2 step cooking

Abstract

The present disclosure relates to a method and system for treating insects or insect larvae, the method comprising a first heating step of heating the insects or insect larvae in a first fluid at a temperature between 40° C. and 105° C., a cooling step of cooling the insects or insect larvae in a second fluid, and a second heating step of heating the insects or insect larvae in a third fluid at a temperature between 40° C. and 105° C., the second heating step being performed after the cooling step.

Description

[Technical field]

[0001] The present invention relates to a method and system for treating insects or insect larvae.

[0002] Insects for food or feed production feed on a wide range of raw materials, from waste materials to be processed, to food waste, to cheap animal feed. These raw materials can be hosts to a wide variety of pathogens that can be harmful to people. Usually, these pathogens are not harmful to the insect itself, but can be harmful to the person who ultimately eats the insect. While most pathogens are killed to a sufficiently safe level by a single cooking or decontamination step, certain pathogens, such as bacillus cereus, can form resistant spores that can survive in extreme conditions. These types of pathogens require more complex and better designed decontamination processes.

[0003] Furthermore, discoloration is quite common during cooking and heat treatment of foodstuffs. In many products discoloration can be tolerated, but in insects the color and appearance of the product is an important factor.

[0004] The present invention has been made in consideration of the above problems. In particular, the present invention provides a method and system for effectively removing more resistant pathogens from insects or insect larvae while preserving certain characteristics of the insects, thereby resulting in a safer and more attractive food product.

[0005] The invention is defined in the independent claims. The dependent claims describe preferred embodiments.

[0006] The present disclosure relates to a method for treating insects or insect larvae, the method comprising a first heating step of heating the insects or insect larvae in a first fluid at a temperature between 40°C and 105°C, a cooling step of cooling the insects or insect larvae in a second fluid, and a second heating step of heating the insects or insect larvae in a third fluid at a temperature between 40°C and 105°C, the second heating step being performed after the cooling step.

[0007] Various embodiments may preferably implement the following features.

[0008] Preferably, at least one of the first, second and third fluids is water or steam. The fluid may also be a gas.

[0009] The fluid may allow efficient heat transfer by being in direct contact with the product, i.e. the insects or insect larvae. Water may be beneficial due to the fact that it does not adulterate the product (e.g. by chemicals or other added substances).

[0010] The first heating step is preferably carried out at a temperature between 75° C. and 105° C. and has a duration preferably between 5 and 15 minutes, more preferably between 8 and 12 minutes.

[0011] In the first heating step, in addition to inactivating the vegetative microorganisms and the larvae themselves (if provided alive), the resistant form of the pathogen, i.e., the spores, are activated so that the spores germinate and become vegetative cells after cooling. If the temperature is too high or too low, the spores will not be activated and will remain spores after cooling. In addition, if there is not enough heating time, the spores will also not be activated. However, the heating time should be as short as necessary, since long heating exposure times have a negative effect on the quality (e.g., color) of the product.

[0012] The cooling step is preferably carried out at a temperature of 10°C to 30°C, more preferably 20 to 25°C, and has a duration of preferably 10 to 45 minutes, more preferably 25 to 35 minutes. After cooling the activated spores to a certain temperature range, the activated spores will germinate after a certain time and become vegetative cells. If the temperature is too low or too high, the activated spores will not germinate. Also, if sufficient cooling time is not provided, the spores will not have enough time to germinate, which may have the effect that the spores will not be inactivated in the second heating step. Giving the product more cooling time than is required for spore germination reduces the efficiency of the process, since the cooling equipment is occupied longer than required.

[0013] The second heating step is preferably performed at a temperature between 75°C and 105°C and has a duration between 10 seconds and 5 minutes, preferably between 10 seconds and 1.5 minutes. In the second heating step, the vegetative cells of the pathogen resulting from the germination of the spores during cooling are inactivated. Inactivation of these vegetative cells occurs at the appropriate combination of temperature and time. The higher the temperature, the shorter the time to achieve the same inactivation characteristics. Exceeding the upper limit of the temperature and time range will have a negative effect on the quality of the product. At temperatures below 75°C, very long exposure times will be required, resulting in inefficient use of processes and equipment. The lower limit of 10 seconds on the heat exposure time was chosen because it can still be measured well and is effective, and is a requirement in industrial operations.

