Basic elements of cleaning and disinfection equipment in food processing and handling (2023)

background

Cleaning and hygiene program.

Since cleaning and disinfection can be the most important aspects of a hygiene program, sufficient time should be allowed to outline the correct procedures and parameters. Detailed procedures should be developed for all food contact surfaces (appliances, utensils, etc.), lighting equipment, refrigeration equipment, and heating, ventilation, and air conditioning (HVAC) systems, and anything else that may affect food safety.

The cleaning frequency must be clearly defined for each process line (ie daily, after production or more frequently if necessary). The type of cleaning required should also be identified.

The purpose of cleaning and sanitizing food contact surfaces is to remove the food (nutrients) that bacteria need to grow and to kill any bacteria present. It is important that cleaned and sanitized equipment and surfaces are drained and stored dry to prevent bacterial growth. The necessary utensils (brushes, etc.) must also be cleaned and stored in a clean and hygienic manner.

The adequacy of cleaning/disinfection procedures should be assessed through evaluation and inspection procedures. Compliance with prescribed written procedures (inspection, swabs, direct staff observation) should be continuously monitored and records kept to assess long-term compliance.

The correct sequence for cleaning/sanitizing food contact surfaces is as follows:

1. Sauber
2. Sauber
3. Sauber
4. Disinfect.

The definition

cleaning

Cleaning is the complete removal of food contamination using appropriate chemical cleaning agents under recommended conditions. It is important that the personnel involved have a working knowledge of the nature of the different types of food contamination and the chemistry of their removal.

cleaning methods

Devices can be classified in terms of cleaning method as follows:

• Mechanical cleaning. It is also often referred to as clean-in-place (CIP). No disassembly or partial disassembly required.
• External cleaning (COP). It can be partially disassembled and cleaned in special COP pressure vessels.
• Manual cleaning. Requires complete disassembly for cleaning and inspection.

disinfection

It is important to differentiate and define certain terms:

• Sterilizerefers to the destruction and statistical elimination of all living organisms.
• Disinfectrefers to inanimate objects and the destruction of all vegetative cells (not spores).
• disinfectrefers to the reduction of microorganisms to a level considered safe from a public health perspective.

Appropriate and approved sanitation procedures are processes and therefore duration or timing and chemical conditions need to be described. The official definition (Association of Official Analytical Chemists) of disinfection of surfaces in contact with food is a process that reduces the level of contamination by 99.999% (5 protocols) in 30 seconds.

The official definition of non-product contact surfaces requires a 99.9% (3 log) contamination reduction. The standard test organisms used arestaphylococcus aureusmiEscherichia coli.

Common types of disinfection include:

• thermal hygieneinvolves the use of hot water or steam up to a specified temperature and contact time.
• chemical disinfectioninvolves the use of an approved chemical disinfectant at a specified concentration and contact time.

chemistry and water quality

Water makes up about 95-99% of cleaning and disinfection solutions. Water functions for the following:

• Refill detergent or disinfectanttowardsand surface
• Transport dirt or contaminantsoutsideand surface.

Contaminants in water can drastically change the effectiveness of a cleaning agent or disinfectant. Water hardness is the most important chemical property that directly affects cleaning and disinfection efficiency. (Other contaminants may affect the food contact surface or affect soil deposition properties or film formation.)

The pH of water generally ranges from pH 5 to 8.5. This area does not have serious consequences for most detergents and disinfectants. However, highly alkaline or highly acidic water may require additional buffering agents.

Water can also contain a significant number of microorganisms. The water used for cleaning and disinfection must be potable and free of pathogens. Water treatment and hygiene measures may be required before use in purification systems. Water contaminants that affect cleaning capabilities are listed in Table 1.

cleaning

Properties of food soils.

Food contamination is generally defined as unwanted material on food contact surfaces. The ground is visible or invisible. The main source of contamination is the food product being handled. However, minerals in wastewater and residues from cleaning products contribute to films left on surfaces. Microbiological biofilms also contribute to the accumulation of dirt on surfaces.

Since the composition of dirt varies widely, no cleaning agent can remove all types. Many complex films contain combinations of food components, oil or surface dust, insoluble cleaning components, and insoluble hard water salts. These films vary in their solubility characteristics depending on factors such as heat exposure, age, dryness, time, etc.

