all times. But experienced workmates like my manager would easily detect the contamination.

I remember one day he complained that he saw accumulation of biofilms on the conveyors and that he smelled a bad smell, an indication that the equipment was very dirty. When I visited the same location, I neither saw nor smelled anything my manager complained about.

My main focus was achieving high production efficiencies, not high hygiene standards. During production, I would be busy moving around the production area supervising operators to ensure that they performed well.

But during cleaning, in most cases, I would leave operators unsupervised to clean the machines. I thought cleaning was such a simple job that every operator knew what to do. So I would use cleaning time writing reports or doing something else. Whenever plant hygiene tests were conducted, we would get poor results.

The constant poor hygiene results and complaints from my superiors forced me to investigate the root cause and find a solution. After carrying out my personal research, I discovered that my operators didn’t know how to clean properly.

They didn’t even understand why they cleaned and how critical it was to the company. My operators were using poor hygiene practices such as just cleaning visible areas. They would not clean hidden areas where they knew that no supervisor would check.

But when collecting samples, those are the places where the Hygiene Specialist would go to get samples. My operators would use wrong concentration of cleaning chemicals, fail to comply with the required contact time and fail to scrub effectively.

This was an eye opener to me. So I decided to learn as much as I could about plant hygiene. I passed the knowledge I acquired to my operators through training and coaching. I ensured that I supervised cleaning just like production.

Instead of leaving the production area during cleaning, I would be present from start to finish. As a result, hygiene test results improved. My team became consistently best in practicing good hygiene standards.

Industrial cleaning is different from domestic cleaning. Poor plant hygiene standards have serious consequences to the company.

Imagine draining a huge tank of milk just because it is contaminated. This would result in a huge financial loss to the company.

If this company, however, decides to package contaminated milk, it would put consumers at risk. Consumers may sue the company. This can lead to the company being charged a huge fine.

So either way, the company would incur financial loss. After investigation, you may discover that the contamination of the milk was because the tank was poorly cleaned. Such a cause is preventable.

The starting point in improving plant hygiene is to understand what dirt is and how to get rid of it. The amount and type of dirt will determine the method to use in cleaning it. Dirt is simply soil. This soil can be either organic or inorganic sticking to the surface. Examples of organic soils include proteins, fat and yeast. This type of dirt promote the growth of microorganisms as they provide food for them.

Examples of inorganic soils include dust, mud, scales, oils and grease. This type of dirt doesn’t support microbiological growth. It is also important to remember that dirt can be either soluble or insoluble and it can be either visible or invisible. The goal of industrial cleaning is to eliminate all forms of dirt.

A clean workplace is one which is free of inorganic dirt. On the other hand, a hygienic workplace is one which is free of organic dirt. In other words, free of disease-causing microorganisms.

However a hygienically clean workplace which is free of both organic and inorganic dirt. This is accomplished through practicing industrial cleaning.

Cleaning eliminates dirt while sanitisation eliminates microorganisms. Sanitisation is the destruction of microorganisms by killing them or inhibiting their growth. This is achieved in two ways – sterilisation or disinfection.

Sterilisation eliminates all forms of microbiological life such as bacteria, spores, fungi and viruses using chemicals or heat. Disinfection eliminates microorganisms but not spores using chemicals.

During industrial cleaning, you start by cleaning to remove dirt followed by sanitisation to eliminate microorganisms which might remain after cleaning.

There are two major elements involved in cleaning. These are water and the detergent. Once you understand the dirt, the next step is to understand the quality of water suitable for cleaning.

During cleaning, the detergent is dissolved in water. The cleaning solution constitutes 9599 percent water. Therefore the quality of water is vital in the cleaning process.

There are two factors affecting the quality of cleaning water which are crucial in the cleaning process. These are water hardness and the high surface tension. Cleaning water with high water hardness is not suitable for cleaning. The high surface tension affects cleaning negatively as well. Water hardness causes scaling. Formation of water scales increases as the temperature of water increases.