[0014] At higher temperatures, shorter times for the heating step can be applied to inactivate pathogens.

[0015] The method may be performed automatically. On an industrial scale, steps should be performed automatically rather than manually, as this helps to keep labor costs at a lower level.

[0016] The first heating step and / or the second heating step and / or the cooling step may involve dispersing the insects, especially to prevent the insects or larvae from forming clusters and thus clogging the equipment. Heat treatment requires that a combination of temperature and time is applied at all points of the product. Dispersing the insects helps to reduce the distance from the surface to the center of the product, thereby taking less time to achieve the desired temperature throughout the product. Furthermore, dispersing the insects allows air to reach the insects, preventing the growth of anaerobic bacteria (e.g. Clostridium spp.).

[0017] The method may further comprise separating the insects or insect larvae from the fluid after the first heating step and / or the cooling step and / or the second heating step. Using different fluids in different steps helps to save energy, since only the product needs to be brought to a new temperature, and not the fluid. In addition, the fluid also removes contaminants (e.g. frass residues) that may be attached to the surface of the larvae. Thus, when the larvae are separated between steps, the contaminants are not carried over from one fluid to the other.

[0018] Preferably, the larvae are stored in a buffer tank after the second heating step. After the second heating step, there may be further processing of the larvae (e.g. drying, freezing). The ability to store the larvae in a buffer time allows for decoupling of the inactivation from further processing, thus allowing for greater operational flexibility.

[0019] Additional insects or insect larvae may be added in the second heating step. Not all larvae may contain spores. These larvae only require inactivation of vegetative pathogens, which is achieved by the second heating step. Allowing the addition of larvae before the second heating step allows insect producers to simultaneously process larvae with and without spores.

[0020] Preferably, the larvae are transported by a pump between the first heating step, the cooling step and the second heating step, preferably together with a fluid. The fluid acts as a buffer and minimizes direct interaction of the larvae with the hard surface. Therefore, the transport of the larvae in the fluid ensures a gentle transport from one device to the other.

[0021] The method can be carried out with live or dead insects or insect larvae. If insects are added live, the first heating step inactivates the larvae very quickly, in addition to the function related to food safety. Rapid inactivation is required from an animal welfare point of view. However, other techniques for inactivation of the larvae may be carried out before the two-step cooking process.

[0022] The method may further comprise an additional heating step prior to the first heating step. Preferably, this heating step is performed at a temperature between 90°C and 110°C. When using live insects, the first heating step simultaneously inactivates the larvae and activates the spores. However, live larvae are inactivated more quickly at higher temperatures. The larvae may be added in an amount such that the liquid is cooled from an initial temperature of 100°C (desirable for rapid killing) to a temperature desired for spore activation. If the inactivation of the larvae is to be decoupled from the activation of the spores, an additional heat treatment step is required.

[0023] Insects or insect larvae are preferably kept in water for at least 50% of the processing time, more preferably at least 80%.Keeping larvae in water ensures uniform temperature distribution and ensures that larvae do not come into contact with oxygen from air, thus preventing discoloration due to fat oxidation.In addition, when kept in water, larvae are better protected from damage caused by hitting hard surfaces.Last but not least, keeping larvae in water allows them to be pumped, which makes it easier to transport them from section to section.

[0024] The disclosure further encompasses a system for treating insects or insect larvae using the method described above, comprising a first, second and third treatment tank, each tank configured to contain insects or insect larvae in a first, second and third fluid, respectively. The first treatment tank comprises heating means for heating and / or maintaining the first fluid at a temperature between 40°C and 105°C. The second treatment tank comprises cooling means for cooling the second fluid, and the third treatment tank comprises heating means for heating and / or maintaining the third fluid at a temperature between 40°C and 105°C. The system further comprises a pump for transporting the insects or insect larvae from the first tank to the second tank and the third tank. The system allows for a continuous process to achieve a safe product with reduced spore counts. [Brief description of the drawings]

[0025] In addition to the above embodiments and associated advantages, the present invention will be further described with reference to the accompanying drawings, in which: [Figure 1] 1 illustrates a basic configuration of an exemplary embodiment of the present disclosure. [Diagram 2] 1 illustrates a configuration of an exemplary embodiment of the present disclosure.