It is important that the personnel involved understand the type of soil to be removed before selecting a detergent or cleaning program. As a general rule, acidic cleaners will remove alkaline (mineral) soils and alkaline cleaners will remove acidic soils and food residues. Improper use of cleaning products can even “set” dirt, making it more difficult to remove (for example, acidic cleaners can precipitate proteins). Many plaques and biofilms require more sophisticated cleaning agents corrected with oxidizing agents (eg, chlorinated detergents) to remove them.

Soils can be classified into:

• soluble in water (sugar, some starches, most salts);
• acid soluble (limestone and most mineral deposits);
• alkali soluble (protein and fat emulsions);
• Soluble in water, alkali or acid.

The physical state of soil deposits also influences their solubility. Freshly precipitated soil in a cool or cold solution tends to dissolve more easily than an old, dried or baked deposit or complex film. Food soils are complex as they contain mixtures of different components. Table 2 presents a general classification of the soil and distance characteristics.

oily soils

The fat is usually present as an emulsion and can usually be rinsed with hot water above the melting point. Stubborn grease and oil residues can be removed with alkaline cleaning agents, which have good emulsifying or saponifying ingredients.

protein based soils

In the food industry, proteins are by far the most difficult contaminants to remove. In fact, casein (one of the main milk proteins) is used in many glues and paints for its adhesive properties. Food proteins range from simpler proteins that are easy to break down to more complex proteins that are very difficult to break down. Heat denatured proteins can be extremely tough.

In general, a highly alkaline detergent with peptizing or solubilizing properties is required to remove protein stains. Wetting agents can also be used to increase the wettability and suspensibility of proteins. In addition to wetting agents, protein films also require alkaline cleaners containing hypochlorite.

carbohydrate-based soils

Simple sugars are easily soluble in warm water and are easy to remove. Individual starch residues can also be easily removed with mild cleaning agents. Starches associated with protein or fat sweeps are generally easily removed with highly alkaline detergents.

Solos based on known minerals

Mineral salts can be relatively easy to remove or form very problematic deposits or plaques. Calcium and magnesium are involved in some of the hardest mineral films. Under hot conditions and alkaline pH, calcium and magnesium can combine with bicarbonates to form highly insoluble complexes. Other difficult deposits contain iron or manganese. Salt films can also cause corrosion on some surfaces. Stubborn salt deposits require an acid cleaner (especially organic acids, which form complexes with these salts) to remove. Sequestering agents such as phosphates or chelating agents are often used in detergents to remove salt films.

microbiological films

Under certain conditions, microorganisms (bacteria, yeasts, and molds) can form invisible films (biofilms) on surfaces. Biofilms can be difficult to remove and often require cleaning products and disinfectants with strong oxidizing properties.

lubricating greases and oils

These deposits (insoluble in water, alkali, or acid) can often be melted with hot water or steam, but often leave a residue. Surfactants can be used to emulsify the residue and make it suspended in water and washable.

Other insoluble soils

Inert dirt such as sand, clay or fine metal can be removed with surfactant-based cleaning agents. Charred or charred material may require organic solvents.

much land

It is important to rinse food contact surfaces before cleaning to remove most of the soluble soil. Heavy deposits will require more detergent to remove. Improper cleaning can contribute to dirt buildup.

the characteristics of the surface

The cleanability of the surface is a primary consideration when evaluating cleaning effectiveness. Surface properties include:

surface composition

Stainless steel is the preferred finish for food equipment and is specified in many government and industry design and construction standards.For example, Sanitary Standards 3-A (Standards for Equipment Used in Milk and Dairy Applications) specifies 300 series stainless steel or equivalent. Other stainless steel grades may be suitable for specific applications (eg 400 series), e.g. B. to handle products with a high fat content, meat, etc.For highly acidic, highly saline, or other highly corrosive products, more corrosion resistant materials (for example, titanium) are generally recommended.

Other "soft" metals (aluminum, brass, copper or mild steel) or non-metallic surfaces (plastic or rubber) are also used for food contact surfaces. Soft metal and non-metallic surfaces are generally less resistant to corrosion and require careful cleaning.

