In many cases, business leaders believe that the cost of cleaning and disinfection is the cost of purchased chemicals (mainly because the expense for them is the only one they see). In fact, chemical means for sanitary treatment account for only about 5% of the costs, the main ones being the cost of labor and water. High-quality cleaning products are more expensive, but their purchase will pay off handsomely due to better results and greater cleaning efficiency.
Within the framework of the sanitary-hygienic measures program, it is traditionally recognized that cleaning leads to the removal of not only contaminants, but also the majority of microorganisms present.  demonstrated a reduction in the number of bacteria on surfaces up to 103 times, while  indicated 102-106 values. Work results CCFRA according to the assessment of well-planned and fully implemented sanitary-hygienic programs on food processing equipment of eight enterprises for the production of chilled products are given in table. 14.1. The results indicate that cleaning and disinfection equally contribute to a decrease in the number of microorganisms deposited on the surfaces, and therefore it is advisable to purchase high-quality cleaning products (due to their ability to remove dirt and microorganisms well).
Unfortunately, there is no cleaning agent that in itself could perform all the functions necessary to facilitate the successful implementation of the cleaning program, and therefore a mixture of various typical components is used as a washing solution or detergent:
♦ surfactants (IIAB);
♦ inorganic alkalis;
♦ Inorganic and organic acids;
♦ complexing compounds.
For most food processing operations, for certain operations it may be necessary to use various cleaning agents. At
Table 14,1. And logarithmic arithmetic average number of bacteria in the food processing equipment before and after cleaning and after disinfecting
|Before cleaning||after purification||after disinfection|
|Arithmetic mean||X 1,32 106||X 8,67 104||X 2,5 103|
|The logarithmic average||3,26||2,35||1,14|
|Number of observations||498||1090||3147|
when fulfilling this requirement, one should take into account the desire to minimize the range of cleaning chemicals in the workplace in order to avoid the risk of mistaken use of another product, simplify the work of safety experts and enable economically viable bulk purchases of chemicals. The nomenclature of chemicals and their purpose are well described, and therefore this chapter provides only a general description of the principles.
Water is the main ingredient in all wet cleaning systems and should be drinkable in quality. Water is the cheapest easily accessible transport medium for flushing and dispersing contaminants. It has a dissolving ability, allowing it to remove ion-soluble compounds (for example, salt and sugar), helps emulsify fats at temperatures above their melting point, and can be used as a kind of abrasive when cleaning under pressure. Water without additives, however, has insufficient wetting ability and cannot dissolve non-ionic compounds.
Organic surfactants are bipolar and consist of long, non-polar (hydrophobic or lyophilic) chains (“tails”) and polar (hydrophilic or lyophobic) “heads”. Surfactants are divided into anionic (including ordinary soap), cationic or nonionic (depending on the charge of their ion in solution), the most common anionic and nonionic surfactants. Bipolar molecules help cleanse by lowering the surface tension of water and emulsifying fats. If surfactants are added to a drop of water on the surface, the polar “heads” break the hydrogen bond of water, thereby reducing surface tension and allowing the drop to spread and moisten the surface. The increase in wettability facilitates the penetration of contamination and surface roughness, and therefore enhances the cleaning effect. Fats and oils are emulsified, since the hydrophilic “heads” of surfactant molecules dissolve in water, and the hydrophobic ends dissolve in fat. If fat is connected to the surface, the forces acting at the fat / water interface lead to the fact that the fat particle forms a sphere (so that its surface is minimized with the available volume), the fat deposition “folds” and is separated from the surface.
Alkalis are useful cleansers because they are cheap, destroy proteins due to the action of hydroxyl ions, saponify fats, and can be bactericidal at high concentrations. Strong alkalis (caustic soda or caustic soda) demonstrate a high degree of saponification and destruction of proteins (although they are aggressive and dangerous for operators), and weak alkalis are less dangerous, but also less effective. Alkaline detergents may be chlorinated (to remove protein deposits), but chlorine at alkaline pH is not an effective biocide. The main disadvantages of alkalis are the precipitation of ions from hard water, the formation of foam with soaps and poor washability.
Acids have weak detergent properties, but are useful for dissolving carbonate and mineral deposits, including hard water salts and protein deposits. As in the case with alkalis, the stronger the acid, the more effective it is: however, it is more aggressive both in relation to equipment and operators. In the production of chilled products, acids are not used as often as alkalis (they are usually used for periodic cleaning).
