RU2005385C1 - Formula feed disinfection method - Google Patents

Abstract

FIELD: agriculture. SUBSTANCE: free-flowing formula feed (moisture content 12-13% ) is exposed to electromagnetic field (15-80 kV/m) for 0.5-15 min. The relative pulse duration is 0.2-0.8, and formula feed is heated to 50-120 C. EFFECT: higher feed quality. 3 tbl, 8 dwg

Description

 The invention relates to agricultural production and may find application in the disinfection of animal feed, grass meal, etc., to obtain high-quality feed for birds, cattle, pigs.

 A known method of heat treatment of food waste with steam-air mixture before feeding. The influence of heat improves the palatability of the feed, changes some physical and mechanical properties and suppresses the pathogenic microflora.

The disadvantage is that this method reduces the nutritional advantages of feed, as components of flour and protein-vitamin supplements lose their value when processing with hot steam at a temperature of ^about 120 C. Moreover, not ensured allowable contamination rate of feed that leads to disease in animals .

 A known method of processing feed using ultraviolet radiation. The power consumption of the line with an ultraviolet irradiator is 10 kW, the productivity is 0.5-1.0 t / h, the irradiation time is 25-60 seconds, the degree of disinfection is 95-97%.

 The disadvantage is that this method disinfects to a specified extent if the feed is irradiated with a very thin layer, since the penetration depth of ultraviolet rays is very small. It is practically impossible to adapt this method to the processing line for preparing compound feed, with a productivity of at least 2 t / h.

A known method of disinfecting food with electromagnetic fields of ultrahigh frequency. For the purpose of disinfecting the feed is heated to 60-70 ° ^C. The heating time to a temperature of 60 ^{° C} a feed bag weighing 30 kg, depending on the humidity of 5-10 min.

 The disadvantage is that the time of feed disinfection depends on their weight. With the production line, difficulties arise with shielding.

 The objective of the invention is to develop a technology for high-frequency disinfection of bulk feed.

The problem is solved in that loose feed with a moisture content of 12-13% is exposed to an electromagnetic field with a frequency of 1.76-300 ^. 10 ⁶ Hz with an electric field of 15-80 kV / m for 0.5-15 minutes with a duty cycle of exposure pulses of 0.2-0.8, and the temperature of the feed is 50-120 ^about C.

 Compound feed is an insulator. When it is placed in an alternating electromagnetic field, electric charges move due to the polarization of the molecules (mixing current) and the presence of a certain amount of free electrons (conduction current). This movement of charges, accompanied by a change in the position of the particles of the material, causes the conversion of electrical energy into thermal energy, as a result of which the dielectrics are heated. High-frequency heating provides a simultaneous and uniform increase in temperature over the entire cross section of a homogeneous material. With a non-uniform composition of the material (feed and pathogens), individual components are heated in proportion to their electrophysical parameters (ε and tan δ) and this phenomenon is used to implement inventive (selective) heating, i.e., to disinfect feed.

In FIG. Figure 1 shows the dependence of the total microbial number (TBC) on the heating temperature (T) of loose feed at different levels of bacterial contamination of the starting material: 1 - TBC is 10 ⁶ microns. tel. in 1 g; 2 - TBC is 3 ^. 10 ⁶ mk. bodies in 1 g. 3 - OMC is 4 ^. 10 ⁶ mk. tel in 1 g.

 In FIG. 2 - dependence of the total microbial number (TBC) in percent relative to the control on the heating temperature (T) of loose feed at different levels of bacterial contamination of the source material.

 In FIG. 3 - the degree of reduction of the TBC depending on the required minimum heating temperature (T) of the feed in the EMF.

 In FIG. 4 - dependence of the total microbial number (TBC) on the electric field strength (E) with a change in exposure time (t).

 In FIG. 5 - dependence of the heating temperature (T) of bulk feed on the electric field strength (E) with a change in exposure time (t).

 In FIG. 6 - the necessary ratio of variable parameters (time t, frequency f and electric field strength (E) to achieve the minimum fatal dose of exposure (D).

 In FIG. 7 - dependence of the total microbial number in percent relative to the control (TMP) on the exposure time (t 0.5-4.5 min) with an electric field E = 86.21 kV / m.

 In FIG. 8 - heating curve of feed during cyclic exposure to EMF.

 The studies were carried out on feed obtained from the Krasnoyarsk broiler poultry farm after an OKC-15 mixer with a moisture content of 12-13% (which corresponds to GOST).

 Loose compound feed with a moisture content of 12-13% was supplied to the technological device of a high-frequency installation with an oscillatory power of 10 kW and a frequency of 27.12 MHz. The installation allows you to: 1) adjust the interelectrode distance; 2) change the voltage in the capacitor with plane-parallel electrodes; 3) change the duty cycle of the electromagnetic field exposure.

 The electric field is regulated by changing the capacitance of the working capacitor, i.e., the interelectrode distance, as well as by stepwise regulation of the voltage on the capacitor plates. The exposure time of the electromagnetic field is governed by a change in the speed of movement of the transporting feed device, and the duty cycle of the electromagnetic field exposure. The graphs and tables show the total exposure time without a pause. Each high-frequency installation generates an electromagnetic field of a certain resolving frequency (0.44; 0.88. 1.76; 5.28; 13.56; 27.12; 40.68; 81.36; 152.5; 300 MHz).