Aluminum is easily attacked by strong acids and alkaline cleaners, rendering the surface no longer washable. Plastics can crack and tarnish from prolonged exposure to corrosive food materials or cleaning agents.

Hardwood (maple or similar) or sealed wood surfaces should only be used in limited applications such as B. as planks or cutting boards, provided the surface is maintained in good repair. Avoid porous wooden surfaces.

Surface finishing

Equipment design and construction standards also specify surface finish and smoothness requirements. The 3-A standards specify a finish that is at least as smooth as #4 for most applications. For high fat products, a less smooth surface is used to allow the product to lift off the surface.

surface state

Misuse or mishandling can result in corroded, cracked, corroded or rough surfaces. These surfaces are more difficult to clean or disinfect and may no longer be washable. Therefore, care must be taken when using harsh chemicals or corrosive food products.

environmental considerations

Detergents can make a significant contribution to waste disposal (wastewater). The main problem is the pH. Many publicly owned wastewater treatment plants limit the effluent pH to a range of 5 to 8.5. Therefore, in applications where strong alkaline cleaners are used, it is recommended to mix the residual water with rinse water (or use some other method) to lower the pH. Caustic soda recycling is also becoming common practice in larger companies. Other concerns include phosphates, which are not tolerated in some regions of the US, and the total load of soil in the waste stream, which contributes to chemical oxygen demand (COD) and biological oxygen demand ( BOD).

Chemistry Two detergents

Detergents and cleaning products often consist of mixtures of ingredients that interact with dirt in different ways:

• Physically active ingredients change physical properties such as solubility or colloidal stability.
• Chemically active ingredients modify soil components to make them more soluble and therefore easier to remove.

Specific enzymes are added in some detergents to react catalytically and break down specific components of food soils.

Physically Active Ingredients

The most important physically active ingredients are surface-active compounds, so-called surfactants. These organic molecules have a general structural characteristic in that part of the structure is hydrophilic (attracts water) and part is hydrophobic (does not react with water). These molecules work in detergents to promote physical cleaning effects through emulsification, penetration, diffusion, foaming, and wetting.

The classes of surfactants are as follows:

• Ionic surfactants are known as ionic surfactants that are negatively charged in aqueous solution.anionicsurfactants On the other hand, positively charged ionic surfactants are mentioned.cationicsurfactants If the charge of the water-soluble part depends on the pH value of the solution, it is called theamphotericsurfactant These surfactants behave likecationicSurfactants in acidic conditions and howanionicSurfactants in alkaline conditions. Ionic surfactants are generally characterized by their high foaming power.
• Nonionic surfactants that do not dissociate when dissolved in water have the broadest spectrum of properties, depending on the hydrophilic/hydrophobic balance ratio. This balance is also affected by temperature.For example, the foaming properties of nonionic detergents are affected by the temperature of the solution. Hydrophobicity and solubility decrease with increasing temperature. At the cloud point (minimum solubility), these surfactants often act as defoamers, below the cloud point they vary in their foaming behavior.

It is common practice to mix surfactant ingredients to optimize their properties. Due to rainfall problemscationicmianionicSurfactants cannot be mixed.

chemically active ingredients

alkaline builders

Highly alkaline cleaning agents (or heavy-duty detergents) use lye (caustic soda) or caustic potash (potassium hydroxide). An important property of these highly alkaline detergents is that they saponify fats: they form soap. These cleaners are used in many CIP systems or bottle washing applications.

Mildly alkaline detergents include sodium, potassium, or ammonium salts of phosphates, silicates, or carbonates. Trisodium phosphate (TSP) is one of the oldest and most effective. Silicates are most commonly used as corrosion inhibitors. Carbonate-based detergents have limited use in food processing due to interaction with calcium and magnesium and film formation.

acid builder

Acidic detergents include organic and inorganic acids. The most commonly used inorganic acids include phosphoric, nitric, sulfamic, sodium sulfate, and hydrochloric acid. Organic acids such as hydroxyacetic, citric and gluconic are also used. Acidic detergents are often used in a two-step sequential cleaning regimen with alkaline detergents. Acid cleaning agents are also used to prevent or remove stone deposits (mineral stone, beer stone or milk stone).