Complexing compounds (complexones or chelating agents) are used to prevent the subsidence of mineral ions by forming soluble complexes with them. They are mainly used to control water hardness and added to surfactants in order to improve their washability and the ability to destroy deposits. Complexons are most often based on expensive ethylenediaminetetraacetic acid (EDTA), and although there are cheaper substitutes (polyphosphates), the latter are harmful to the environment.
Thus, a general-purpose food detergent may contain a strong alkali for saponification of fats, weaker alkaline filler components, a surfactant to improve wetting, degradation and washability, as well as complexones to combat hard water ions. In addition, the detergent should ideally be safe, tasteless, non-aggressive, stable, environmentally friendly and cheap. The choice of cleaning agent depends on the type of contaminants to be removed and their solubility.
Due to the wide variety of possible food contaminants and the influence of food production conditions (temperature, humidity, type of equipment, time before cleaning, etc.), currently there are no generally accepted laboratory methods for assessing the effectiveness of cleaning substances. Food manufacturers have to make sure that cleaning agents work properly by conducting appropriate field tests.
Table 14.2. The solubility characteristics and cleaning procedures recommended for various types of contamination
|Type of pollution||The solubility characteristics||The recommended cleaning procedure|
|Sugars, organic acid salt,||Water-soluble||Slaboщelochnыe detergentы|
|Foods high in protein (meat, poultry, fish)||Water-soluble alkali soluble Slabokislotorastvorimye||Hlorirovannыe щelochnыe detergentы|
|Starchy foods, tomatoes, fruit||Soluble Partially soluble alkali||Slaboщelochnыe detergentы|
|Fatty products (fats, butter, liquid oil)||Water-insoluble Schelochnorastvorimye||Slightly alkaline detergents; the lack of effectiveness should apply strong alkalis|
|Besieged by heating salts of hard water, milk stone, protein deposits||Water-insoluble acid-soluble||Acid cleaner used periodically|
Although most types of microbiological contaminants are removed at one stage or another as part of the sanitation program, there is a high probability that a significant number of viable microorganisms will remain on any surface. The purpose of disinfection, therefore, is to further reduce the number of viable microorganisms by removing, destroying and / or preventing the growth of microorganisms on the surface between releases of batches of products. The best way to disinfect is to increase the temperature, because it acts not only on the surface of the contamination, but also in depth, is not aggressive, does not depend on the type of microorganism, is easily measured and does not give any residues. However, for open surfaces, the use of hot water or steam is uneconomical, dangerous or impossible, and in these cases they rely more on chemical biocides.
Many chemicals have biocidal properties, but some common disinfectants are not used in food production due to safety problems and foreign tastes (for example, phenolic resins or compounds based on ion-metal complexes). A number of disinfectants are used only limitedly in the production of chilled products and / or for special purposes (for example, peracetic acid (peracetic acid), biguanides, formaldehyde, glutaraldehydes, organic acids, ozone, chlorine dioxide, bromine and iodine compounds). Of the acceptable compounds, chlorine-releasing compounds, quaternary ammonium compounds, amphoterics and mixtures of quaternary ammonium compounds and amphoterics are most common.
Chlorine is the cheapest disinfectant. It can be used as part of hypochlorite (or sometimes in the form of gaseous chlorine) or in substances that release it slowly (for example, chloramine, dichlorodimethylhydantoin). Quaternary ammonium compounds are amphipolar (bipolar) and are cationic detergents derived from substituted salts with a chlorine or bromine anion. Amphoterics are based on glycine and often include an imidazole ring.
In the UK food industry in 1987, of the 145 disinfectants used, 52% were chlorine-based, 37% were quaternary ammonium compounds and 8% were amphoterics. Of these biocides, respectively, 44, 30 and 8 disinfectant brands were used. In Europe, in 1993, the most common disinfectants of open surfaces were quaternary ammonium compounds, and for closed surfaces in contact with liquid, peracetic (peracetic) acid and chlorine. The survey showed that exposed surfaces were usually cleaned with alkaline detergents, which foamed, and then washed with water under medium pressure (250 psi), and closed systems were cleaned by CIP (CIP) with caustic soda, and then with acidic detergents with appropriate washing between these operations. In 1994, a survey of disinfectants approved for use in the German food industry (list DVG) showed that 36% are quaternary ammonium compounds (HOUR), 20% are mixtures of quaternary ammonium compounds with aldehydes or biguanides, and 10% are amphoterics. Later, the synergistic compounds of HOUR and amphoteric have been investigated in the UK, and are now widely used in the production of chilled products.
The characteristics of the most widely used compounds are given in table. 14.3. The properties of the HR / amphoteric mixture are similar to the properties of the starting compounds, but often affect microorganisms more strongly.
