Process for treating pistachios

Abstract

A method for treating in-shell pistachios is disclosed, comprising the following steps: a. Wetting the pistachios with water, especially with a brine, b. Heating the moistened pistachios for pasteurization and / or roasting, In the method according to the invention, the pistachios are treated with ultrasound during wetting with water, in particular the brine, and / or subsequently thereto and / or the heating of the moistened pistachios comprises a step of heating the pistachios in a flat, preferably single-layered, spread-out bed by irradiation with short-wave infrared radiation with a wavelength of λ ≤ 1.4 µm, in particular with a wavelength λ of 1.2 µm ≤ λ ≤ 1.4 µm, and / or the heating comprises shock heating of the pistachios by means of hot air at a temperature of 300-600°C for a period of 10 to 60 seconds.

Description

The invention relates to a method for treating pistachia.Pistachia is known to be latently loaded with salmonella. The prevalences are between 0.5 and 3%, depending on origin, variety, harvesting methodology, and processing immediately after harvesting and before shipping.Pistachia is stone fruits whose core enclosed in a hard, wood-plated shell is consumed. When the tire is placed on the tree, the shell opens and releases a gap-like access to the core. Pistachia can be infected already on the tree by contact with germinated aerosols or with salmonella via other transmission paths. Due to their peritrical biting, salmonella are capable of active movement and therefore can penetrate the mature fruit once the shell on the tree has opened. Salmonella attack the core of the pistachie by adhering to the surface of the exposed cell structure and then migrating into the pores.Salmonella can cause severe infections in infants, frailty or elderly people, even fatal in particularly severe cases. Humans with weakened immune systems, but also healthy persons infecting themselves with salmonella, frequently suffer from severe fever hyperses, sometimes also bloody, diarrhea, nausea, vomiting and swelling abdominal pain. In rare cases, infection with salmonella may result in the pathogen entering the blood and causing more severe diseases such as arterial infections including aneurysms, endocarditis and arthritis.For this reason, infections with salmonella in Germany are subject to reports. Any disease, but also the suspected of Salmonellalose, must be reported by the attending physician to the responsible health office. If salmonella are found in foods within the scope of routine investigations, the laboratories are obligated to report these findings to the food authorities. The latter must then usually pull the goods out of the transport.Raw pistachie kernels are not particularly palatable. They are therefore usually roasted before packaging and before sale to consumers. Although pistachia can also be peeled first and then roasted, i.e. only roasting of the kernels can take place, often the fruits with the shell, i.e. the kernels located in the shell, are roasted together with the shell. This process is also referred to as inshell roasting, and the commercial product obtained thereupon is referred to here as inshell pistachie.Such inshell roasting is typically carried out by exposure to hot gases. Typical roasting parameters for the inshell roasting of pistachia with hot gases according to the prior art are a roasting time of 10 to 20 minutes and gas temperatures of around 140 to 180°C.For a long time, professional roasters have considered that the thermal energy introduced into the pistachia during such a toasting process is sufficient to reliably kill any salmonella present. This view appears to be initially comprehensible. This is because the technical literature specifies, as requirements for killing Salmonella, a process which is also called pasteurization, typically values of 70-72° C. over an exposure time of about ten minutes.However, it must first be clarified here that the required killing temperature of 70° C. has to be reached in the interior of the salmonella, precisely even in its cell nucleus, in order to ensure reliable and reproducible killing.As stated above, hot air roasting of InShell pistachia is typically carried out at significantly higher temperatures in order to form the desired roasted flavors and to obtain a crisper texture of the pistachia core, i.e. to alter the cell structure of the core accordingly. The fact that these massive temperature-related changes take place in the cell structure of the nuclei appeared to further confirm the assumption that salmonella colonization of pistachia cannot survive such a process live, at least not capable of reproduction. This perception is reinforced by the fact that experience has shown that the degree of roasting or the texture of pistachie kernels roasted in the shell is entirely uniform, which is a reason for a uniform action of the heat of the roasting energy on the entire fruit, at least on which the kernels are speaking.Pistachia is unique as roaster because although roasted in the tray, the tray is partially open. The degree of this opening can be very different, from almost closed, to breakage of the shell into two parts. Unlike pistachia, most nuts are roasted in the peeled state, i.e. as cores without a shell, for example hazelnut cores or cashew cores. Peanuts can be roasted as a whole, i.e. in the shell, and certain types of almonds can also be roasted.If nut kernels without shell are roasted, the killing of salmonella during a roasting process can be reproduced and thus validably represented, because the heat input into the exposed skin or, in the case of blanched nut kernels, into the exposed meat of the nut kernel is unproblematic. If whole nuts are roasted in the shell, with the