water conditioner

Water conditioners are used to prevent the formation of various mineral deposits (water hardness, etc.). These chemicals are usually sequestering or chelating agents. Sequestrants form soluble complexes with calcium and magnesium. Examples are sodium tripolyphosphate, tetrapotassium pyrophosphate, organophosphates and polyelectrolytes. Chelating agents include sodium gluconate and ethylenediaminetetraacetic acid (EDTA).

oxidizing agent

The oxidizing agents used in the detergent application are hypochlorite (also a disinfectant) and to a lesser extent perborate. Chlorinated detergents are most commonly used to remove protein residue.

enzyme ingredients

Enzyme-based detergents supplemented with enzymes such as amylases and other carbohydrate-degrading enzymes, proteases and lipases are finding acceptance in specialized applications in the food industry.

The main advantages of enzymatic detergents are that they are more environmentally friendly and generally require less energy (less hot water cleaning). The use of most enzymatic cleaners is generally limited to unheated surfaces (eg..,cold milk surfaces). However, new generation enzymatic cleaners (currently under evaluation) are expected to find wider application.

fillers

Bulking agents add bulk or bulk, or dilute hazardous detergent formulations that are difficult to handle. Strong caustic solutions are often diluted with fillers to make handling easier and safer. Water is used as a filler in liquid formulations. Sodium chloride or sodium sulfate are common fillers in powder detergent formulations.

various ingredients

Additional ingredients added to cleaning products may include corrosion inhibitors, glycol ethers, and butyl cellosolve (improve oil, grease, and carbon removal).

disinfect

thermal hygiene

As with any heat treatment, the effectiveness of thermal disinfection depends on many factors, including initial contamination load, humidity, pH, temperature, and time.

vapor

The use of steam as a disinfection method has limited application. It is often expensive compared to alternatives and difficult to regulate and control temperature and contact time. In addition, the by-products of steam condensation can make cleaning operations difficult.

Hot water

Sanitizing with hot water, by immersion (small parts, knives, etc.), spray (dishwasher), or recirculating systems, is commonly used. The time required is determined by the temperature of the water. Typical regulatory requirements (1995 Food Code) for the use of hot water in dishwashing and utensil sanitizing applications dictate immersion for a minimum of 30 seconds. at 77°C (170°F) for manual operation; and a final rinse temperature of 165°F (74°C) for single-temperature, single-tank machines and 180°F (82°C) for other machines.

Many government regulations require a dish surface temperature of 160°F (71°C), as measured by an irreversible register temperature indicator in dishwashers. Recommendations and requirements for hot water hygiene in food processing may vary. The Grade A pasteurized milk ordinance requires a minimum of 170°F (77°C) for 5 minutes. Other recommendations for processing operations are 185°F (85°C) for 15 minutes or 176°F (80°C) for 20 minutes.

The main advantages of hot water disinfection are relatively cheap, easy to use and readily available, generally effective against a wide range of microorganisms, relatively non-corrosive and penetrates cracks and crevices. Hot water sanitation is a slow process that requires a ramp-up time and a cool-down time; may have high energy costs; and has certain safety concerns for employees. The method also has the disadvantages of forming or contributing to the formation of films and shortening the useful life of certain devices or parts thereof (seals, etc.).

chemical hygiene

The ideal chemical disinfectant should:

• Approved for use on food contact surfaces.
• They have a broad spectrum or field of activity.
• rapidly destroy microorganisms.
• be stable under all conditions.
• Be tolerant of a variety of environmental conditions.
• easily solubilize and have some detergency.
• be of low toxicity and corrosivity.
• be cheap

No available disinfectant meets all of the above criteria. Therefore, it is important to evaluate the properties, advantages and disadvantages of the disinfectants available for each specific application.

Regulatory considerations

Regulatory concerns related to chemical sanitizers include antimicrobial activity or efficacy, safety of residues on food contact surfaces, and environmental safety. It is important to follow the rules that apply to each chemical use situation. The US Environmental Protection Agency (EPA) registers chemical and antimicrobial sanitizers for use on food and food contact surfaces, as well as non-product contact surfaces. (Prior to approval and registration, the EPA reviews the efficacy and safety data and product labeling information.)

