RU2685863C1 - Method for decontaminating raw material of animal origin - Google Patents

Abstract

FIELD: food industry.SUBSTANCE: invention relates to meat industry and is intended for physical and chemical treatment of meat raw materials. Method comprises decontaminating raw material of animal origin exposure to ultraviolet radiation after primary post-slug treatment with further cooling and refrigerating storage. Exposure to ultraviolet radiation is carried out with power density on the treated surfaces of 10 to 50 mW/cm, radiation dose from 50 to 500 mJ/cmfor 1–50 seconds. Cooling and storage in refrigerating chambers are carried out in conditions providing access to atmospheric air products. Ultraviolet radiation sources used are amalgam or pulsed xenon or LED lamps with reflecting focusing coatings providing power on the source surface of at least 30 mWt/cm.EFFECT: higher efficiency of meat raw material disinfection, long storage life of both raw material and products of its secondary processing.3 cl, 2 tbl, 6 ex

Description

The invention relates to the food industry and is intended for physico-chemical processing of raw meat.

Before slaughter on the skin of healthy animals, the content of microorganisms is approximately 103 CFU / cm ² . As a result of technological operations before slaughter and primary processing of meat, the total microbial contamination of carcass surfaces can increase to 106 CFU / cm ² . Sanitary treatment, including mechanical cleaning (dry or wet toilet) reduces microbial contamination by no more than 90%. Cold processing and storage of meat and meat products at low temperatures is one of the most common methods of canning. The use of cold allows for a long time to maintain the high quality of the product, to transport it from the production sites to the places of consumption. With a decrease in temperature in the meat, the rate of flow of physicochemical and biochemical processes slows down, the metabolism in microbial cells is disturbed. As a result, part of the microflora dies, and some, while in a state of suspended animation, temporarily lose their ability to exert harmful effects. However, the use of cold, even for a long period does not ensure the death of the entire microflora. Moreover, some bacteria can develop at low temperatures. Therefore, cooling does not stop the spoilage of meat, although the development of microflora and, consequently, the processes of decay are sharply slowed down.

In this regard, the selection of effective technologies to reduce the microbial contamination of carcass surfaces before refrigerated storage and recycling is of great importance.

One of the ways to reduce the microbial contamination of carcass surfaces is to treat them with antimicrobial agents (in particular, based on hydrogen peroxide and peracetic acid (NAA). However, the practice of using such substances over the past years has revealed its disadvantages. Disinfection of carcass with hydrogen peroxide working solutions and NAA is not effective enough To solve the problem of contamination and cross-contamination, it is necessary to process such solutions for at least 20 minutes. Existing lines, be it submersible or air apelnye not provide for such a time frame. Thus, by using antimicrobial drugs companies is still a risk that the lack of antimicrobial treatment of carcasses will lead to the culling of entire batches.

где а - толщина обрабатываемого мяса; b - длина; h - расстояние между обрабатываемым объектом и устройством облучения; ϑ - частота электроимпульсного излучения; E - напряженность электрического поля; U - напряжение питания устройства облучения. В качестве мясного сырья могут использоваться только небольшие куски филейного мяса размерами: длиной от 10-12 см, шириной 5-7 см и толщиной 2-3 см. Исходя из размеров мясного сырья, определяют время обработки, которое в среднем составляет 60 мин. Затем мясное сырье укладывают на платформу под излучатель на расстоянии 15-20 см.There is a method of processing raw meat (RU 2489025, class A23B 4/01, 2013) by electrical action by a low-frequency electromagnetic field having an energy higher than the energy of breaking hydrogen bonds in a biological cell and created by triangular unipolar pulses with a frequency of 10-200 Hz, the corresponding resonant the frequency of intramolecular transformations in raw meat, during the time, which is determined by the formula:

where a is the thickness of the processed meat; b is the length; h is the distance between the object being processed and the irradiation device; ϑ is the frequency of electropulse radiation; E is the electric field strength; U is the supply voltage of the irradiation device. Only small pieces of sirloin meat can be used as raw meat: from 10-12 cm long, 5-7 cm wide and 2-3 cm thick. Based on the size of raw meat, the processing time is determined, which averages 60 minutes. Then raw meat is placed on the platform under the emitter at a distance of 15-20 cm.