shell intact and closed, it is to be assumed that salmonella cannot penetrate through the intact shell into the interior of the nut. In this case, the killing of salmonellas which are seated on the surface of the shell during a roasting process can likewise be reproduced and thus can be displayed in a validable manner.The situation is different for InShell pistachies. The problem with roasting pistachia in the shell is that the partially opened shell does not on the one hand represent a barrier for the germination of the core surface or skin surrounding the core, but the shell on the other hand also obstructs the heat transfer into the interior. Inside the opened pistachie, a hardly movable air cushion is formed, which exerts a heat-insulating effect. This is made more difficult by the fact that the roughness of the surface of core and shell brings about the formation of immovable boundary layers. These stationary air boundary layers have a thermally insulating effect.The pistachie typically has an elongated shape. The shell consists of two halves. The pistachie opens because the halves separate on a narrow side. On the opposite narrow sides, the two shell halves remain connected to one another, so that a type of biological hinge is formed. The farther a given point is located in the interior from the opened narrow side and the closer this point is in the direction of the closed narrow side, ideally along the center line in the longitudinal axis, the less probability is that an air exchange with the environment takes place at this point during the roasting process. Heat transfer does not take place in these regions, or takes place only slightly, by convection of heated air, but rather via heat conduction from the outside of the shell into the interior of the nut.The heat conduction into the interior of the pistachie, into the regions in which little or no heated air penetrates by convection processes, can be adversely affected. The core is usually loosely located in the opened shell and therefore necessarily has only a very small contact area with the shell. In unfavourable cases, this contact exists only pointwise at three points.In addition, the pistachie nucleus is surrounded by a skin. Because of the drying processes and the different expansion rate of skin and core, the planar connection of skin and core is at least partially released. In addition, the skin can tear, so that loose pieces of skin form, which are enclosed in the cavity between core and shell. It is to be assumed that in individual cases loose skin particles can wedge between the pistachia nucleus and the pistachia shell in such a way that in the worst case there is only punctiform contact at two or three points. This then has the consequence that the heat transfer resistance for heat conduction from the core or shell into the skin particle is very high at these points.For roasting InShell pistachia, grid belt roasters are used in the prior art, in which the fruits to be roasted pass through a roasting chamber on a grid belt. These lattice band harvesters are generally heated by combustion of natural gas or hydrogen in a burner, and are also operated individually with oil, in particular if gas is not available. The heating of the process air, which is directed onto the nuts in the cross-flow method, can take place directly through the burner or via heat exchangers. It is also to be expected that in the future the air with which the roast material is heated is heated with electrical resistance heaters. In this case, the infrared heat would act indirectly on the nuts via the carrier medium hot air.For roasting pistachies with heated gases in the grid belt roasters, the roast material is conveyed through the plant on the grid belt. The grid belt is designed on the one hand such that the fruits cannot fall through openings, but on the other hand also such that the flow is possible transversely to the horizontal running direction, usually in a vertical plane. This is thus a cross-flow method. The thickness of the layer on the mesh tape is between about 3 cm (corresponding to 3 to 4 layers of pistachia) and up to over 20 cm.Typically, the flow through the roaster is very large and very turbulent; air amounts of 10,000 to 100,000 cubic metres per hour are the rule. To promote the uniformity of roasting, mesh belt roasters can be divided into segments. The direction of flow through the roaster is rotated 180 degrees from section to section in such cases. In one segment, the heated air flows from top to bottom. In the following segment, the air flows in the opposite direction. This is intended to improve the transfer of heat from the heated air into the roaster. The roast material is thus considered with respect to its flow-through capability as a type of diode, that is to say as a mass which can be flowed through better in one direction in discrete regions than in the opposite direction. The reversal of the direction of flow is intended to compensate for this diode effect and to make roasting more homogeneous. In addition, there will be areas whose flow resistance is higher than the mean value of the flow resistance of the roaster layer. These points must be thought of as a throttle. There will also be regions that have lower flow resistance. The inventor assumes that the flow resistance of the roaster layer can be described by a Gaussian distribution of probability density. Furthermore, the inventor assumes that the flow through these regions with different flow resistance follows the laws of parallel circuit of resistances, that is to say that the flow rate per area is in an inversely reciprocal relationship to the flow resistance. This has the consequence that the regions with low flow resistance allow significantly more heated gases to pass at the