The US Food and Drug Administration (FDA) is primarily concerned with evaluating residues from the use of disinfectants that may enter the food supply. Therefore, any antimicrobial agent and its maximum use level must be approved by the FDA for direct use on food or food contact surfaces. Food contact approved rinse-free sanitizers and non-product contact sanitizers, their formulations, and use levels are listed inCode of Federal Regulations(21 CFR 178.1010). The United States Department of Agriculture (USDA) also maintains lists of antimicrobial compounds (i.e.,USDA List of Protected Non-Food Contact Substances and Compounds), used primarily in the regulation of meat, poultry, and related products by the USDA Food Safety and Inspection Service (FSIS).

Factors that affect the effectiveness of the disinfectant.

physical factors

surface features.Prior to the sanitizing process, all surfaces should be thoroughly cleaned and rinsed to remove any detergent residue. A dirty surface cannot be disinfected. Since effective hygiene requires direct contact with microorganisms, the surface must be free of cracks, holes, or crevices that could harbor microorganisms. Surfaces that contain biofilms cannot be effectively disinfected.

exhibithion time.In general, the longer a chemical disinfectant is in contact with the surface of the device, the more effective the disinfecting effect will be; Intimate contact is just as important as prolonged contact.

The temperature.Temperature is also positively related to microbial destruction by a chemical disinfectant. Due to the caustic nature of most chemical disinfectants, avoid high temperatures (above 55°C [131°F]).

Concentration.In general, the activity of a disinfectant increases with increasing concentration. However, leveling occurs at high concentrations. A common misconception about chemicals is that "a little is good, more is better." Using sanitizer concentrations above recommendations will not improve it and may in fact be corrosive to equipment and result in reduced cleaning ability over the long term. Follow the instructions on the manufacturer's label.

Solo.The presence of organic matter drastically reduces the activity of disinfectants and can even completely inactivate them. The saying goes, "You can't sanitize a dirty surface."

chemical factors

pH value.Disinfectants are strongly influenced by the pH of the solution. For example, many chlorine-based disinfectants are almost ineffective at pH values ​​above 7.5.

water properties.Certain disinfectants are severely affected by impurities in the water.

inactivadoresOrganic and/or inorganic inactivators can chemically react with sanitizers resulting in non-germicidal products. Some of these inactivators are present in detergent residues. Therefore, it is important that surfaces be rinsed prior to cleaning.

biological factors

The microbiological load can impair the effectiveness of the disinfectant. The type of microorganism present is also important. Spores are more resistant than vegetative cells. Certain disinfectants are more active against gram-positive than gram-negative microorganisms and vice versa. Disinfectants also differ in their effectiveness against yeast, mold, fungus, and viruses.

Certain types of chemical disinfectants

The chemicals described in this document are FDA-approved for use as no-rinse and food contact sanitizers. In food processing plants, they are used as rinse aids, sprayed on surfaces, or circulated through equipment in CIP processes. In certain applications, chemicals are foamed onto a surface or sprayed into the air to reduce air pollution.

Chlorine-based disinfectant

chlorine compounds.Chlorine, in its various forms, is the most widely used disinfectant in food processing and handling. Commonly used chlorine compounds include liquid chlorine, hypochlorites, inorganic chloramines, and organic chloramines. Chlorine-based disinfectants form hypochlorous acid (HOCl, the most active form) in solution. Available chlorine (amount of HOCl present) is a function of pH. At pH 5 almost everything is in the form of HOCl. At pH 7.0, about 75% is HOCl. The maximum allowable level for non-discharge applications is 200 ppm available chlorine, but recommended use levels vary. For hypochlorites, an exposure time of 1 minute at a minimum concentration of 50 ppm and a temperature of 24°C (75°F) is recommended. For every 10°C (18°F) drop in temperature, it is recommended to double the exposure time. For chloramines, 200 ppm for 1 minute is recommended.

Chlorine compounds are broad-spectrum germicides that act on microbial membranes, inhibit cellular enzymes involved in glucose metabolism, have a lethal effect on DNA, and oxidize cellular proteins. Chlorine is active at low temperatures, is relatively inexpensive, and leaves minimal residue or film on surfaces.

Chlorine activity is dramatically affected by factors such as pH, temperature, and organic load. However, chlorine is less affected by water hardness compared to other disinfectants (mainly quaternary ammonium compounds).