The disadvantage of this method is that the processing of even small pieces of meat products requires a large (about 60 minutes) exposure time. Really existing production lines for meat processing do not allow for such a processing time frame. This method is difficult to use when processing surfaces of carcasses, because it is difficult to ensure uniform irradiation of carcasses in irregularities, crevices, folds, and UV rays do not penetrate. UV exposure does not have a prolonged effect and does not protect the surface of carcasses from secondary pollution during storage and processing.

The closest in technical solution to the claimed method is a method of disinfecting meat semi-finished product (EN 2262279, CL А23L 3/26, 2005), including exposure to meat semi-finished product by ultraviolet radiation immediately before it is frozen. The radiation wavelength is 240-285 nm, the radiation intensity is 45-60 mW / cm ² , the exposure time is 2-20 seconds. After irradiation, the semi-finished product is frozen at a temperature in the freezer -30-35 ° C for 15-50 minutes in the presence of ozone, at its concentration of 5-15 mg / m ³ . Increasing the degree of sterilization is achieved with additional exposure to ultraviolet radiation immediately after the semi-finished product leaves the freezer.

The disadvantage of the prototype is that in semi-finished products contamination exists not only on the surface, but also in the deep muscle layers, which are not exposed to either UV irradiation or ozone. As a result, the observed effect (reduction in the number of pathogenic microorganisms by 4.875 times) is extremely small. Due to the fact that the UV source (lamp ALC -170/70) is placed at a distance of 150-250m from the product being processed without the use of reflective focusing coatings, the power density on the treated surfaces does not exceed 5 mW / cm ² , which does not allow for the initiation of free- radical processes. Therefore, ozone is suggested as a preservative. The MPC of ozone in the working area is 0.1 mg / m ³ . At the stated required concentrations exceeding the MPC by 50-150 times, complex and costly measures are needed to prevent the ozone from getting outside the freezing chamber, which greatly complicates and, consequently, increases the cost of processing meat without a corresponding level of disinfection.

The problem that the invention is directed to is the development of a simple and efficient method of processing raw meat by UV disinfection and initiation of free-radical processes on the surface, which provide additional disinfection and preservation of products that prolong the refrigerated storage of meat in the presence of air.

The technical results of the invention are: improving the efficiency of disinfection of raw meat, long periods of storage, both of the raw material and the products of its secondary processing.

The problem and the claimed technical result is achieved by the fact that the method of disinfection of raw materials of animal origin is carried out by exposure to ultraviolet irradiation after the initial post-slaughter treatment with further cooling and refrigerated storage. According to the invention, exposure to ultraviolet irradiation is performed with an average power density on the treated surfaces from 10 to 50 mW / cm ² , an irradiation dose of 50 to 500 mJ / cm ² for 1-50 seconds. Cooling and storage in refrigerators are carried out in conditions that provide access to the production of atmospheric air.

Cooling and storage of raw materials of animal origin after ultraviolet irradiation should be carried out at a temperature of from 0 to +6 ^o C, corresponding to the standard storage conditions of chilled meat products.

Ultraviolet irradiation is mainly carried out by amalgam or pulsed xenon or LED lamps with a reflected focusing coating, providing an average power density on the source surface of at least 30 mW / cm ² .

After exposure to ultraviolet radiation, raw materials of animal origin are kept in chambers for cooling and / or storage for at least 12 hours.

Primary post-slaughter sanitary processing of raw meat is carried out according to industry-standard procedures, including wet or dry toilet, immersion or air-drop cooling using peracetic acid solutions or other antimicrobial agents and veterinary inspection.

The use of ultraviolet irradiation for disinfecting meat and meat products is based on their bactericidal action - irreversible damage to the DNA and RNA of microorganisms.

The proposed technology ensures the reduction of microbial contamination of carcass surfaces and their preservation due to UV irradiation of high power density.

UV radiation with a high power density, in addition to traditional bactericidal effects (inactivation due to irreversible damage to DNA and RNA of microorganisms), causes chain free-radical oxidation reactions of unsaturated lipid fatty acids in large quantities contained in meat and skin of animals.

The hydroxyl radicals formed during the peroxidation process have the strongest bactericidal potential for inactivating all types of microorganisms. The end products of peroxidation - organic hydroperoxides - are stable products, providing long-term preservation of processed meat.