[0026] FIG. 1 shows a basic configuration of a method for treating insects or insect larvae according to the present disclosure. In the drawing, the method includes a first heating step S1 performed in a first fluid at a temperature between 40° C. and 105° C. Preferably, the first heating step is performed at 75° C. to 90° C., more preferably at 80° C. It is possible to use water at a temperature of 100° C., and the temperature is reduced to around 80° C. when the cooled larvae are added. The larvae can be kept at a temperature of 80° C. for 10 minutes to induce sporulation. The insects or insect larvae are then cooled in a second fluid in a cooling step S2, and after step S2, are heated in a third fluid in a second heating step S3 at a temperature between 40° C. and 105° C. Preferably, the second heating step is performed at 80° C. to 95° C., more preferably at 90° C. The temperatures and exposure times of the first heating step S1 and the second heating step S3 may be the same or different from each other. However, the sporulation temperature and the inactivation temperature of the vegetative cells do not have to be the same.

[0027] The fluid may be water in any of its condensed states, or a suitable gas. The first and third fluids may be water or steam. The second fluid may be water or gas that is introduced into the cooling tunnel. In the present disclosure, insects or insect larvae may be used, which may be processed in a dead or live state. Furthermore, the terms "heating step" and "cooking step" may be used interchangeably.

[0028] The method may further comprise an initial heating step prior to the first heating step S1, carried out at a temperature between 90° C. and 110° C., preferably 100° C. This initial heating step rapidly inactivates and kills the larvae, which is preferred from the standpoint of animal welfare.

[0029] The cooling step S2 may be carried out at a temperature between 10°C and 30°C, preferably between 20 and 25°C. The first heating step S1 may have a duration between 5 and 15 minutes, preferably between 10 minutes. The cooling step S2 may have a duration between 10 and 45 minutes, preferably between 30 minutes. The second heating step S3 may have a duration between 10 seconds and 5 minutes, preferably between 10 seconds and 1.5 minutes.

[0030] Insects or insect larvae, in particular live insects or insect larvae, may be dispersed during at least one of steps S1, S2, S3 above, thereby preventing clustering of the animals. For this purpose, a vibrating spreader, an agitator (if the insects are stored in a liquid), or another suitable means may be used.

[0031] The insects or insect larvae may be separated from the fluid after the first heating step S1 and / or the cooling step S2 and / or the second heating step S3. In the case of water, a water separator may be used as described below.

[0032] The insects or insect larvae may be stored in a buffer tank after the second heating step S3. Further insects or insect larvae may be added in the second heating step S3. The insects or insect larvae may be transported between the first heating step, the cooling step and the second heating step by a pump, preferably together with a fluid. Alternatively, an elevator or a conveyor belt may be used.

[0033] The method may also be performed automatically.

[0034] According to the basic method described with reference to Fig. 1, the present disclosure encompasses a corresponding system for treating insects or insect larvae, preferably using the method described above. The system comprises a first, a second and a third treatment tank, each tank configured to contain insects or insect larvae in a first, a second and a third fluid, respectively. The first treatment tank comprises heating means for heating and / or maintaining the first fluid at a temperature between 40°C and 105°C. The second treatment tank comprises cooling means for cooling the second fluid. The third treatment tank comprises heating means for heating and / or maintaining the third fluid at a temperature between 40°C and 105°C. The system further comprises a pump for transporting the insects or insect larvae from the first tank to the second tank and from the second tank to the third tank. The above temperature ranges and specifications of the fluids and further configurations apply equally.

[0035] Alternatively, the system may comprise one tank whose temperature may be varied according to a first heating step, a cooling step and a second heating step.

[0036] In further embodiments, the system may include pipes or belts that heat and cool the larvae during transport with a fluid or gas.

[0037] Figure 2 shows a further exemplary configuration of the present disclosure consistent with the above description. In its largest configuration, the present disclosure encompasses a method and corresponding system means including a first cooking step 2 (first heating step S1) that can be performed using dead larvae 10 and / or live larvae 11 or insects, respectively. In this example, water is used as the fluid. The first cooking step 2 can also act as a killing step, where a diffusion device is required to ensure that the larvae are homogenous and not clumped.

