BACKGROUND

[0001] Water is one of the most important factors controlling the rate of deterioration of food. A reduction in water activity (A _w ) for ingredients and foods is often used to preserve food, stabilize raw materials and ingredients, and aid in the development of shelf-stable foods. Reduction of water activity in foods prevents the growth of vegetative microbial cells, germination of spores, and toxin production by molds and bacteria.

[0002] Foods and ingredients used in food products are often subjected to heating, freeze drying, spray-drying, and osmotic concentration methods to reduce food water activity to increase shelf-life and promote storage and transportation. These low water activity materials are often utilized by food manufacturers as an ingredient or component of a food product. Often, the low water activity food material is heated again, prior to consumption, or application to a food product, in meeting various processing and/or safety guidelines. If the low water activity food materials remain untreated prior to consumption or employment into food products, such low water activity food materials can eventually impose health risks to consumers, particularly if there is post pasteurization contamination· Low water activity ingredients such as ground nuts or powders such as spices, proteins, flours and dairy powders can have high microbial colony counts as well as aerobic spore- formers, anaerobic spore- formers, and S. aureus compared to the other food categories. In the past 25 years, pathogen outbreaks such as Salmonella, E. Coll etc. have impacted low-moisture ingredients and foods from black pepper to rice and toasted oats to nuts. Even though these food materials have been processed to reduce water content, low water activity food materials are not invulnerable to food safety issues because microbes can survive when they develop heat resistance and slowed metabolic rates.

[0003] A crucial step that is often omitted is the application of an additional heating step to the low water activity food material prior to incorporation to a food product which has the ability to control, reduce or kill potentially contaminated food-borne bacteria. Further, there is a lack of understanding and standardization in some heating time/temperature relationships that are required to ensure food product safety. In addition, food quality and sensorial attributes such as taste and texture are important to consumers. Thus, there is a need for a heating technology that will achieve the desired microbial control, reduction, or kill rates uniformly and in a reasonable amount of time, with minimal altering of the overall quality of the food.

[0004] Existing heating technologies for the pasteurization of low water activity food materials typically employ either hot water or steam. These technologies have several limitations including reliance on thermal conduction from the product surface (resulting in non- uniform heating), slow heating rates (especially in the product center), large floor space requirements, poor overall energy efficiency, generation of large amounts of waste-water and limitations on the product geometry (i.e., need to be thin or flat).

[0005] Dielectric heating, such as radio frequency dielectric (RFDH) heating applications have been very successful in the non-food industry, including paper, lumber and plastic. Although quite limited in terms of its application in the food industry as a whole, the consumer demand for ever-tastier, ever-cheaper, low or no-fat, chemical free and safe products have recently extended its application in the food processing. The present disclosure provides a unique process for meeting consumer demands while improving food safety through dielectric heating of low water activity (A _w ) food materials.

SUMMARY OF THE INVENTION

[0006] The present disclosure is directed to a unique means for processing low water activity (A _w ) food materials to reduce microbes during food processing. Dielectric heating, radio frequency dielectric heating (RFDH) heating, microwave, or other convectional heating such as direct or surface heating processes are utilized to treat low water activity food materials to improve the overall safety and quality of food products wherein low water activity food materials are applied to various edible food products without compromising consumer acceptable sensory characteristics and nutrient content.

[0007] In certain aspects, the low water activity (A _w ) materials are food powders, treated by radio frequency dielectric heating (RFDH). The food powders described herein include but are not limited to nonfat dry milk, skim milk powder, whole milk powders, whey and whey products, whey protein concentrates, milk protein concentrates, whey protein isolates, milk protein isolates, cheese powder, yogurt powders, and fat filled powders. Treatment of food powders by radio frequency dielectric heating (RFDH) uniformly reduce microbial counts in a reasonable amount of time with a minimum altering of the overall quality of the food powders. More specifically, the food powders are dairy powders.

[0008] In other aspects, the low water activity (A _w ) food materials are plant-based foods, such as tree nuts and peanuts. The tree nuts and peanuts may be shelled, or in a granular forni and treated by dielectric heating, such as radio frequency dielectric heating (RDFH) , microwave, or other convectional heating such as direct or surface heating processes. Alternatively, such tree nuts and peanuts are further reduced in particle size to a powder. After heat treatment, the low water activity food material in a powder form derived from dairy or plant sources are incorporated into a finished food product wherein the taste profile of food product is not negatively impacted by incorporation of the heat treated low water activity food material.