 Experimental studies of the effect of UHFH on total bacterial contamination were carried out at frequencies of 13.56; 27.12; 40.68; 2375 MHz (microwave), and the results of the study are for a frequency of 27.2 MHz. The ratios of tension and exposure time at other frequencies (0.44; 1.76; 27.12; 300 MHz in Fig. 6) were obtained theoretically based on the required minimum dose of exposure (see table 3).

Research was carried out in three stages. In each stage, 10 experiments were laid in 3 replicates (Table 1 summarizes the average data from 3 replicates). Thus, in order to find the theoretical dependence of the effect of exposure (total microbial number, heating temperature), high-frequency electromagnetic field on variable parameters (electric field strength and exposure time), we used a two-factor experiment of type 3 ² . Therefore, the matrix of active planning of a technological experiment provides for 9 experiments and one experiment - a control variant without processing in the electromagnetic field (see Table 1).

Control options in all three stages had an equal level of seeding. The total microbial number of the first batch of feed was 10 ⁶ microns. bodies in 1 g, the second batch - 3 ^. 10 ⁶ mk. bodies in 1 g, the third party - 4 ^. 10 ⁶ mk. tel in 1 g.

 The results of experimental studies of the process of exposure to a high frequency electromagnetic field on the degree of disinfection of bulk feed are summarized in table. 1, 2, 3.

 At the first stage, we studied the effects of a “weak” electric field on TMP (tension varied between 13.41 - 30.22 kV / m) with varying exposure times over a wider range (30-60 min with a duty cycle of 0.9-0.95 )

The results of studies of the first stage convince that the total microbial number begins to decrease (from 10 ⁶ microns. Bodies per 1 gram) below the permissible level (500 thousand microns. Bodies per 1 gram) with an electric field strength above 15 kV / m and a heating temperature above 40 ^about C (see Fig. 1, 2, 4). In this case, the degree of reduction of the TBC is two times (see Fig. 3). To increase the productivity of the production line, it is necessary to reduce the exposure time, which was provided for in the second stage.

At the second stage of research, the electric field strength varied over a wider range (E = 23.8-86.2 kV / m), but the exposure time was reduced. Now investigated the possibility of reducing the total microbial number in the range of 5-15 minutes with a duty cycle of 0.3-0.8. In this case, the starting material contained OMC - 3 ^. 10 ⁶ mk. bodies in 1 g. The results of the study show that in this range of electric field strength even the minimum exposure time (5 min) reduces the total microbial number to a level below the permissible level (see Fig. 1, curve 2; Fig. 4), with a minimal destructive ⁶⁰ ° C. TBC is decreased 6 times (see. FIG. 3).

At the third stage, the electric field strength was varied in the range of 68.3-99.2 kV / m, and the exposure time was changed in the range of 0.5-4.5 min with a duty cycle of 0.6-0.7. In this case, the original feed contained OMC 4 ^. 10 ⁶ mk. bodies in 1 g. Studies show that TBC can be reduced to a level below the permissible level for the indicated range of electric field strength. Such a disastrous temperature is possible if the exposure time is 2.5 minutes, and the electric field strength is 80 kV / m (see Fig. 5). In this case, the TBC decreases by eight times (see Fig. 3).

 A further decrease in the exposure time (increase in the productivity of the processing line) in this tension range (15-80 kV / m) is possible due to an increase in the frequency of the electromagnetic field, since the dose of EMF exposure is directly proportional to the frequency of the EMF (see Fig. 6) .

D = 0.55 ^. ε ^. tgδ ^. f ^. E ^2. t ^. 10 ^-10 , J / m ³ , (1) where D is the dose of exposure, J / m3;
ε, tg δ - dielectric parameters of bulk feed; (ε = 3.8; tan δ = 0.1);
f is the frequency of the field, electromagnetic, Hz (f = 27.12 ^. 10 ⁶ Hz);
E - electric field strength, V / m (20 kV / m);
t is the time of exposure to EMF, s (t = 600 s).

 (The dose of exposure to EMF is energy absorbed in the form of heat per unit volume of the processed material).

Studies show that TMP begins to decrease below an acceptable level if the dose of EMF is above 136 MJ / m ³ (D = 0.55 ^. 3.8 ^. 0.1x x27.12 ^. 10 ⁶ (20) ^2. 10 ^6. 10 ^-10. 600 = 136 MJ / m ^3), wherein the heating temperature of the feed should be above 50 ° ^C. The optimum temperature is in the range 50-120 ^{° C} (see. FIG. 1). Such values of the heating temperature of the feed can be obtained by exposure to an electromagnetic field of a different frequency with a certain combination of electric field strength and exposure time (see table. 2).

 The theoretical (EMF frequencies of 1.76 MHz, 300 MHz) and experimental (EMF frequencies of 27.12 MHz) results of a study of the effects of EMF on compound feed are given in Table. 2.