[0038] After cooking, the larvae may be cooled in a cool bath 3 (cooling step S2), pumped 31 to a water separator 4 and / or provided to the water separator 4 by other means. In particular, the larvae may be suspended in a cooling fluid up to the water separator 4 or may be moved using gravity or mechanical means such as a screw or elevator that can transport the larvae without destroying them. Optionally, water may be recirculated from the water separator 4 to the cool bath 3 by a pump (not shown). The cooling bath 3 contributes to the insects or insect larvae not discolouring.

[0039] The larvae are then subjected to a cooking step 5 (second heating step S3) to obtain the final cooked larvae 6. Further live larvae 11 or dead larvae 10 may be added to the cooking step 5 or the process may start from the cooking step 5, i.e. without any pre-treatment.

[0040] The cooked larvae 6 may then be cooled 7 by air, water mist or another suitable fluid to obtain the final product 8. A portion of the cooked larvae 6 or all of the cooked larvae 6 may be transported to a buffer tank 61. The larvae may be stored in water, in another suitable fluid or without added fluid. A pump 62 may be provided to transport the larvae or the larvae together with water to a water separator 63. Optionally, the fluid may be recirculated to the buffer tank 61 by a pump (not shown).

[0041] Further cooking steps, i.e. before and / or after the first cooking step 2 (S1), may also be carried out at similar temperatures as the final cooking step 5 (S3), but for a longer period. The flow diagram of Figure 2 as explained above shows the second cooking step 5 and cooling step 7 required for successful eradication of bacillus cereus, a common pathogen found in insect raw materials. The times for any of these steps could be, for example, 10 minutes at 80°C for step 2 (S1), 30 minutes at 25°C for step 3 (S2), and 3 minutes at 75°C for step 5 (S3).

[0042] However, times longer than 45 minutes in the cooling bath can usually result in regrowth of pathogens and production of (heat-stable) toxins by desporulated pathogens. Cooking temperatures between 40°C and 75°C can also be used, but the corresponding cooking times must be increased. Temperatures above 75°C result in shorter cooking times.

[0043] The pump, buffer and water return loop are all optional steps that can be used in different scenarios. For example, in the complete system shown in Figure 2, the larvae can be pumped across a forklift isle after the cooling bath 3. A final buffer 61 then allows further processing steps to be carried out as a batch rather than continuously.

[0044] [Table 1]

[0045] Thus, the one-step cooking configuration utilises dead larvae 10 that are cooked 5 (i.e. without pre-treatment 2, 3, 31, 4) and cooled 7 to obtain the final product 8.

[0046] The two-step setup according to this example uses dead larvae 10 which are cooked in a first cooking step 2 and cooled in a cold bath 3, after which the water is separated in a water separator 4. The larvae are then exposed to a second cooking step 5, i.e. S3, followed by cooling 7.

[0047] The two-step cooking configuration with larvae killing utilizes live larvae 11, which are prevented from clustering by a vibrating spreader such as a vibrating sieve. After the larvae are killed in the cooking step 2, they are cooled 3, separated from the cold water 4, heated 5 for a second period of time and then cooled 7 to obtain the final product 8.

[0048] A vibrating spreader may optionally be deployed before the larvae are added to one of three main steps (first cooking step, cooling step, second cooking step). In particular, in the case of live larvae, the vibrating spreader ensures that the quickest possible inactivation of the larvae occurs.

[0049] The two-step cooking configuration with pumping of the larvae comprises a cooking step 2, cooling 3, pumping of the larvae 31 with optional water recirculation to a water separator 4, followed by a second heating step 5 and then cooling 7.

[0050] The two-step cooking setup with buffer of larvae includes a first cooking step 2, i.e. S1, a cold bath 3, i.e. S2, a water separation 4, and a further cooking step 5, i.e. S3. The cooked larvae 6 are then stored in a buffer tank 61 and pumped by a pump 62 to a water separator 63 to obtain the product 8. Optionally, the water may be recirculated.