[0009] In an aspect, the low water activity food materials which are in granular or powder form are treated by dielectric heating, radio frequency dielectric heating (RFDH), microwave heating, and other convectional heating. Preferably, the low water food materials, such as dairy powders, peanuts or tree nuts are thermally treated by radio frequency dielectric heating. The food materials described herein are heated to a target temperature range of about 70°C to 105°C to control, reduce, or kill microbes. In still another aspect, the low water food materials treated by direct or surface heating treatments are heated to a target temperature of at least about 70°C. In alternative aspect, the low water food materials are treated by radio frequency dielectric heating, microwave, or other convectional heating such as direct or surface heating processes, and heated to a maximum temperature of 105°C.

[0010] In another aspect, the low water activity materials, are food powders, such as dairy powders, peanuts, and tree nuts which are held at desired temperature range of 70 to 105°C for at least 4 minutes to 400 minutes.

[0011] In an aspect, the thermal treatment process can hold a large volume of low water activity food material at a temperature of about 70°C to about 105°C, more specifically in temperature range of about 70°C to about 100°C, or from 70°C to 100°C, or from 70°C to 95 °C, or from 70°C to 90°C, or from 70°C to 85 °C, or from 70°C to 80°C, or from 70°C to 75 °C to provide maximum microbial reduction and best quality.

[0012] In another aspect, the low water activity food material has a moisture content of about 1 wt% to about 12 wt%, of about 2 wt% to about 8 wt%, and from about 3 wt% to about 5 wt% by weight of the low water activity food material.

[0013] In an alternative aspect, the low water activity food material is held for 4 minutes to about 400 minutes to provide a 1 to 35 log microbial reduction without compromising product quality, such as taste, appearance, color and odor attributes of the treated low water activity food material. [0014] In certain aspects, the low water activity food material (i.e., powder or granule) is thermally heated, held for a period of time, size reduced, cooled, stored, and incorporated into a confectionery product such as chocolate, caramel, nougat, etc.

[0015] In another aspect, the low water activity material is a dairy or plant based material including but not limited to flours, isolates, concentrates, etc. derived from soy, oat, wheat, rice, almond, or combinations thereof, as well as tree nuts and peanuts that are thermally treated using methods such as radio frequency dielectric heating, microwave heating, convectional (direct or indirect) heating and is incorporated into a coating composition which is applied to a food product or confectionery product.

[0016] In another aspect, the thermal treatment process involves powder handling, conditioning, heating, holding, size reduction, cooling and storage that controls, reduces, and/or eliminates microbial risk.

[0017] In a specific aspect, the heating system is a continuous/or batch process, wherein the process first conveys the food material on a network of belts and/or screw conveyors through a heating step that can include such as radio frequency dielectric heating, microwave heating, and/or other convection heating steps to reduce microbes then the food material is size reduced and cooled. Alternatively, the network of belts and/or screw conveyors may be utilized before or after heat treatment by radio frequency dielectric heating (RFDH), microwave, dielectric, or convection heating either direct or indirect. In another aspect, before or after heat treatment, the low water activity food materials may be size reduced and transported.

[0018] The foregoing has outlined broadly the features and technical advantages of the present disclosure in order that the detailed description that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific aspect disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the application as set forth in the appended claims. The novel features which are believed to be characteristic of the application, both as to its organization and method of operation, together with further objects and advantages will be better understood from the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] FIG. 1 is an exemplary diagram illustrating the process where the low water activity food material, such as a powder or granule, is delivered into a heating step (that includes radio frequency dielectric heating (RFDH), microwave heating, convection heating (direct/indirect) the powder moves by a continuous system into an insulated heating chamber where the powder is held at a specific temperature for a period of time for microbial reduction.

[0020] FIG. 2 is an exemplary diagram illustrating the process where the low water activity food material, such as a powder or granule, is delivered into a heating step (that radio frequency dielectric heating (RFDH), microwave heating, convection heating (direct/indirect); the powder is conveyed into a thermal screw chamber where the powder is held at a specific temperature for a period of time for microbial reduction.