Since these products are formed as a result of chain chemical reactions, they also extend to those parts of the surfaces where direct UV radiation does not penetrate.

It is important to emphasize that both hydroxyl radicals and organic hydroperoxides are natural for products of animal origin. In the process of animal life, they are produced by the enzymatic system and perform protective functions (including from microbial contamination).

After slaughter, the enzymatic processes in meat continue, but their intensity (especially at low temperatures) decreases sharply. UV irradiation allows you to initiate oxidative processes in the surface layers of treated carcasses.

UV treatment is carried out after slaughter and primary processing of raw meat. At this stage, microorganisms are only on the surface of the product. In the future, microorganisms can penetrate deep into the muscle layers, which will make UV treatment ineffective.

After UV treatment, the products are placed in the refrigerating chambers in such a way as to allow the surfaces to come in contact with air. The presence of oxygen is a prerequisite for maintaining free-radical reactions that ensure the preservation of products.

The impact of the power density of UV radiation on the treated surfaces is from 10 to 50 mW / cm ² . At a lower power density, threshold conditions for initiating lipid peroxidation are not met. At a higher power density, the concentration of hydroxyl radicals increases and they are recombined (i.e., mutual destruction) with the formation of secondary products: aldehydes and conjugates.

The dose (exposure) of UV exposure is from 50 to 500 mJ / cm ² . At a lower dose, inactivation and conservation are not sufficient. With a larger dose, some vitamins are destroyed, partial denaturation of proteins occurs, the surface of the meat darkens.

With the stated power densities, the required dose is reached in 1-50 seconds of irradiation.

Cooling temperatures from 0 to + 6 ° С are standard for refrigeration and storage chambers used in the industry. Terms of cold storage, depending on the processed products (meat of cattle, pork, poultry, etc.) range from 0.5 to 36 days. With shorter storage periods (less than 12 hours), the reduction of dissemination is not ensured due to free - radical processes. For long periods of storage, damage to the product may occur due to other (unrelated to the growth of microorganisms) mechanisms.

Traditional sources of UV radiation — low-pressure mercury discharge lamps do not allow such conditions to be met due to the low (15 mW / cm ² or less) power density on the surface of such lamps.

The condition for achieving these parameters is the use of UV sources with high (> 30 mW / cm ² ) power density on the source surface (amalgam lamps, pulsed xenon lamps, LEDs, etc.) and / or reflective focusing coatings.

The claimed method is illustrated by the following examples.

Example 1

The company for the slaughter and primary processing of broiler chickens.

Pre-chickens were subjected to a standard post-slaughter procedure (including airborne cooling using a solution of peracetic acid, veterinary examination, carcass division into groups). The carcasses were further subjected to UV irradiation with amalgam lamps. The irradiation power density was 2 mW / cm ² , the irradiation time was 100 seconds, and the radiation dose was 200 mJ / cm ² . After UV treatment, the carcasses were packed, sent to the cooling and long-term storage chamber at a temperature of 0 + 6 ° С for 7 days. Shelf life corresponded to the maximum possible in accordance with the declaration of conformity of the enterprise.

The low power density, which did not allow initiation of lipid peroxidation, was not expected to provide for the conservation of products.

Example 2

The method was carried out analogously to example 1, but UV irradiation was carried out with a power density of 10 mW / cm ² for 20 seconds, an irradiation dose of 200 mJ / cm ² .

This mode is optimal. UV treatment with an optimum power density and an exposure dose of 200 mJ / cm ² made it possible to obtain an almost sterile product with the expected high quality and long shelf life of both the product and its recycled products.

Example 3

The method was carried out analogously to example 1, but UV irradiation was carried out with a power density of 10 mW / cm ² , for 60 seconds, an irradiation dose of 600 mJ / cm ² .

With this treatment, there were obvious changes in the quality of the processed products, namely the darkening of the carcass, a "rancid" odor characteristic of the oxidation of fats. Further storage of carcasses was not provided.

Controlled group of microorganisms - colony-forming mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM).

The results of the examples of the method are shown in Table.