expense of the regions with high flow resistance. In reality, the flow of hot air through the roaster is therefore much more non-uniform than is assumed according to the prior art. The combination of this technology with the addition of water or water vapor for the purpose of pasteurization is described, for example, in DE 10 2018 121 453 A1.Manufacturers and users estimate from the lattice belt mortars known from the prior art that they can be implemented very easily in mechanical construction and that they allow a high throughput. Lattice band shapers are particularly easily scalable in terms of their functional principle and in terms of their construction and can therefore be designed with very high throughput capacity.In industrial mass production, lattice band harvesters with capacities of up to 7,000 kilograms of InShell pistachia per hour are used. For a unit weight of about 1.2 grams per pistachie, this means that such a roaster roasts over 4 million pistachie per hour. Assuming now, conservatively estimated, a prevalence of 0.5% for the presence of salmonella in the roaster, this means that 20,000 contaminated pistachies are fed into such a roaster per hour. It follows from this that, with regard to killing salmonella, the roasting process must be understood as a safety device which is subjected to a hazardous event for an extremely long and an extremely often time. It follows that the process must run extremely uniformly and stably if the breakdown safety against the detected risk is to be ensured despite the high stress intensity. According to the inventors' perception, this is not exactly the case according to the prior art. The recalls of roasted pistachias due to contamination with salmonella confirm this opinion.Findings from salmonella in roasted pistachia have now occurred in routine sampling control a number of times to oppose the above-discussed acceptance of reproducible pasteurization by prior art roasting operations. Thus, for example, in the USA several calls have already occurred for pistachies which have been roasted in the dish and in which contamination with salmonella has been detected.In the inventors' eyes, the prior art approach and the considerations and assumptions made up to now do not take sufficient account, in particular, that certain Salmonella strains successfully react to thermal stress by being able to form protective proteins and transition into a resting state. The transition from salmonella to this more heat-resistant rest state can be promoted by the fact that they are not heated suddenly, i.e. as quickly as possible, but rather gradually. The slower the heating occurs, the more time is available to the salmonella to successfully transition to the quiescent state. Furthermore, it is not taken into account that salmonella in a dry environment can also survive temperatures of 90 degrees Celsius and more for longer periods of time. It is believed by the inventor that these lesser phenomena are a reason for the survival of salmonella in conventional hot airunners to be observed.The following considerations are added in the treatment of pistachia:A very large part of the pistachia is treated with brine before roasting in order to intensify the taste by adding salt. The water which has transported the salt load into the pistachie evaporates during the roasting process and the finely crystallized salt remains in the roast material. This is usually carried out on an industrial scale by means of machines known as coaters. These are rotary tube conveyors into which the brine is sprayed via a probe. The conveying movement of the rotary tube generates in the product both a linear movement component parallel to the axis of rotation of the rotary tube and a rotation of the product stream. This rotation leads to the formation of a product roll, since one can consider itself as a kind of permanent avalanche which is standing on the spot. The mixing effect of such rotary pipes can therefore be very good if the machine is long enough. In practice, the admixture of the brine is nevertheless not optimal according to experience. In a bag with 250 grams of pistachia, i.e. around with about 200 pistachia contents, there are usually at least two or three pistachias which taste less salty than would be expected. This fact is a clear indication that the brine process often runs less stably and reproducibly than would be desirable.Furthermore, it is believed that this addition of water or brine increases the thermal conductivity in the roast material during the subsequent roasting process and thus promotes the killing of salmonella. It is here anticipated that salmonella under optimum conditions may double in number on a given substrate within 20 minutes if sufficient free water is available. The addition of brine provides free water to a relevant extent. Relevant in this context is an addition of free water which exceeds 25% of the residual moisture present in the cores, which can be up to 6.5% according to the UNDECE standard (standard of the United Nations Economic Commission for Europe). The water activity is at an Aw value of around 0.65.Salmonella, upon the provision of free water, respond to spontaneously beginning to proliferate until the available free water is consumed. The optimum temperature for such an increase in Salmonellais between 35 and up to 43° C. In this case, an increase in Salmonellacan be strongly promoted in an unintentional manner, especially in the large-industry roasting of pistachia, by the action of waste heat of the actual roasting process. Since the multiplication does not occur until above a pH of 9, the addition of conventional amounts of salt does not prevent the multiplication of salmonella in pistachias as a result of the salt process.The multiplication of