[0021] FIG. 3 is an exemplary diagram illustrating the process where the low water activity food material, such as a powder or granule, is delivered into a heating step (that includes radio frequency dielectric heating (RFDH), microwave heating, convection heating (direct/indirect); the powder is then robotically transported.

[0022] FIG. 4 lists food categories, examples, and related water activities.

[0023] FIG. 5 illustrates sensory analysis of Nonfat Dry Milk (NFDM) over time.

[0024] FIG. 6 illustrates Sensory analysis of Whole Milk Powder (WMP) over time.

[0025] FIG. 7 illustrates Flavor Volatile Analysis of Whole Milk Powder (WMP) over time.

DETAILED DESCRIPTION

[0026] As noted above, there remains a need in the art for heating low water activity materials used in edible food products that controls, reduces or kills microbes without comprising the overall quality of the low water activity food materials, and/or a food product to which the low water activity food materials are applied. The presently disclosed subject matter addresses this need through the use of dielectric heating technologies, and more specifically, radio frequency dielectric heating (RFDH) that uniformly controls, reduces or eliminates microbes in low water activity materials in a reasonable amount of time with minimal impact to the overall quality attributes of the food materials.

[0027] The present disclosure relates to thermally treated low water activity food materials which are shelled, pulverized, or in a powder form, including but not limiting to dairy powders, tree nuts and peanuts. Alternatively, peanuts and tree nuts may be treated as discussed herein once the shells are removed, or alternatively, once they have been pulverized (i.e., granular or powder form). While bacteria do not grow well in low water activity food materials, they can survive, develop heat resistance, and remain in a dormant state. In order to appropriately treat the low water activity food materials such as, for example, dairy powders, in controlling, reducing, or eliminating microbial growth without compromising the sensorial attributes of the low water activity materials being treated, or the food products which they are admixed with, dielectric heating technologies are employed.

[0028] More particularly, the disclosure relates to the application of dielectric heating, also known as electronic heating, radio frequency heating, and high- frequency heating, which utilizes a radio frequency (RF) alternating electric field, or radio wave or microwave electromagnetic radiation to heat low water activity food materials. Exemplary low water activity food materials treated by dielectric heating include but are not limited to dairy powders, tree nuts, and peanuts. Using dielectric heating methods reduce microbial counts without negatively impacting the taste or quality characteristics of the treated low water activity food materials or the finished product to which the low water activity food materials are incorporated.

[0029] The process involves powder/granule handling, pre-conditioning, heating, holding, size reduction, cooling and storage that reduces and/or eliminates microbial risk while maintaining superior quality attributes that not only help with finished product quality and functional attributes but also downstream processing in various food applications. The process provides numerous benefits to the low water activity powders that are heat treated, such as microbial reduction or destruction, limiting opportunity for contamination during heat treatment, equal treatment of all the powder particles, and continuous processing. Additionally, the process enhances safety and quality characteristics to the powders which yields desired end product attributes such as a) enhanced flavor/color profile, b) increased shelf life and c) enhanced functional attributes that help with broad portfolio of end product applications leading to process simplification, inventory reduction and broadening of supply chain.

[0030] As the food and confectionery industries respond to increased awareness of safety, health and wellness concerns, finding ways to treat low water activity food materials prior to incorporation into finished food products is increasingly important. Using a heating step that includes radio frequency dielectric heating (RFDH), microwave heating, convection heating (direct/indirect) as a method to treat low water activity powders meets these desired safety issues while ensuring product quality and consumer acceptable sensory attributes. 1. Definitions

[0031] The terms used in this specification generally have their ordinary meanings in the art, within the context of this disclosed subject matter and in the specific context where each term is used. Certain terms are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner in describing the compositions and methods of the disclosed subject matter and how to make and use them.

[0032] As used herein, the use of the word “a” or “an” when used in conjunction with the term “comprising” in the claims and/or the specification may mean “one,” but it is also consistent with the meaning of “one or more,” “at least one,” and “one or more than one.” Still further, the terms “having,” “including,” “containing” and “comprising” are interchangeable and one of skill in the art is cognizant that these terms are open ended terms.

[0033] The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within 3 or more than 3 standard deviations, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value.

[0034] As used herein, “food product,” “edible food product” or “food product composition” includes ingestible products including but not limited to human foods, animal or pet foods, pharmaceutical products, and consumer products.

