Sanitizers

 Sanitizers

Soil that remains on food processing equipment after use is usually contaminated with microorganisms nourished by the nutrients of soil deposits. This contaminant provides a medium for microbial proliferation. A sanitary environment is obtained through removing soil deposits with subsequent destruction of residual microorganisms.

There are different sanitizing agents and application methods. A sterilant is an agent that destroys or eliminates all forms of microbial life. Chemical sterilants include ethylene oxide, glutaraldehyde, and peroxyacetic acid. 

Heat, both dry heat ovens and moist heat such as steam under pressure, or autoclaving is a sterilization process.

A disinfectant is an agent that kills infectious fungi and vegetative bacteria although 

not necessarily bacterial spores on inanimate surfaces. Disinfection is a less lethal process than sterilization. General disinfectants are the major source of products used in house-holds, swimming pools, and water purifiers.

A sanitizer is a substance that reduces, but not necessarily eliminates microbial contaminants on inanimate surfaces to levels that are considered to be safe from a public health standpoint. A sanitizer is effective in destroying vegetative cells.They are categorized as no-rinse food-contact surface sanitizers and non-food-contact surface sanitizers. Food-contact sanitizers include sanitizing rinses for equipment, utensils, and containers used in dairy processing plants, food processing, and beverage plants, and eating and drinking establishments.

A biocide is a substance that provides microbial control of a process (fogging disinfection, disinfection of an aseptic line, or biofilm removal). These compounds are classified as oxidative sanitizer biocides (various halogens), hydrogen peroxide-basedbiocides (peracetic acid, peracids, chlorine dioxide, and ozone), and surfactant-based biocides (acid anionic sul-fonic acid, sulfonated fatty acids, and quater-nary ammonium compounds). Others are chlorohexidine gluconate, phenolics, and alde-hydes (glutaraldehyde and formaldehyde).

SANITIZING METHODS

1. Thermal

Thermal sanitizing is relatively inefficient because of the energy required. Its efficiency depends on the humidity, temperature required, and length of time a given temperature must be maintained. Microorganisms can be destroyed with the correct temperature if the item is heated long enough and if the dispensing method and application design, as well as equipment and plant design, permit the heat to penetrate to all areas.

Temperature should be measured with accurate thermometers located at the outlet pipes to ensure effective sanitizing. The two major sources for thermal sterilization are steam and hot water.

Steam

Sanitizing with steam is expensive and usually ineffective. Workers frequently mistake water vapor for steam; therefore, the temperature usually is not high enough to sterilize that which is being cleaned. If the surface that is being treated is highly contaminated, a cake may form on the organic residues and prevent sufficient heat penetration to kill the microbes. Condensation from this operation and other steam applications has complicated cleaning operations.

Hot Water

Immersion of small components (i.e., knives, small parts, eating utensils, and small containers) into water heated to 800C or higher is another thermal method ofsterilization. The microbicidal action is thought to be the denaturation of some of the protein molecules in the cell. Pouring “hot” water into the containers is not a reliable sterilizing method because of the difficulty of maintaining a water temperature high enough to ensure adequate sterilization. Hot water is an effective, nonselective sanitizing method for food-contact surfaces; however, spores may survive more than an hour at 1000C. Hot water is frequently used for plate heat exchangers and eating utensils.

2. Radiation

Radiation at a wavelength of approximately 2,500 Å in the form of ultraviolet light or high-energy cathode or gamma rays will destroy microorganisms. For example, ultraviolet light has been used in the form of low-pressure mercury vapor lamps to destroy microorganisms in hospitals and homes. UV activity appears to be pH and temperature independent and produces no taste or odor in treated water. It has been found to produce few, if any, undesirable by-products, and little or no mutagenic activity or halogenated by-products. 

3. High Hydrostatic Pressure (HHP)

This technique is applied to foods, which can be liquid or solid, packaged or unpack-aged, to high pressure (which varies depending upon application) usually for 5 minutes or less. HHP can be used on many foods such as raw and cooked meats, fish and shellfish, fruit and vegetable products, cheeses, salads, dips, grains and grain products, and liquids including juices, sauces, and soups. The high pressure does not destroy the food, because it is applied evenly from all sides. Microorganisms living on the surface and in the interior of the food are inactivated. HHP has resulted in the inactivation of certain enzymes that result in the deterioration of food.

4. Chemical Sanitizing

The chemical sanitizers available for use in food processing and foodservice 

operations vary in chemical composition and activity, depending on conditions. 

Generally, the more concentrated a sanitizer, the more rapid and effective its action. 

Because chemical sanitizers lack penetration ability, microorganisms present in cracks, 

crevices, pockets, and in mineral soils may not be totally destroyed. For sanitizers to 

be effective when combined with cleaning compounds, the temperature of the cleaning 

solution should be 550C or lower, and the soil should be light. The efficacy of sanitizers 

(especially chemical sanitizers) is affected by physical–chemical factors such as:

Desired Sanitizer Properties

The ideal sanitizer should have the following properties:

Microbial destruction properties of uniform, broad-spectrum activity against 

vegetative bacteria, yeasts, and molds to produce rapid kill

 Environmental resistance (effective in the presence of organic matter [soil 

load], detergent and soap residues, and water hardness and pH variability)

 Good cleaning properties

 Nontoxic and nonirritating properties

 Water solubility in all proportions

 Acceptability of odor or no odor

 Stability in concentrated and use dilution

 Ease of use

 Ready availability

 Inexpensive

 Ease of measurement in use solution

A standard chemical sanitizer cannot be effectively utilized for all sanitizing 

requirements.