salmonella in the pistachia is also further promoted by the fact that an unheated intermediate bunker is usually installed at the inlet of a band toaster. The object of this intermediate hopper is to convert the concentrated product delivery of the rotary coater in the form of a dot into the linear delivery which is intended to ensure uniform feeding of the grid belt over its full width. Intermediate bunkers of this type, in particular non-heated ones, are problematic because the theoretical mean dwell time of the moistened pistachias in the bunker is already relevant in relation to the above-mentioned division duration of salmonella of 20 minutes, so that a spread of the salmonella load is strongly promoted. If it is observed that, due to short-circuit effects in a vertical plane above the outlet of the bunker, there are subsets whose dwell time is very short, it becomes clear that, in order to balance the flow balance, there must also be zones in the bunker in which subsets dwell for a significantly longer time, for example in the corners. This means that in these partial quantities passing through with a delay, the load with salmonella can increase abruptly.The risk of uncontrolled multiplication of salmonella in moistened pistachia is furthermore particularly acute in non-steady operating states of the roasting plant, in which the occupancy of the plant does not remain constant, but increases or decreases. These can be machine malfunctions in the roaster, which lead to moistened pistachies being located in the holding hopper for a significantly longer time than during regular operation, in which the occupancy remains constant and which is referred to here as the stationary state. However, planned interruptions in operation, such as a noon break, also lead to moistened pistachia lying for a longer time before they are roasted. Transitional processes such as the start-up of the annex after a standstill, for example on the next day after a weekend or an operation interruption, or the running of the plant out for a job change, can also lead to the dwell time of moistened pistachias before roasting significantly increasing compared to the average values of normal, dynamic operation.The relatively low frequency of salmonella findings in roasted pistachias compared to the amount produced is a strong indication that the survival of salmonella in the roasting process is associated with non-steady plant conditions or the transitions, since these have an influence only on a small fraction of the finished product.It is thus clearly understood that germination of the interior of a pistachie with salmonella cannot be reliably eliminated by conventional roasting methods. Salmonella, in particular, which have colonized skin particles which have detached from the core during or before the roasting process are protected there in individual cases from heat transfer by convection or heat conduction in such a way that they have a realistic chance of survival which is relevant for a possible germination.The addition of brine, too, is not an improvement in the safety of killing according to the inventors' opinion and contrary to the accepted state of the art, but rather creates a further problem, quite on the contrary. It is true that added water or salt brine can improve the heat conduction or the heat transfer. However, it is by no means possible to guarantee that the interior of a pistachie is completely wetted by the lake, i.e. the entire inner side of the shell, the entire skin, whether it is loosely keyed in the shell or resting against the core, and all other areas of the core that are exposed. The above mentioned non-uniformity of salt formation demonstrates this. The prior art overlooks that the evaporation energy absorbed by the added liquid during the roasting process is relevant with respect to the heat capacity of the shell and core of the pistachias. Thus, a highly effective evaporative cooling is unintentionally introduced into the process, which moreover has a non-uniform effect. The reproducibility of the heating is thus decisively disturbed and the chance of survival of a bacterial colonization is considerably increased.For reliable elimination of salmonella inShell pistachia, it could be considered to pre-arrange a separate process step before roasting pistachia, which permits reliable killing of salmonella by means of separate pasteurization. However, owing to the problem of the opened shell, pistachines cannot pasteurize sufficiently safely, at least not with a reasonable outlay, using processes known for pasteurizing nuts and nut products.The following basic methods are known for the separate pasteurization of nuts:It is known to heat nuts or nut cores inside a helical stainless steel tube conveyor through which electrical current flows. This is an electrical resistance heater. Such installations are manufactured, for example, by Revtech Process Systems. The plant is open at the inlet and outlet, so that the atmospheric pressure acts basically in the interior. A heat transfer from the heated tube conveyor into the nut treated in this way takes place by heat conduction, so that the problems outlined above with reference to the example of hot air shot can be transferred via the heat conduction conditions in the interior of the pistachie. The addition of water or water vapor in certain sections of the pipe fundamentally does not change anything. Here, the same considerations apply as were done in connection with the addition of brine. In the case of pistachies, it is additionally made more difficult that the contact surfaces between the shell and the tube wall are predominantly formed in punctiform fashion, and heat can be transferred in a correspondingly poor manner. These plants are very well suited for pasteurization