[0035] As used herein, the term “confectionery product” refers to a sweet or dessert food product. Confectionery products with surfaces suitable for the printing of an ink formulation can include, but are not limited to, candies (hard and soft), compressed mints, chewing gums, gelatins, chocolates, fudge, fondant, liquorice, taffy, and combinations thereof.

[0036] As used herein, the term “snack food” or “snack food product” refers to a sweet or savory food product, such as fruit snacks, chips/crisps, extruded snacks, tortilla/corn chips, popcorn, pretzels, nuts, granola/muesli bars, breakfast bars, energy bars, fruit bars, other snack bars, and combinations thereof.

[0037] As used herein, the term “food materials” refers to edible food materials derived from the vegetable kingdom and those derived from the animal kingdom. In the vegetable kingdom, food materials may be derived from different parts of many plants (leaf, fruit, root, nut, etc.), and second, substances manufactured from plants. Manufactured vegetable food materials include flour, meals, breakfast cereals, starch, sugar, molasses and syrups. Food materials from the animal kingdom gives the flesh of animals, fish and shell fish, and substances derived from animals, like eggs, milk, and the milk products, cream, butter, and cheese. For purposes of the present disclosure, the food materials are derived from plants or sources of dairy.

[0038] As used herein, “tree nuts” include, but are not limited to, almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, shea nuts and walnuts.

[0039] As used herein, “peanut” is a legume, and also known as a groundnut, goober, or monkey nut.

[0040] For the purposes of the present disclosure, the tree nuts and peanuts contemplated herein are shelled. A shelled nut is a nut that has had the shell removed.

[0041] As used herein, the term “granular” or “granule” means a material that is a conglomeration of discrete solid, macroscopic particles characterized by a loss of energy whenever the particles interact. Some examples of granular food materials are nuts, rice, coffee and com flakes.

[0042] As used herein, the term “pulverize” or “pulverization” refers to crushing, beating, or grinding of the food materials, such as nuts, tree nuts, and the like, as described herein and reducing them to small particles.

[0043] Powders are a special class of granular material due to their small particle size, which makes them more cohesive and more easily suspended in a gas. As used herein, the term “powder” refers to dry, bulk solid composed of a large number of very fine particles that may flow freely when shaken or tilted. In particular, powder refer to those granular materials that have the finer grain sizes, and that therefore have a greater tendency to form clumps when flowing.

[0044] As used herein, “dairy powders” include but are not limited to whole milk powders, non-fat dairy powders, nonfat dry milk, skim milk powder, whole milk powders, whey and whey products, whey protein concentrates, milk protein concentrates, whey protein isolates, milk protein isolates, lactose, fat filled dairy powders, cheese powders and yogurt powders.

[0045] As used herein, “water activity” or “A _w ” refers to the partial vapor pressure of water in a substance divided by the standard state partial vapor pressure of water. Water activity (A _w ) is expressed on a scale of 0 to 1 where 1 is for pure water. In the field of food science, the standard state is most often defined as the partial vapor pressure of pure water at the same temperature.

[0046] As used herein, “low water activity” or “low a _w ” refers to when the water activity (A _w ) is expressed as less than 0.85 on a scale of 0 to 1. Dried or low -moisture foods do not contain more than 25% moisture. For the purpose of the present disclosure low water activity materials are in a range of 0.1 to 0.85.

[0047] As used herein, moisture content (MC) refers to moisture content that is the quantity of water contained in a food material. The moisture content of the food materials described herein have a moisture content of about 1 wt% to about 6 wt%, of about 2 wt% to about 5 wt%, and from about 3 wt% to about 4 wt% by weight of the low water activity food material.

[0048] As used herein, the term “radio frequency dielectric heating” generally means heating using one of approved frequency of 13.56 MHz, 27.12MHz and/or 40.12 MHz.

[0049] As used herein, the term “microwave frequency” generally means heating using of an approved frequency of 915 and 2450 MHz.

[0050] The megahertz, abbreviated MHz, is a unit of alternating current (AC) or electromagnetic (EM) wave frequency equal to one million hertz (1,000,000 Hz).

[0051] As used herein, the term “dielectric” generally means an electrical insulator that can be polarized by an applied electric field.

