An estimated 76 million cases of foodborne illness occur each year in the United States, costing between $6.5 and $34.9 billion in medical care and lost productivity (Buzby, J.C. and Roberts, T.1997, WHO statistic).
Because food is biological in nature and is capable of supplying consumers with nutrients, it is equally capable of supporting the growth of contaminating microorganisms. (Scientific Status Summary, Institute of Food Technologists, August 2004 edition).
Of these microorganisms, a few are the following - Salmonella, Shigella, Bacillus cereus, Cronobacter, Enterobacteriaceae.
Biofilms • Bacterial Attachment • Mass with Protective Film (Slime) • Traps Nutrients and Bacteria • Prevents Anti-Microbial Action • Effective Cleaning Required
Surface Tension – surface tension is common in all waters (ever did a back flip off a high dive and hit the water in a half turn? Like hitting concrete!).
Surface Tension – is that component of water that keeps it together, or the attraction of water molecules for each other. So droplet on a surface is beaded. Without surface tension, ducks could not swim, and boats would not float.
Surfactants - in detergents are necessary to achieve effective and efficient cleaning of surfaces. A Surfactant causes the water to spread across the surface in a flat appearance, so the water contacts all surfaces, which aids in cleaning process.
Surfactant – is a surface active agent that makes water “wetter” by reducing the surface tension.
Water Hardness – as water takes its path into the ground as it is absorbed, it picks up and dissolves a combination of minerals and salts from the earth. These minerals are not removed from municipality treatment plants.
Water Hardness – the main component of water hardness is calcium. Soap and calcium particles are naturally attracted to each other, resulting in scum formation.
Detergents – often have components built into them to “bind up” the hardness molecules, such as calcium and magnesium, so that they won’t interfere with the effectiveness of cleaning by causing soap scum. The harder the water, the more detergent will be needed to clean effectively and efficiently; however, detergents can only have so much water conditioning material in their formulas.
Sequestration or Chelation – the removal or inactivation of water hardness particles by the formation of a soluble complex.
Soil must be dispersed into the cleaning solution.
Soil must not be allowed to reattach to the surface.
For this occur, the process must be successful, and include:
Soil and surface must be thoroughly wet for a cleaning compound to help separate soil from surface. The cleaning compound helps loosen the soil from the surface by reducing the strength of the bond between the surface and the soil. Heat and mechanical action (scrubbing, shaking, high pressure spray, etc.) can help reduce the bond.
Enough cleaning solution must be used to dissolve the soil. Some soils do not dissolve in solution, so it is important to break up the undissolved soil into smaller particles so it can be carried away from the surface.
A clean surface should be rinsed or flushed to remove all dispersed soil and cleaning residues.
The type of soil determines which cleaning compound can be used most effectively.
There are also steps of preparing the area, inspecting the area, and drying the area, as well as sampling/testing the area for cleaning success.
The typical tools used in cleaning operations include:
Air (hose), water (hose), low and high pressure sprayers, chemicals, brushes, mops, squeegees, buckets, absorbent cloths/towels, COP tanks, CIP systems, Foaming units (wall mount, portable, and door mounted), scrub pads, microfiber towels, dustpans, brooms, dust mops, alcohol wipes, chlorine/disinfectant wipes, heaters, and blowers.
For any cleaning, the basic main factors include:
Time, Temperature, Mechanical Action, and Concentration of Solution.
This is consistent, whether you are scrubbing with a brush and a bucket of solution, or whether you are running a CIP circuit to clean inside a pipe or vessel.
The following factors are all critical to the overall success of the cleaning effort: the time allotted for surface contact time for rinsing or cleaning, the temperature of the solution, the amount of scrubbing action on the soil, and the chemical concentration of the solution used.
Sanitizers are used immediately after cleaning to reduce pathogenic and spoilage organisms on equipment. Any soil deposits remaining on the equipment after cleaning can reduce the effectiveness of a sanitizer through a dilution effect and reaction of the organic material in the soil with the sanitizing compound.
Sanitizing methods include thermal and chemical sanitizing.