of nut seeds, but not for pasteurization of pistachia.Also known are installations which use wet steam as medium for the heat transfer. In order to lower the boiling point of the wet steam and thus undesirable changes in the nuts, a reduced pressure is applied in some designs of these installations. The treatment chambers must therefore be designed pressure-tight in these cases, which makes these installations considerably more expensive. These plant concepts also offer the possibility of drawing vacuum alternately and then refilling the vacuum with wet steam. These long-wave pulsations of the chamber pressure can have a favourable influence on the penetration of the material to be treated. Pasteurization processes according to such processes usually take several hours, up to one day and longer for large chambers. Such machines are offered by Napasol and H2OExpress. It seems possible that such installations can kill salmonella with high certainty even in pistachies, in particular if the process time is greatly extended and the degree of evacuation is greatly increased. In addition, the number of interactions between evacuation and vapor deposition can naturally be increased. However, processes of this kind are too expensive for the large-industry pasteurization of InShell pistachia. This is made more difficult by the fact that InShell pistachias have a lower density compared to nut cores, so that the degree of utilization of the vacuum chamber is correspondingly low with regard to a mass throughput.Also known as prior art is the use of microwaves for pasteurization of food. However, in the industrial treatment of nuts, seeds and nut seeds, these are hardly used because of the high investment volume in relation to the processing capacity and the inherent radiation protection problems.The complete killing of a Salmonella colonization of a food is in most cases not possible without destroying it by excessive energy input or at least markedly reducing its genus value. According to the present state of the discussion, for reasons of pragmaticity, a destruction rate of 10Tc4, this is a reduction by the factor of 10,000, referred to colloquially as "log4", or 10Tc5, this is a reduction by the factor of 100,000, referred to colloquially as "log5", is considered sufficiently safe. In the USA, pasteurization of almond cores is legally prescribed with a certainty of log5. Pasteurization of pistachies is legally prescribed there with a certainty of log4. The American legislator, when making lower legal requirements for pistachies, accepts with these requirements the fact that pistachies should be pasteurized and that this is more difficult to realize than the pasteurization of nut kernels. An improvement in pasteurization compared with the prior art is thus fundamentally desirable.Based on the above assumed contamination of 20,000 Salmonella infected pistachia per hour in a conventional roaster, a reduction rate of log4 would theoretically mean that as many as 2 contaminated nuts would pass through the process live. This is a theoretical model calculation, to clarify the relationships. The inventor is aware that the prevalence, i.e. the rate of finding salmonella before or after a process step, theoretically does not suggest anything about the infectivity of salmonella colonization, because the concentration of contamination of salmonella in the food also plays a very large role with regard to the severity of the course of a salmonella infection. Healthy humans can survive infection with a small amount of salmonella without problems, in some cases even unnoticed. Older and diseased people are at risk to a substantially greater extent. Ideally, a decrease in the concentration of a given Salmonellacontiguous is more important than a decrease in the number of Salmonella nesters. On the other hand, foods contaminated with salmonella are generally used by German food authorities for traffic, regardless of the level of load.Both ethical and economic aspects, any improvement in pistachia pasteurization over the prior art is highly desirable.The present invention has therefore made its object to develop a reliable cost-effective method for the treatment, including roasting, of InShell pistachias in industrial mass production, which at any rate greatly reduces, at best even completely excludes, the survival rate of Salmonella. A further object of the invention is to provide a resilient method for validating the successful killing of salmonella which method identifies and permits the influence of randomness to be eliminated.This object is achieved first by a method for treating InShell pistachias with the features of claim 1. A further object is achieved by a method for checking the killing rate of a method for treating InShell pistachia for salmonella control as defined in claim 12. A possible development of such a method is specified in claim 13.According to the invention, a method for treating InShell pistachia, i.e. pistachia containing a core enclosed by a shell, first comprises generally the following steps: a. wetting the pistachia with water, wherein this can be conventional water or else water with a proportion of edible salt, i.e. a salt lake, b. heating the wetted pistachia for pasteurization and / or for a roasting process.According to the invention, one or more of the following steps are carried out: I. The pistachias are treated with water, in particular the brine, during wetting and / or subsequently with ultrasound. II. Heating the wetted pistachia comprises a step of heating the pistachia in a flat, preferably single-layer, bed by irradiation of short-wave infrared radiation having a wavelength of λ≤1.4 μm, in particular having a wavelength λ of 1.2 μm≤λ≤1.4 μm. III. The heating comprises a shock-like heating of the