In the production of chilled products (especially for mid-shift cleaning and disinfection in high-risk areas), alcohol-based products are widely used. This is mainly done to reduce the use of water for cleaning during production, as well as to prevent the growth and spread of any foodborne pathogens that can penetrate the barriers of high-risk areas. Ethyl alcohol (ethanol) and isopropyl alcohol (isopropanol) have bactericidal and virucidal (but not fungicidal) properties, although they are active only in the absence of organic substances (that is, the surfaces must first be wiped clean and then alcohol is used). Alcohols are most active at a concentration of 60-70% and can be included in mixtures for wiping and spraying. Due to the fact that these alcohol-containing mixtures are harmful to health and dangerous, they are used in small quantities locally.
The effectiveness of disinfectants usually depends on five factors: the presence of interfering substances (mainly organic), pH, temperature, concentration and duration of contact. To some extent, the effectiveness of all disinfectants (especially oxidative biocides) decreases in the presence of organic substances. The latter can interact with disinfectants chemically (so that the latter lose their biocidal ability) or spatially (so that the microorganism
Table 14.3. Characteristics of some universal disinfectants
|Property||Chlorine||TIME||Amfoteriki||Peracetic (peracetic acid)|
|Exposure to microorganisms|
|Develops resistance to microorganisms||—||+||+||—|
|Inactivation organic matter||++||+||+||+|
|Hardness of water||—||+||—||—|
|The potential impact on the environment||++||- / +||- / +||_|
Legend: “-” - lack of effect (or problem); “+” - there is an effect; "++" - there is a significant effect
the low classes are protected from their action). Other interfering substances (for example, cleaning agents) can interact with disinfectants and deprive them of their bactericidal properties, and therefore, all contaminants and chemical residues must be removed before disinfection.
Disinfectants should only be used in the pH range specified by the manufacturer. A classic example of this is chlorine, which dissociates in water and forms HOC1 and an ion OCl. At pH 3-7,5, chlorine is mainly present in the form of HOC1, a potent biocide, although the likelihood of corrosion increases with increasing acidity. At pH above 7,5, most of the chlorine is present in the form of the OS1 ion, which has approximately 100 times less biocidal action than HOC1.
Typically, the higher the temperature, the stronger the disinfecting effect. For most production sites operating at ambient temperature (around 20 ° C) or higher, this is not a problem, since most disinfectants are formulated (and tested) to ensure their proper operation at this temperature. In the production of chilled products, the situation is different. БThe effectiveness of 18 disinfectants with 10 and 20 C was tested and it was shown that for some chemicals (especially HOUR-based products) with 100 C the disinfecting effect was significantly reduced. In connection with these, in a chilled environment, it is recommended to use only products specially designed for use at low temperatures.
In practice, the relationship between the bactericidal effect and the concentration of the disinfectant is non-linear (it has the form of a sigmoid curve). At first, at low concentrations of the disinfectant, microorganisms are difficult to destroy, but with an increase in the concentration of the biocide, a point is reached at which most microorganisms are destroyed. Beyond this point, destroying microorganisms becomes more difficult (due to their stability or physical protection), and some of them can survive regardless of the increase in the concentration of the disinfectant. That is why it is important to use a disinfectant in the concentrations recommended by the manufacturer. Concentrations above this recommended level, as follows from the above, may not affect the bactericidal effect, and their use will only be wasteful, and the use of concentrations below this level can significantly reduce the bactericidal effect.
Sufficient contact time between the disinfectant and microorganisms is probably the most important factor in the bactericidal effectiveness of the disinfectant, which must have access to microorganisms, contact them, penetrate the cell membrane and begin their action to destroy them. Adequate contact time is thus critical for good results, and most general-purpose disinfectants need at least 100 minutes to reduce the number of bacteria in suspension by 000 5 times. There are two reasons for this. Firstly, 5 min is a reasonable estimate of the time it takes for the disinfectant to penetrate vertically or nearly vertically into the machined surfaces. Secondly, when testing the effectiveness of disinfectants in the laboratory, the time in 5 min is selected for ease of testing and, therefore, accuracy in determining the time. For highly resistant microorganisms (spores or molds), the disinfectant must be reapplied to the surface to ensure a longer contact time (15-60 min).
Ideally, disinfectants should have the broadest possible spectrum of action against microorganisms (including bacteria, fungi and viruses), and standard performance tests should confirm this. The range of methods currently available for testing disinfectants falls into two main classes - suspension and surface testing. Suspension tests are useful for determining the overall effectiveness of a disinfectant and for assessing the role of environmental parameters (temperature, contact time, and interfering substances). Under real conditions, however, product contact surfaces kill microorganisms that remain after cleaning and are therefore likely to be fairly firmly attached to the surface. That is why a surface test is more acceptable.