Thermal - is relatively inefficient because of the energy required. Microorganisms can be destroyed with the correct temperature, if the item is heated long enough, and if the dispensing method and application and equipment design permit the heat to penetrate to all areas.
Chemical – most often used in food processing plants. The efficacy of sanitizers is affected by factors such as exposure time, temperature, concentration, pH, equipment cleanliness, water hardness, and bacterial attachment.
Flow Rate = the gallons per minute (GPM) of solution flow.
Laminar flow (in pipe) = x<5 feet per second (FPS), no mechanical action, or “scrubbing” action.
Turbulent Flow (in pipe) = x>5 FPS, so have “scrubbing” or mechanical action.
Pipe velocity is measured in feet per second (FPS).
The velocity creates the cleaning action.
Bernoulli's Principle = (physics) = concept that as the speed of a moving fluid increases, the pressure within that fluid decreases. Concept is also applied to nozzles, where the flow rate is accelerated as the tube diameter is reduced and the pressure drops. If you get misting, the PSI is too high for the orifice size; if dripping, the PSI is too low for the orifice size.
PH Scale – indicates the degree/strength of acidity or alkalinity a specific cleaning or sanitizing product is. It measures the concentration or amount of hydrogen ions. The PH value helps you understand what type of cleaner you are using, or its corrosiveness, but it does not indicate it’s chemical strength.
CONCENTRATION – the strength of a chemical solution must be measured by its concentration. Look at the percentage of a chemical in a solution, or how many ounces per gallon is used in solution to determine its strength.
Standard - 1 ounce per gallon = 7800 PPM = 0.78% solution rate.
Use 4 point shift average, so – 20,000 PPM = 2% solution rate. (Mathematically = 20,000/7800 = 2.56, and then 2.56 x .78 = 1.99%).
If Dilution Ratio is 1:10 = 13 oz. per gallon.
Math = 1:10, and there are 128 oz. of water per 1 gallon, then 10 oz. per 100 oz., and 2.8 oz. per 28 oz., so 12.8, or 13 oz., per 1 gallon.
If Dilution ratio is 1:64 = 2 oz. per gallon.
Math = 1:64, and there are 128 oz. of water per 1 gallon, then 1:64 same as 2:128, or 2 oz. per every 128 oz.
Detergents – a substance used for the removal of soils.
Alkaline Detergents – remove organic soils such as fats, oils, carbohydrates, etc.
Acid Detergents – remove inorganic soils, such as calcium, iron, (minerals) etc.
If a soil contains both organic and inorganic elements, always clean the organic soils first (the alkalies will saponify/create soap to remove the organic deposits), followed by a fresh water rinse, then acid wash/rinse to remove inorganic soils (accumulated mineral deposits).
Chlorine – aggressively goes after and removes the protein soil. Chlorine is also an effective sanitizer, but can be very corrosive to all metals. NEVER mix with ACIDS!
Stainless Steel food processing equipment surfaces such as storage tanks/vessels, lines, etc. are best left in an acidic condition, making them bacteriostatic, a condition where bacteria can not grow.
Preparing for solution mixing, you should ALWAYS add the chemical to a water solution, and NEVER do in the opposite order (ie, water to the chemical).
Passivation – a periodic acid flush may improve the life of all your stainless components. During sanitation, the protective chromium oxide film may be removed from the stainless steel surface. Cleaning with an acid solution, and cleaning the lines with sterile air will passivate the stainless steel, this allows the chromium oxide film to reform, thus extending the life of your system. After welding, to remove remaining iron filaments, it is important to clean with an acid (nitric typically, or citric). This removes the “trash debris” metal and allows the chromium oxide coating to re-establish on the surface.
Temperature – The faster detergent, water, and soil molecules react the more efficient the cleaning becomes. For every rise in temperature of 18 degrees F, the effectiveness of cleaning doubles, to a point. For removal of butterfat in dairy, the standard temp is 140 degrees. At 140 degrees, however, you are into automated systems because over 120 degrees is potentially harmful to touch for people.