The main disadvantage of the chlorine compound is the corrosiveness of many metal surfaces (especially at higher temperatures). Health and safety concerns can arise due to skin irritation and mucosal damage in confined areas. At low pH (below 4.0) the deadly Cl₂(mustard gas) can be formed. Concerns have also been raised in recent years about the use of chlorine as a disinfectant for drinking water and as an antimicrobial agent in direct contact with food (meat, poultry, and shellfish). This concern arises from the participation of chlorine in the formation of potentially carcinogenic trihalomethanes (THMs) under appropriate conditions. Although the benefits of chlorine as a disinfectant far outweigh these risks, it iseson the test bench.

chlorine dioxidechloroxide (ClO₂) is currently being considered as a substitute for chlorine, as it seems more environmentally friendly. stabilized ClO₂It is FDA cleared for most applications in disinfectants or for use as a foam for non-food and environmental contact surfaces. Approval has also been granted for use in gutter waters on fruit and vegetable farms and poultry processing water. ClO₂it has 2.5 times the oxidizing power of chlorine and therefore requires fewer chemicals. Typical application concentrations range from 1 to 10 ppm.

CLO₂The main disadvantages are occupational safety and toxicity. Its highly concentrated gases can be explosive and the exposure risks for workers are greater than those of chlorine. Its rapid decomposition in the presence of light or at temperatures above 50 °C (122 °F) makes in situ generation a proven method.

Iodine

The use of iodine as an antimicrobial agent dates back to the 19th century. This disinfectant comes in many forms and usually comes with a surfactant as a carrier. These mixtures are called iodophors. The most active agent is dissociated free iodine (also less stable). This form is more common at low pH. The degree of dissociation of the surfactant depends on the type of surfactant. The solubility of iodine in water is very limited. The general recommended use for iodophors is 12.5 to 25 ppm for 1 minute.

It is generally believed that the bactericidal activity of iodine occurs through direct halogenation of proteins. Recent theories have focused on cell wall damage and disruption of microbial enzyme activity.

Like chlorine compounds, iodophors have a very broad spectrum of activity: they act against bacteria, viruses, yeasts, molds, fungi, and protozoa. Iodine is highly temperature dependent and vaporizes at 120°F. Therefore, it is limited to lower temperature applications. The extent to which iodophors are affected by environmental factors is highly dependent on the properties of the surfactant used in the formulation. Iodophors are generally less affected by organic matter and water hardness than chlorine. However, the loss of activity is pronounced at high pH.

Iodine has long been used to treat wounds. However, ingestion of iodine gas presents a risk of toxicity indoors. The main disadvantage is that iodine can stain some surfaces (especially plastics).

Quaternary ammonium compounds (QAV)

Quaternary ammonium compounds (QACs) are a class of compounds that have the following general structure (Figure 1):

The properties of these compounds depend on the covalently attached alkyl groups (R groups), which can vary widely. Because QACs are positively charged cations, their mode of action is related to their attraction to negatively charged materials, such as bacterial proteins. It is generally accepted that the mode of action lies in the function of the membrane. The carbon length of the R group side chain is generally directly related to disinfectant activity in QACs. However, due to the lower solubility in QACs composed of long carbon chains, these disinfectants may have lower activity than short-chain structures.

QACs are active and stable over a wide temperature range. Since they are surfactants, they have a certain detergency. This makes them less susceptible to light soiling than other disinfectants. However, heavy soil drastically reduces activity. QACs generally have higher activity at alkaline pH. While the lack of hard water tolerance is often cited as a major disadvantage of QACs compared to chlorine, some QACs are quite tolerant of hard water. The activity can be increased by using EDTA as a chelating agent. QAVs are effective against bacteria, yeasts, fungi, and viruses.

An advantage of QACs in some applications is that they leave a residual antimicrobial film. However, this would be a disadvantage in operations such as cultured dairy, cheese, beer, etc., where microbial starter cultures are used.

QACs are generally more active against gram-positive than gram-negative bacteria. They are not very effective against bacteriophages. Incompatibility with certain cleaning agents makes thorough rinsing after cleaning absolutely necessary. Additionally, many QAC formulations can cause foaming problems in CIP applications.