In some Research It has been shown that bacteria that have settled on various surfaces are usually more resistant to bactericides than microorganisms in suspension. In addition, it has been shown that cells developing in the form of a biofilm are more stable. The mechanism of the formation of microorganism resistance in the cells attached to the surface and in the cells of the films is unclear, but can be based on some physiological differences (growth rate, changes in membrane orientation, attachment and formation of the extracellular material surrounding the cell). The influence of physical properties is also possible (for example, on the diffusion of a bactericide to the surface of a cell or material, or on the protection of cells by food product residues, or by the surface structure of the material). However, some claims to increase the resistance of microorganisms attached to the surface can be objected. In real conditions, surface tests do not take into account the possible effects of the environment on microorganisms in the production environment before disinfection (action of detergents, changes in temperature and pH, mechanical stresses), which can affect their sensitivity. Both suspension tests and surface tests have their limitations, and therefore new methods have been developed based on studies of the effects of disinfectants on microorganisms and biofilms attached to the surface in—situ (In situ) and in real time.
In Europe, currently operates standard cENTS 216 for harmonizing disinfectant inspections and a number of other standards. Preferred modern methods for checking disinfectants for the food industry, allowing to determine their bactericidal and fungicidal action in suspension, are set forth respectively EN1276 и EN1650 and food manufacturers must ensure that the disinfectants they use meet these standards. Due to the limited testing of the effectiveness of disinfectants, food manufacturers must always confirm the effectiveness of their cleaning and disinfection programs by checking them under operating conditions, which are carried out either by the manufacturer of the disinfectant or by the food manufacturer.
Disinfectants should not only demonstrate bactericidal properties, but also be safe (non-toxic), without giving extraneous tastes to food products. Disinfectants can get into food by accident (for example, by air or with poor washing), or due to the lack of sophistication of the technology (for example, if it is believed that after their use additional washing is not required). Whether flushing is needed or not is determined in each case. Disinfectants are left on the surfaces to ensure (not yet confirmed) their bactericidal effect on any subsequent microbiological contamination of the surface. At the same time, there is an objection to this practice, since low concentrations of the bactericide that remain on the surface (especially in the case of HR) can lead to the formation of stable populations of microorganisms on the surface.
In Europe, regulations regarding the ability to leave a disinfectant on surfaces without rinsing it off are quite controversial. The Meat Products Directive (95 / 68 / EC) allows disinfectants to be left on the surfaces without rinsing in cases where “instructions for use of such substances indicate that rinsing is not necessary” and the Egg Products Directive (89 / 4377 EEC) And dairy products (92 / A6 / UNDP) require flushing disinfectants with drinking water. There are no special regulations for other product categories, although the general Food Hygiene Directive (93 / 43/EEC) it is stated that “food production managers must identify all the most important production sites critical for food safety and ensure that appropriate safety measures are identified, implemented, and analyzed ...”.
Regarding the instructions on non-toxicity of food products, the regulatory acts are different in different countries, although in Europe the situation will become clearer as the implementation of the EU Directive 98 / 9 / EU regarding the sale of products that have undergone bactericidal treatment and containing requirements for toxicological and metabolic studies. Generally recognized for the food industry, the basic principle of the use of disinfectants is their acute oral toxicity (for rats) of at least 2000 mg per 1 kg of body weight.
It is estimated that approximately 30% of complaints about extraneous tastes of food are related to the cleaning and disinfection methods used. Organoleptic analysis experts classify these flavors as “soapy,” “antiseptic,” and “disinfection.” AT CCFRA two flavors tests have been developed in which food products that have been and are not exposed to disinfectants are compared by a panel of tasters using a standard “triangular” test.
To evaluate “air transport”, a modified odor test of packaging materials is used, in which food products are usually of four types - high in moisture (like melon), low in moisture (like cookies), and high in fat (like cream) and a high protein content (for example, chicken) - is kept over a solution of disinfectant in distilled water for 24 hours
To assess the "surface transfer", a modified test of the transfer of taste from packaging to food products is used, in which food products are placed between two sheets of stainless steel and left on 24 hours. To simulate the situation without washing off the disinfectants, they can be sprayed onto stainless steel sheets and their excess drained. Control sheets are washed only with distilled water. The results of a “triangular” test include a statistical assessment of differences in taste between the control and disinfectant-treated samples, as well as a description of all taste changes.