The maximum permissible heating temperature ¹²⁰ ° C feed (fodder quality deteriorates above) may, for example be obtained by the following combination of variable parameters (see Figure 5..):
EMF frequency f = 27.12 MHz;
electric field strength E = = 55 kV / m;
exposure time t = 15 minutes

In this case, the dose of EMF exposure is limiting and amounts to D = 0.55 ^. 10 ^-10 3,8x ^x0,1. 27.12 ^. 10 ^6. (55) ^2. 10 ^6. 15 ^. 60 = 1543 MJ / m ³ .

The results of the study with an increase in the frequency of exposure to an electromagnetic field of an ultrahigh frequency f = 23.75 MHz on loose feed with a moisture content of 12-13% and an initial seed rate of 40 ^. 10 ⁵ mk. bodies in 1 g are given in table. 3.

 In addition to the indicated experiments (in Tables 1, 2, 3), studies were conducted to study the effect of EMF on wet feed (with a moisture content of 16–20%, 1st row, Table 3). In this case, the total microbial number decreases, since the wetter the material, the greater the dielectric loss coefficient, the higher the heating rate. However, the parameters characterizing compound feed (protein, for example, is growing, compound feed becomes lumps) is deteriorating. Therefore, it is best to expose the EMF to loose feed with a moisture content of 12-13%.

With an increase in the heating temperature (T) of the bulk feed (see Fig. 1.2), the TBC decreases. And enough to heat the combined feed in EMPVCH to 40 ° ^C, to reduce bacterial contamination in two times, that is. E. To an acceptable level (1st line). To reduce by 6 times (curve 2), it is necessary to heat to 60 ^° C, if 8 times to 90 ^° C (see Fig. 3).

 With increasing electric field, the temperature of the feed increases. The longer the exposure time, the higher the heating temperature, the more the TBC decreases.

Frequency ratio, the electric field intensity and exposure time should be such that the heating temperature of feed was not less than 50 ^C and not more than 120 ^C. When the heating temperature less than 40 ^{° C} level TBC still above the allowable rate. (10 ^о С safety margin). At a heating temperature above ¹²⁰ ° C begin to deteriorate palatability of feed, although TBC close to 0.

 The effective range of electric field strength is 15-80 kV / m. If the electric field is lower than 15 kV / m, then the productivity of the processing line is reduced by increasing the heating time. If the electric field strength is 80 kV / m, then (safety issues worsen), it is necessary to sharply reduce the interelectrode distance and increase the voltage on the capacitor plates. In this case, partial breakdowns may occur, i.e., there is an acceptable level of electric field strength for each dielectric.

The optimal effect is in the range of 0.5-15 minutes. The minimum exposure time of 0.5 min is possible from the point of view of technical performance at a maximum frequency of 1.76-300 MHz and an electric field of 30 kV / m (see Fig. 6). In this case, the heating temperature of feed was ^about 50 C. When the minimum frequency EMF - 0.44 MHz and a maximum level of tension 80 kV / m (see FIG 4..) Exposure time is 38.5 min. But such an exposure time is not desirable, as it leads to low productivity of the production line.

 The range of the optimal frequency of the electromagnetic field lies in the range of 1.76-300 MHz (see Fig. 6). The use of high-frequency generators with an electromagnetic field frequency of 1.76 MHz is possible if an electric field in the material is created above 60 kV / m and the exposure time should be 9-15 minutes.

An electromagnetic field with a frequency of 300 MHz speeds up the process, that is, it increases the productivity of the process line. When using an electromagnetic field with a frequency of 0.44 MHz, the processing time sharply increases while maintaining the same dose of exposure 136 MJ / m ³ .

, (2) где t₁ - время воздействия электромагнитного поля ВЧ;
t₂ - время паузы.To implement the cyclic method of exposure, contactless keys are used. The cycle rate is determined by the formula
ε =

, (2) where t ₁ is the exposure time of the RF electromagnetic field;
t ₂ - pause time.

 In this case, the heating curve of the feed looks like shown in FIG. 8.

 With an increase in duty cycle at a constant load, the heating rate increases. Therefore, at high levels of electric field strength, it is desirable to reduce the duty cycle.

 With rf heating, the thermal conductivity and volume of the material do not affect the heating rate. Consequently, in contrast to the prototype of any thickness, material can be processed.

By selectively heating the disinfecting temperature decreases ^to 50 ° C (at a steam-air treatment of 120 ° ^C), thereby maintaining the quality of feed, flavoring advantages, color, odor, which ensures their high palatability.

 The proposed method of disinfection of feed can be implemented in the production line (OKC - 15. OKC - 30) feed mill. (56) Operation manual for the microwave impulse ZU installation, 1991.

Claims (1)

METHOD FOR DISINFECTING FODDER FEEDS, including exposure to electromagnetic waves, characterized in that loose feed with a moisture content of 12 - 13% is exposed to an electromagnetic field with a frequency of 1.76 - 300 10 ⁶ Hz with an electric field of 15 - 80 kV / m for 0.5 - 15 min with a duty cycle of impact pulses of 0.2 - 0.8, and the heating temperature of the feed is 50 - 120 ^o C.