Depending on use and recommended precautions, QACs present little toxicity or safety hazard. As such they are commonly used as room foggers and room deodorizers. However, care should be taken when handling concentrated solutions or using them as ambient foggers.

anionic acid sanitizer

Like QAC, acid-anionic disinfectants are surface active disinfectants. These formulations comprise an inorganic acid plus a surfactant and are commonly used for diacid rinsing and sanitizing purposes.

While QAVs are positively charged, these sanitizers are negatively charged. Its activity is moderately affected by the hardness of the water. Their low use pH, detergency, stability, low odor potential, and non-corrosiveness make them highly desirable in some applications.

Disadvantages include relatively high cost, well-defined pH activity range (pH 2-3), low activity against molds and yeasts, excessive foaming in CIP systems, and incompatibility with cationic detergent surfactants.

Fatty Acid Disinfectant

Fatty acid or carboxylic acid sanitizers were developed in the 1980s. Typical formulations include fatty acids plus other acids (phosphoric acids, organic acids). These agents also serve the dual purpose of rinsing and acid sanitizing. The main advantage over acidic anions is the lower potential for foaming. These disinfectants have a wide range of activity, are highly stable in diluted form, are stable to organic compounds, and are stable in high temperature applications.

These sanitizers have little activity above pH 3.5 to 4.0, are not very effective against yeast and mold, and some formulations lose activity at temperatures below 50°F (10°C). They can also be corrosive to soft metals and attack certain plastics and rubber.

Peroxide

Peroxides, or peroxide compounds, contain at least one pair of covalently bonded oxygen atoms (-O-O-) and are classified into two groups: the inorganic group, which includes hydrogen peroxide (HP) and related compounds; and the organic group containing peracetic acid (PAA) and related compounds.

Hydrogen peroxide (HP)Although widely used in the medical field, it has found limited application in the food industry. FDA clearance has been granted for the use of HP to sterilize equipment and containers in aseptic facilities.

The main mode of action of HP is to create an oxidizing environment and produce singlet oxygen or superoxide (SO). HP is quite broad spectrum with slightly higher activity against gram negative organisms than against gram positive organisms.

High concentrations of HP (5% and above) can be irritating to eyes and skin. Therefore, high concentrations must be handled with care.

Peracetic Acid (PAA)It has long been known for its germicidal properties. However, it has only found application in the food industry in recent years and is promoted as a potential chlorine replacement. PAA is relatively stable at wear resistances of 100 to 200 ppm. Other desirable properties include lack of foaming and phosphates, low corrosivity, hard water tolerance, and favorable biodegradability. PAA solutions have been shown to be useful in removing biofilms.

Although the exact mode of action has not been determined, it is generally accepted that the reaction of PAA with microorganisms is similar to that of HP. However, PAA is highly active against gram-positive and gram-negative microorganisms. The germicidal activity of PAA is dramatically affected by pH. Any increase in pH above 7-8 drastically reduces activity.

PAA has a pungent odor and the concentrated product (40%) is highly toxic, highly irritating, and highly oxidizing. Therefore, caution should be exercised when using it.

A general comparison of the chemical and physical properties of commonly used disinfectants is shown in Table 3.

references used

Lugar, RL 1995.Make the right choice: cleaners.Ecolab, Inc./Food and Beverage Division, St. Paul, MN.

Barnard, S. Extension. flyers pennsylvania university state

Boufford, T. 1996.Make the right choice: disinfectant.Ecolab, Inc./Food and Beverage Division, St. Paul, MN.

Cordas, B.R. and GR. dychdala. 1993. Disinfectants: halogens, surfactants and peroxides. p. 36-52.Within:PM Davidson and AL Branen, (eds.).antibiotics in food. . . . Marcel Dekker, Inc., New York, NY.

1995 Food Code. US Public Health Service, Food and Drug Administration, Washington, DC.

Class A pasteurized milk, 1995.revision. US Health Service, FDA, Washington, DC.

Marriot, N. G. 1994. Cleaning compounds for effective hygiene. p. 85-113. Disinfectants for effective hygiene. p. 114-166.Food hygiene principles.Chapman & Hall, NovaYork, Nueva York.

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