pistachines with hot air at a temperature of 300-600°C for a period of 10-60 seconds.The inventor has namely found in experiments that pistachies, which are also immersed in water or brine, enclose air bubbles between the shell and the core. The inventor has also been able to determine in experiments that the volume of enclosed air can be reduced in a relevant manner by exposure to ultrasound. The reduction in the volume of trapped air reduces the variance of subsequent process steps more constantly and makes them more manageable. This makes it possible to achieve complete wetting of the core of the pistachia and also of the surrounding shell and skin with the liquid, that is to say the pure water or the brine. This leads to an improved thermal conductivity due to the liquid. This effect then weighs and exceeds the evaporation cooling occurring during the later heating and evaporation of the liquid.The inventor has also found in further experiments that the comparatively bright shell of the pistachia can be penetrated by short-wave infrared radiation (IR radiation) with a wavelength λ≤1.4 μm, in particular a wavelength λ of 1.2 μm≤λ≤1.4 μm, which therefore penetrates as far as the core in order to be absorbed there by the core itself or by the core skin. In this way, the interior of the pistachie can be reliably heated, in particular if the pistachies in the effective field of corresponding IR radiation are distributed during the action time in such a way that they do not lie one above the other, so that no fruit is affected by shadowing.The inventor has finally also found in experiments that the pasteurization effect of a known infrared rotary tube machine is largely based on heat conduction within the material to be treated. Addition of water, which wets the surface of the material to be treated, promotes the heat conduction within the product roll. Furthermore, the inventor has found in experiments that the improvement in the heat conduction by addition of water from one piece to another piece in the product roll, in particular in the case of spherical products, is based on the fact that added water decisively increases the punctiform contact surface due to capillary effects, namely by several powers of ten. It is this enlargement of the contact surface, i.e. of the line cross section, which improves the heat conduction in a decisive manner. Commonly stated effects such as the influence of water vapor which forms when added water evaporates or the assumption that water addition critically reduces the heat transfer resistance are significantly less important than previously assumed if the material to be treated has a ball-like shape. As described above, water additions to pistachia do not cause a reproducible improvement in thermal conduction in the form of sufficient soaking of the entire fruit in its interior because of the uneven penetration into the fruit.With respect to the known infrared rotating tube methods, the IR radiation within the product roller does not act on the material to be treated because of the shading by the uppermost product layer. The inventor has found in experiments that, in practicable tube lengths and process durations, the probability of a single pistachie being present is not sufficiently great to allow sufficient radiation to penetrate through the shell into the interior of the fruit for safe killing of salmonella.In addition, the inventor has been able to find in experiments that, contrary to land-based expectation, pistachias can be briefly exposed to much hotter air without being damaged, in particular if this superheated air acts extremely turbulently and in a very strong air flow. Under suitable conditions, pistachines can be treated with air temperatures of 300 to 600°C for a period of 15 to 60 seconds. This type of treatment can be carried out in particular in a fluidized bed. Due to the high temperature difference of heat carrier to material to be treated and a distinct turbulence, the probability of finding being clearly reduced in this way can be successfully transferred to the more heat-resistant rest state.Only one of the proposed special treatment steps can now be undertaken. However, two or all of the steps may be combined with each other to further improve the reduction of a salmonella load. According to the inventors' opinion, it may be particularly advantageous, owing to the complexity of the bacterial colonization of pistachias, to achieve the killing of Salmonella contamination not by a single one of the measures proposed above, but to obtain a synergistic cooperation by using two or more of the approaches mentioned. This can help to ensure food security even better in the normally required range of log4or log5.Furthermore, the water, in particular the salt brine, can be preheated to a temperature above 60° C., preferably of 75-98° C., before application to the pistachie. This can be effected in particular partially or completely using waste heat from a downstream roasting process, for example by an air heat pump or a heat exchanger. If the liquid with which the pistachias are wetted is brought to such a temperature, it is already ensured at this point that a temperature level at which salmonella preferentially spread and proliferate is exceeded. In particular, first effects of killing germs can already be achieved.The pistachiae wetted with water, in particular with brine, are then advantageously kept at a temperature of more than 60° C., in particular more than 65° C., preferably 70-90° C., after wetting and until the subsequent heating.Such a warm maintenance of the pistachines wetted with brine or water to temperatures above 60° C., in particular 65° C., preferably between 70 and 90° C., in the subsequent treatment until heating, i.e. in particular in a mixing