Table 1. QMAFAnM, CFU / cm ³ flush liquid from the surface QMAFAnM, CFU / g of muscles of deep layers After slaughter and primary treatment, before UV irradiation 0.5-2 × 10 ³ Less than 10 After 7 days control 1-3 × 10 ⁵ 0.5-2 × 10 ⁴

After 7 days example 1 2-5 × 10 ⁴ 5-9 × 10 ² After 7 days example 2 The absence of The absence of

Findings:

The control group after 7 days of storage did not meet the requirements of TR CU 021/2011 “On food safety” and TP CU 034/2013 “On safety of meat and meat products - standard KMAFanM in chilled poultry meat - not more than 1 × 10 ³ CFU / g (cm ³ ).

Example 4

Enterprise for the slaughter and primary processing of pork.

Pig half-carcasses were subjected to UV irradiation after the standard preprocessing procedure (including wet toilet and veterinary examination).

UV treatment was performed with a power density of 20 mW / cm ² for 15 seconds, an irradiation dose of 300 mJ / cm ² — this mode corresponds to the optimum one. Next, the half unpacked was sent to the cooling chamber and long-term storage at a temperature of 0 + 4 ° C for 7 days. Shelf life corresponded to the maximum possible in accordance with the declaration of conformity of the enterprise.

Example 5

The method was carried out analogously to example 5, but the half-carcasses were packed in a dense airtight film and sent to the cooling and long-term storage chamber at a temperature of 0 + 4 ° С for 7 days;

In the case of storage of meat without oxygen, when the processes of lipid peroxidation are not implemented, the growth of microorganisms on the surface occurs (their number increases approximately 10 times during storage);

Example 6

The method was carried out analogously to example 5, but the UV treatment was carried out with a power density of 2 mW / cm ² for 15 seconds, an irradiation dose of 30 mJ / cm ² .

Bacteriological analysis of the contamination of the surface of carcasses in the specified mode did not show a decrease in contamination as compared with the control, since the power density is 5 times less than that required for initiating lipid peroxidation, and the radiation dose is 1.7 times less than the optimal dose for effective disinfection, therefore, no further studies of the products treated in this mode have been carried out.

Controlled group of microorganisms - colony-forming mesophilic aerobic and facultative anaerobic microorganisms (QMAFAnM).

The results of examples 4 and 5 are shown in Table.

Table 2. QMAFAnM, CFU / cm ³ flush liquid from the surface Before UV treatment 2-4 × 10 ³ After UV treatment 0.5 - 1.2 × 10 ² After 7 days of storage control 5-9 × 10 ⁴ After 7 days of storage in example 5 1.0 - 1.5 × 10 ³ After 7 days of storage in example 4 absence of

The presented examples prove the direct effect of UV irradiation of the half-carcass surfaces due to inactivation by the mechanism of DNA and RNA damage and amounted to 90-95%, which provides an improvement in the microbiological quality of products after long-term storage. In the case of storage without oxygen access, when the processes of lipid peroxidation are not realized, the growth of microorganisms on the surface occurs.

In the case of storage with oxygen access during storage in the refrigerating chamber, there is a significant decrease in the number of microorganisms (up to their complete inactivation), which indicates a significant contribution of the process of initiation of lipid peroxidation by UV irradiation.

Currently, the claimed method of disinfection of raw materials of animal origin is at the implementation stage.

Claims (3)

1. The method of disinfection of raw materials of animal origin by exposure to ultraviolet irradiation after primary post-slaughter processing with further cooling and refrigerated storage, characterized in that the exposure to ultraviolet irradiation is carried out with a power density on the treated surfaces from 10 to 50 mW / cm ² , the radiation dose from 50 to 500 MJ / cm ² for 1-50 seconds, and cooling and storage in refrigerating chambers is carried out in conditions that provide access to the production of atmospheric air, while as a source Ultraviolet irradiation uses amalgamic or pulsed xenon or LED lamps with reflective focusing coatings that provide at least 30 mW / cm ^{2 of} power on the source surface. 2. The method according to p. 1, characterized in that the cooling and storage of raw materials of animal origin after ultraviolet irradiation is carried out at a temperature of from 0 to + 6 ° C. 3. The method according to p. 1, characterized in that after exposure to ultraviolet radiation, raw materials of animal origin are kept in chambers for cooling and / or storage for at least 12 hours.