Temperature – Pasteurization – at 161 degrees F for 15 seconds, destruction of most pathogens occurs.
Sanitizing Criteria - 170 degrees F at 1 minute pure contact time will kill most pathogens; the legal definition requires 170 degrees F at 5 minutes minimum to qualify as sanitizing for water alone.
CIP (Clean In Place) Principle – to effectively clean in place, there are 4 factors that are critical and that must be maximized: Time, Temperature, Mechanical Action, and Chemical Activity.
Time – the time for pre-rinse, for alkaline or acid wash, for post-rinse, and for sanitizing are all important. Solubility of the soil load, size of vessel or length of line circuit, and amount of build up (organic or inorganic) are all key considerations in determining amount of time for each cycle.
Temperature – the temperature of the water (or solution in water) can effect the rate of cleaning/rinsing (dissolution) and impact amount of time needed.
Mechanical Action – this refers to the scrubbing action you get depending upon the turbulent flow, or pressure, in the circuit. Different sized piping requires different flow rates to achieve optimal agitation. The dairy standard is 5 FPS minimum, with most systems designed for 7-8 FPS.
Chemical Activity – the effectiveness of the cleaning agent can reduce water volumes and time for contact.
A CIP System has some basic components – CIP Supply Tank, CIP Supply Pump, CIP Return Pump, Heat Exchanger, Chemical Feed Systems, RTD, Valves, and electronic/computerized controllers.
CIP Supply Pump – you need and want high pressure on a supply pump because it must overcome the discharge friction in the lines as it pumps the solutions throughout the system for the circuit wash/rinse. So, you want Higher RPM, Higher Pressure, and Lower Volume. A typical Supply pump is centrifugal, with around 3500 RPM. A supply pump always has positive head pressure supply.
CIP Return Pump - you need and want high flow/volume on a return pump because you are pulling water/solution from tanks, to avoid a backing up of solution (bath tub ring) in the tank. A typical Return pump is centrifugal, with around 1750 RPM. A return pump pulls about 10-20% more volume of solution/water than a supply pump. Can use a Liquid Ring Pump, since they are capable of pumping air/water solutions. They require larger horsepower motors however, to pump the same volume/flow.
Cavitation – occurs typically when the inlet port of a pump is restricted. It is the process in which microscopic gas bubbles expand in a vacuum and suddenly implode when entering a pressurized area. Air eliminators are used on Return pumps to compensate for this.
Air Operated Valves – Valves are a device that control the pressure, direction, or rate of fluid flow. Typically have either NO (Normally Open by spring and air closed) or NC (Normally Closed by spring and air opened).
Hydraulic Shock – when pressure is with the stem and the stem slams shut, you get a valve “slamming” effect, which can rattle the pipes and damage the valve and the pipe. To offset this, you can deadhead the centrifugal pump with a burst valve to avoid this slamming effect. It is better, however, to design the circuit flow to avoid this situation entirely.
Sprayballs – used to clean vessels. Drilled holes in the spray head allow for directional pressurized cleaning of tank surfaces.
Heat Exchangers – Shell and Tube style or Plate style – typical for heating the city water/cleaning solution for a CIP system. Usually tied to a boiler for steam as heat source.
RTD (Resistive Temperature Device) – directly reads the return temperature, allows the temperature set point to be set for any value within its range.
CIP Supply Tank – Make up wash tank where initial solution is stored and used for the circuit start. Can be chemically treated in tank, or in line, is heated through exchanger, and sent out for wash cycle.
Chemical Feed Systems – dispensing pumps that introduce the alkaline or acid into the circuit for the washing or sanitizing needs.
Electronic Controller (PLC) – the (typically) computerized Programmable Logic Controller that controls the cycle of the CIP system, where it holds the program recipe for how the circuit runs, what valves open and when, temperature control, flow rates, pump actions, etc.
A typical CIP circuit is 5 FPS at 170 degrees F for about 10 minutes. (Sometimes, because of the size of systems and lines, this varies depending upon system being washed).
The most important component of a cleaning system is the person!