Chlorine Compounds

Liquid chlorine, hypochlorites, inorganic and organic chloramines, and chlorine 

dioxide function as sanitizers. Hypochlorous acid, the most active of the chlorine compounds, appears to kill the microbial cell through inhibiting glucose oxidation by chlorine-oxidizing sulfhydryl groups of certain enzymes important in carbohydrate metabolism. 

Other modes of chlorine action that have been proposed are: (1) disruption of protein 

synthesis; (2) oxidative decarboxylation of amino acids to nitrites and aldehydes;reactions with nucleic acids, purines, and pyrimidines; (4) unbalanced metabolism after the destruction of key enzymes;induction of deoxyribonucleic acid (DNA) lesions with the accompanying loss of DNA-transforming ability; (6) inhibition of oxygen uptake and oxidative phosphory-lation, coupled with leakage of some macro-molecules; (7) formation of toxic N-chlor derivatives of cytosine; and (8) creation of chromosomal aberrations.

Iodine Compounds

Diatomic iodine is the major active antimicrobial agent, which disrupts bonds that hold cell proteins together and inhibits protein synthesis Generally, free elemental iodine and hypoiodous acid are the active agents in microbial destruction. The major iodine compounds used for sanitizing are iodophors, alcohol-iodine solutions, and aqueous iodine solutions. The two solutions are normally used as skin di-infectants. 

The iodophors have value for cleaning and disinfecting equipment and surfaces, and as a skin antiseptic. Iodophors are also used in water treatment.Iodine compounds cost more than chlorine and may cause off-flavor in some products. Other disadvantages of iodine compounds are that they vaporize at approximately 500C, are less effective against bacterial spores and bacteria phage than are chlorines, have poor low-temperature efficacy, are very sensitive to pH changes,and stain porous and plastic materials. Iodine sanitizers are effective for sanitizing hands because they do not irritate the skin. 

Bromine Compounds

Bromine has been used alone or in combi-nation with other compounds, more in water treatment than as a sanitizer for processing equipment and utensils

Quaternary Ammonium Compounds

The quaternary ammonium compounds, frequently called the quats, are used most frequently on floors, walls, furnishings, and equipment. They are good penetrants and, thus, have value for porous surfaces. They are natural wetting agents with built-in detergent properties and are referred to as synthetic surface-active agents. Thus, theycan be applied through foaming. The most common agents are the cationic detergents, which are poor detergents but excellent germicides. 

The quaternary ammonium compounds include alkyldimethylbenzylammonium chloride and alkyl dimethyl ethylbenzylammonium chloride, both effective in water ranging from 500 to 1,000 ppm hardness without added sequestering agents. 

Diisobutylphen-oxyethoxyethyl dimethyl benzyl ammonium chloride and methyldodecylbenzyltrimethyl ammonium chloride are compounds that require sodium tripolyphosphate to raise hard-water levels to a minimum of 500 ppm. 

Acid Sanitizers

Acid sanitizers, which are considered to be toxicologically safe and biologically active, are frequently used to combine the rinsing and sanitizing steps. Organic acids, such as acetic, peroxyacetic, lactic, propionic, and formic acid, are most frequently used. 

Peroxy Acid Sanitizers

The peroxy acid-hydrogen peroxide sanitizers represent a newer class of sanitizers, although they have been used extensively in Europe since the 1970s. Peroxy acid is a strong, fast-acting sanitizer that works on the same basis as chlorine based sanitizers, through oxidation. 

Hydrogen Peroxide

A hydrogen peroxide-based powder in 3% and 6% solutions has been found to be effective against biofilms. This anti-bacterial agent may be used on all types of surfaces, equipment, floors and drains, walls, steel mesh gloves, belts, and other areas where contamination exists. This sanitizer has been demonstrated to be effective against L. monocytogenes when applied to latex gloves 

Ozone

Ozone, a molecule comprised of three oxy-gen atoms, is naturally occurring in the earth’s upper atmosphere. It acts as a powerful and nonselective oxidant and disinfectant, (which indicates that it will attack any organic material that it contacts) and may control microbial and chemical hazards. Common by-products of ozonation are molecular oxygen, acids, aldehydes, and ketones. This sanitizer does not cause a harmful residue or contaminated flavor.

Microbicides

The microbicide, 2-methyl-5-chloro-2-methyl isothiazolone, has potential for the control of L. monocytogenes on product conveyors. This microbicide has been found to be effective against L. monocytogenes when it is incorporated in the use dilution of a con-veyor lubricant at a continuous dosing rate of 10-ppm active ingredient. This biocide kills microorganisms quickly at a pH higher than 9.0, which is typical of most conveyor lubricants.