device, on transport devices and in the holding hopper, i.e. a maintenance of the temperature from the beginning of the addition of water or brine until in particular the beginning of the roasting process, has the result that even in the further treatment sequence, a temperature is not obtained which promotes the multiplication of salmonella. Here too, the heat required for keeping warm can be obtained at least partially or even completely using waste heat from a subsequent roasting process, for example by an air heat pump or a heat exchanger.The pistachia can furthermore be heated during wetting with short-wave IR radiation with a wavelength of λ≤1.4 μm and an energy input of preferably 0.1 to 0.2 KWh per kg of treated material, in particular to a temperature of above 60° C., in particular above 65° C., preferably 70-90° C. This can be effected, for example, in a rotary tube. This measure also serves to set an unfavorable medium for its multiplication for salmonella.The wetting of the pistachia with water or a brine can be effected in a conventional and known manner in a rotary tube. However, it can also advantageously be carried out by a dipping process, in particular in a flooded raw conveyor. If necessary, after such a dipping process, surplus lake must be separated off, which can be achieved, for example, on screen conveyors by shaking or also by means of centrifuges. An ultrasonic treatment advantageous according to this invention can be combined with both the known rotary tube process and the dipping process proposed here.The pistachia can be heated by means of the short-wave infrared radiation, in particular before a roasting process carried out by further heating, wherein the short-wave infrared radiation is then introduced preferably with an energy amount of 0.15-0.3 KWh / kg, preferably 0.185-0.22 KWh / kg, based on the mass of the pistachia. One or more turning operations may be carried out during the heating operation. Ideally, however, the pistachias are distributed in such a way that the layer thickness amounts to a pistachia height, so that no fruits lie one above the other and shade one another.In principle, roasting of the pistachia can also be carried out by means of infrared radiation. However, the pistachias can also be roasted by an additional or an alternative heat treatment in a lattice band roaster. If roasting of the pistachias is effected by introduction of hot air and in a griddle toaster, a possible shock-like heating of the pistachias by means of hot air at a temperature of 300-600° C. for a period of 10 to 60 seconds can advantageously take place during roasting in the griddle toaster.A shock-like heating of the pistachines for 10 to 60 seconds in a very hot 300-600°C exposure temperature can preferably be carried out with very turbulent air, in particular, but not exclusively, in a fluidized bed reactor.During roasting in a griddle toaster, the pistachines can be turned by turning elements introduced in the griddle toaster, which can be in particular plowshare-like turning elements of this type, in order to compensate for irregularities in the air flow. The ploughshare-like turning elements should be designed and arranged in such a way that 50% of the layer thickness remains undisturbed at the point of action, so that no break-through points for the hot air are created so that the preliminary pressure in the ventilation can be kept constant. The turning elements are advantageously staggered in number, penetration depth and arrangement in such a way that the pits are completely re-layered at least once in one pass.During the heating of the pistachia, steam, in particular in the form of saturated steam, superheated steam or superheated steam, can advantageously be introduced, for example via a steam injection into a process space.A further aspect of the invention is an improvement in the inoculation of reference goods with a bacterial suspension for challenge tests for validating the killing rate of a process.The validation of the killing rate of a process is generally carried out as follows for nuts and nut cores according to the prior art, by means of so-called challenge tests:Preparation / culture of a representative but non-pathogenic strain of Salmonella for inoculation, adjustment to achieve an appropriate concentration of germs about 10 6 Cfu / g of product. Then, inoculating a product sample, e.g. an amount of about 2 kg, with a seed suspension in a suitable seed concentration by wetting or dipping. The sample inoculated in this way is then passed through the process to be evaluated in such a way that it can subsequently be identified and separated unambiguously. The separated sample is examined for the extent of possible survival of germination.This procedure known from the prior art suffers from the same methodical weakness as brine salting with regard to a possible transfer to InShell pistachia, namely that the penetration of the liquid into the opened shell cannot take place in a reproducible manner, so that it cannot be ensured that the entire interior of the fruit has been inoculated in the product sample. This does not ensure that the challenge test simulates the worst-case scenario.In order to minimize this problem, the wetting of the interior of the pistachie can likewise be improved by applying ultrasound according to the invention. An alternative possibility of obtaining a very considerable improvement is achieved by immersing the pistachia in the seed solution in a suitable, pressure-resistant vessel and then applying reduced pressure to the interior of the vessel and bringing it back to normal pressure. For immersion in the seed solution, the pistachines can be suitably immersed by means of a grid. The pistachia is then held in particular below the surface of the liquid level. The vessel is sealed and, as stated, vacuum is applied. This causes the trapped air bubbles to expand and therefore swell out of the trays. The effect can be enhanced by repeating this treatment several times, optionally with a redistribution or intermixing of the pistachias between the individual treatment processes. Ideally, the vacuum container is made transparent, so that it can be observed whether bubbles are released or whether the inoculation has been successfully completed.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2018 121 453 A1