[0051] However, other configurations may be possible and the above table should not be considered limiting.

[0052] According to the present disclosure, a method and system for the treatment of insects or insect larvae is provided that effectively eliminates pathogens and prevents their growth while preserving food product properties such as color. It is therefore possible to eliminate resistant forms of pathogens, i.e. spores, which are usually difficult to control in one-step heating processes. Furthermore, the present disclosure provides an almost immediate insect killing step, which in turn is in line with animal welfare considerations. The method and system can also be performed continuously or using a buffer tank, thus allowing production in both continuous and batch-run operations.

[0053] Other aspects, features, and advantages will become apparent from the above summary and the following description, including the drawings and claims.

[0054] While the present invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. It will be understood that changes and modifications may be made by those skilled in the art within the scope of the following claims. In particular, the present invention encompasses further embodiments with any combination of features from the various embodiments described above and below.

[0055] Moreover, in the claims, the word "comprising" does not exclude other elements or steps, and the indefinite articles "a" or "an" do not exclude a plurality. A single unit may fulfill the functions of several features recited in a claim. Terms such as "essentially," "about," "approximately," and the like, in connection with an attribute or value, also specifically define that attribute exactly or that value, respectively. Any reference signs in the claims should not be construed as limiting the scope.

Claims

1. 1. A method for treating insects or insect larvae, comprising: a first heating step in which the insects or insect larvae are heated in a first fluid at a temperature between 40°C and 105°C; a cooling step of cooling the insects or insect larvae in a second fluid; a second heating step of heating the insects or insect larvae in a third fluid at a temperature between 40°C and 105°C, the second heating step being carried out after the cooling step; A method comprising:

2. The method of claim 1 , wherein at least one of the first fluid, the second fluid, and the third fluid is water or steam.

3. The method according to claim 1 or 2, wherein the first heating step and / or the second heating step is carried out at a temperature of from 75°C to 105°C.

4. The method according to any one of claims 1 to 3, wherein the cooling step is carried out at a temperature between 10°C and 30°C, preferably between 20 and 25°C.

5. the first heating step has a duration of 5 to 15 minutes, preferably 8 to 12 minutes; and / or the cooling step has a duration of 10 to 45 minutes, preferably 25 to 35 minutes; and / or said second heating step having a duration of 10 seconds to 5 minutes, preferably 10 seconds to 1.5 minutes; The method according to any one of claims 1 to 4.

6. The method according to any one of claims 1 to 5, which is carried out automatically.

7. 7. A method according to any one of claims 1 to 6, comprising spreading the insects or insect larvae during the first heating step and / or the second heating step and / or the cooling step.

8. 8. The method according to any one of claims 1 to 7, further comprising separating the insects or insect larvae from the fluid after the first heating step and / or the cooling step and / or the second heating step.

9. 9. The method according to any one of claims 1 to 8, further comprising storing the insects or insect larvae in a buffer tank after the second heating step.

10. A method according to any one of claims 1 to 9, wherein further insects or insect larvae are added in the second heating step.

11. 11. The method according to any one of claims 1 to 10, wherein the insects or insect larvae are transported between the first heating step, the cooling step and the second heating step by a pump, preferably together with the fluid.

12. The method according to any one of claims 1 to 11, carried out with live or dead insects or insect larvae.

13. A method according to any one of the preceding claims, wherein the method further comprises an additional heating step prior to the first heating step, preferably said heating step being carried out at a temperature of from 90°C to 110°C.

14. A method according to any one of the preceding claims, wherein the insects or insect larvae are kept in water for at least 50% of the treatment time, preferably at least 80%.

15. A system for treating insects or insect larvae using a method according to any one of claims 1 to 14, comprising first, second and third treatment tanks, each tank adapted to contain insects or insect larvae in a first, second and third fluid respectively; said first treatment tank comprising heating means for heating and / or maintaining said first fluid at a temperature between 40°C and 105°C; the second treatment tank comprises a cooling means for cooling the second fluid; said third treatment tank comprising heating means for heating and / or maintaining said third fluid at a temperature between 40°C and 105°C; The system further comprises a pump for transporting the insects or insect larvae from the first tank to the second tank and to the third tank.

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