If you are very observant, you must have seen scales in a pot or kettle constantly used at home for boiling water. Water hardness can either be temporal or permanent. Temporal water hardness is caused by calcium bicarbonate while permanent hardness is caused by calcium sulphate or magnesium sulphate and calcium chloride or magnesium chloride.

Cleaning water must be made soft. Using water with high water hardness will result in the formation of scales during cleaning especially at high temperature. Industrial cleaning chemicals contain the chemical called sequestering agents which prevent water hardness.

Water has high surface tension. High surface tension reduces the wetting power of water. This prevents the cleaning solution from penetrating the dirt to dissolve it. The surface tension must be reduced for cleaning to be effective. Cleaning chemicals contain the chemical known as surfactants or wetting agents to reduce surface tension.

Besides understanding dirt and water quality, you also need to understand the quality of detergent. There are different types of detergents available on the market. However you need to choose the detergent correctly. Seek professional guidance.

Detergent used for industrial cleaning is a blend of chemicals, various chemicals put together to solubilise the dirt, remove it from the surface and ensure that it does not re-deposit itself back to the cleaned surface.

Detergents are based on either acids or alkalis substances. Acid-based detergents are suitable to clean soils such as proteins while alkalis-based detergents are suitable to clean soils such as fats.

The cleaning process is as follows. The detergent is dissolved in water to make a cleaning solution. The detergent in the solution penetrates the dirt, dissolves the dirt, holds the dirt in suspension and carries it away during rinsing. The dirt sticks to the surface of the equipment. The detergent must penetrate the dirt, detach it from the surface and keep it in the solution. As mentioned earlier, not all dirt is soluble. So insoluble dirt may still remain sticking on the surface.

To remove such dirt, mechanical action like scrubbing is needed. Scrubbing promotes effective removal of both soluble and insoluble soils.

Soluble dirt is kept dissolved in the solution and insoluble dirt is kept suspended in the solution. The detergent must ensure that both dissolved and suspended dirt do not re-deposit to the cleaned surface.

During rinsing, both the detergent and the dirt must be carried away, nothing must remain. A good detergent must be rinseable.

The effectiveness of cleaning depends on a number of factors. Besides the key elements involved in cleaning – dirt, water and detergent, there are other factors that affect the cleaning process.

The first one is temperature. The higher the temperature, the more effective the cleaning. Hot water requires less detergent while cold water requires more detergent. It also helps to loosen the dirt.

High temperature reduces viscosity and reduces surface tension of cleaning water. High temperature promotes effective sterilisation especially heat sterilisation. The higher the temperature of steam or hot water, the more microorganisms will be eliminated.

The second factor is concentration. The higher the concentration, the more effective the cleaning and sanitisation. When the concentration of the detergent is higher, more dirt will be removed. Similarly when the concentration of the disinfectant or chemical sterilisers, more microorganisms will be eliminated.

The third factor is contact time. The longer the detergent is allowed to be in contact with the dirt, the more effective the cleaning. Enough time is required to allow the dirt to dissolve in the cleaning solution.

Disinfectants and sterilisers must be allow to have adequate contact time with microorganisms in order for the disinfection and sterilisation to be effective respectively. The last one is the mechanical action. As stated, insoluble dirt must be dispersed with the help of mechanical action. Mechanical action helps to detach soils from the surface. This can be achieved by scrubbing or jetting.

The force from scrubbing using brushes will remove the dirt including stubborn ones. This list of factors is not exhaustive. There are many more factors like pH which I have not mentioned due to space limitations.

A hygienically clean workplace is a healthy and safe place. Regardless of the industry, all workplaces must practice good plant hygiene. The degree of cleanness depends on the nature of product you produce.

For example, pharmaceutical and food and beverage companies need high standards of plant hygiene. Products which are sensitive to microbiological spoilage require higher degree of cleanness.

Ensure that you know the propensity of your product to microbiological contamination. Keep your workplace hygienically clean. Until next week, stay safe. Zambia needs you.

The author is the CEO of SafetyFocus, a safety company committed to providing safety trainings, consultancy and supplying of safety products.