[0019]

Claims

A method for treating InShell pistachia, i.e. pistachia containing a core enclosed by a shell, comprising the following steps: a. wetting the pistachia with water, in particular with a salt brine, b. heating the wetted pistachia for pasteurization and / or for a roasting process, wherein the pistachia is treated with ultrasound during wetting with water, in particular the salt brine, and / or subsequently thereto, and / or wherein heating the wetted pistachia comprises a step of heating the pistachia in a flat, preferably single-layer, spread bed by irradiation of short-wave infrared radiation having a wavelength of λ ≤ 1.4 μm, In particular, with a wavelength λ of 1.2 μm≤λ≤1.4 μm, and / or wherein the heating comprises a shock-like heating of the pistachias by means of hot air with a temperature of 300-600° C. for a period of 10 to 60 seconds.Method according to claim 1, characterised in that the water, in particular the brine, is preheated to a temperature above 60°C, preferably from 75-98°C, before application to the pistachie.Method according to claim 2, characterised in that the pistachiae wetted with water, in particular with brine, are kept at a temperature of above 60°C, in particular above 65°C, preferably 70-90°C, after wetting and until the subsequent heating.Method according to one of the preceding claims, characterized in that the pistachines are heated during wetting with short-wave IR radiation having a wavelength of λ ≤ 1.4 μm and preferably with an energy input of 0.1 to 0.2 KWh per kg of treated material, in particular to a temperature of above 60°C, in particular above 65°C, preferably 70-90°C.Method according to one of the preceding claims, characterized in that the wetting of the pistachines with water, in particular brine, is effected by a dipping process, in particular in a flooded raw conveyor.Method according to claim 5, characterised in that after the dipping process, surplus brine is separated off, in particular by shaking on one or more screen conveyors or by centrifuging.Method according to one of the preceding claims, characterized in that the pistachies are heated by means of the short-wave infrared radiation before a roasting process carried out by further heating, wherein the short-wave infrared radiation is introduced with an energy amount of 0.15-0.3 KWh / kg, preferably 0.185-0.22 KWh / kg, based on the mass of the pistachies.Method according to claim 7, characterised in that the pistachies are turned during heating with the short-wave infrared radiation in one or more turning processes.Method according to one of the preceding claims, characterized in that roasting of the pistachies is effected by introduction of hot air and in a grid band toaster, a possible shock-like heating of the pistachies taking place by means of hot air at a temperature of 300-600°C for a period of time of 10 to 60 seconds during roasting in the grid band toaster.Method according to claim 9, characterised in that during roasting in the griddle toaster the pistachines are turned by turning elements introduced in the griddle toaster, in particular plowshare-like turning elements of this type, in order to compensate for irregularities in the air flow.Method according to one of the preceding claims, characterized in that steam, in particular in the form of saturated steam, superheated steam or superheated steam, is introduced during the heating of the pistachias.A method for monitoring the killing rate of a method for treating InShell pistachia, i.e. pistachia containing a core enclosed by a shell, for killing salmonella, in particular a method for treating InShell pistachia according to any one of the preceding claims, comprising the following steps: i. preparing and / or growing a representative but non-pathogenic strain of salmonella for inoculating a sample batch of InShell pistachia, ii. selecting an amount of the salmonella for achieving a suitable germ concentration of about 10 6 KbE / g in the sample batch and introducing it into a germ suspension, iii. inoculating the sample batch with a seed suspension in the appropriate seed concentration by wetting or dipping, iv. carrying out the method for treating InShell pistachias on the sample batch in such a way that the pistachias of the sample batch can be unambiguously identified and separated after the treatment has been carried out, v. examining the separated treated sample batch for a degree of possible surviving germination, characterized in that the pistachias inoculated with the seed suspension are subjected to an ultrasonic treatment and / or in that the pistachias inoculated with the seed suspension are dipped into the inoculating solution in a pressure-resistant vessel and are held below the surface of the liquid level and the vessel is subsequently sealed, wherein a reduced pressure is applied in the interior of the vessel and after a holding period the interior of the vessel is brought back to normal pressure.Process according to Claim 12, characterized in that the application of a reduced pressure and bringing to atmospheric pressure is carried out repeatedly in stages, optionally with a redistribution or intermixing of the pistachias between the treatment stages.