[0052] As used herein, the term “conventional direct/indirect” generally means heating using combustion a fossil fuel (coal, oil, or gas) or electricity to generate heat which is then distributed into the space to be heated either directly in contact with food (using steam, air, modified air such as carbon dioxide, nitrogen etc.), or via indirect surface contact.

[0053] As used herein, the term “pasteurization” or “pasteurization” is a process in which water and certain packaged and non-packaged foods are treated with mild heat, usually to less than 100 °C, to eliminate pathogens and extend shelf life.

[0054] As used herein, the term “microbial log reduction” refers to a reduction of a microbial load on a log scale.

[0055] As used herein, the “dehumidified filtered air” refers to air for use during heat treatment processing which is filtered to remove contaminants or impurities, preferably F7/EU7 filtered air with 80% efficiency for particle 1 micron or greater and moisture level less than 7g/liter of air. For purposes of the present disclosure, the dehumidified filtered air has a dew point range of the -5C to -15C lower than the processing temperature. [0056] As used herein, the term “large volume” refers to any quantity greater than 100/kilograms processed per hour.

[0057] As used herein, the term “weight percent” or “wt%” is meant to refer to the quantity by weight of a component in a material (e.g., a spray dried powder) as a percentage of the total wet weight of the material (i.e., food product).

2. Food Materials

[0058] Food safety, is a global concern with the developing countries being the worst affected. In recent years, a number of incidences relating to outbreaks caused by the presence of food-borne pathogens in low water activity foods have increased. Microbes are a major cause of concern in low water activity (A _w ) food materials.

[0059] Low water activity food materials while considered safe, can be contaminated with pathogens during food processing in making food products, especially post pasteurization environmental contamination. Many of these food products do not undergo further microbial intervention/thermal treatment while being either used by consumers or processed in factories before being consumed by consumers. Use of contaminated low water activity food materials in food products can lead to health risks for consumers, costly recalls and negative impact to brand image.

[0060] Low water activity powders such as spices, proteins, sweeteners, flours, isolates, concentrates, etc., can be used as an ingredient in a variety of food products both by consumers and food companies such as nutrition bars, drink mixes, snack foods, confectionery, and baked products. Additionally, dairy powders have many uses in the food and beverage industry with large percentage of dairy powders utilized in ready to consume (eat/drink) food products that include but not limited to confectionery products, drink mixes, seasonings, health and nutrition products such as bars and beverages. Many low water activity food materials and food products where dairy powders are used do not undergo any kind of microbial intervention such as baking or cooking. Even in products such as crackers and chips, seasonings are added after baking/frying steps and contaminated seasoning can lead to contaminated finished product. Post pasteurization contamination during production of dairy powders and subsequent incorporation into a food product can lead to contaminated food products that may carry risk to a consumer’ s health.

[0061] Powders can be processed from a variety of raw materials. Other low water activity food materials include other powder food materials including spices and plant derived materials such as those sourced soy, wheat, oat, rice, and almonds. The disclosure herein utilizes several examples associated with low water activity (A _w ) powders, including, but not limited to, dairy powders.

[0062] In an aspect, the low water activity food material has a moisture content of about 1 wt% to about 12 wt%, of about 2 wt% to about 8 wt%, and from about 3 wt% to about 5 wt% by weight of the low water activity food material.

[0063] In another aspect, the food materials are derived from sources of dairy.

[0064] Dairy powders are produced by spray drying of milk, whey, whey derivatives or milk and whey protein concentrates/ isolates to produce nonfat dry milk, skim milk powder, whole milk powders, whey and whey products, whey protein concentrates, milk protein concentrates, whey protein isolates, milk protein isolates, lactose, fat filled dairy powders, cheese powders and yogurt powders etc.

[0065] In an alternative aspect, the food materials are derived from sources of plant. Other low water activity (A _w ) non-powder ingredients may be used, including but not limiting to tree nuts, peanuts, and seeds. Often, these plant sourced food materials are at a minimum shelled to leave a whole nut or seed, pulverized into granules or further pulverized, forming a powder.

[0066] In an alternative aspect, the methods and products disclosed herein may comprise tree nuts, including but not limiting almonds, Brazil nuts, cashews, chestnuts, filberts/hazelnuts, macadamia nuts, pecans, pistachios, shea nuts and walnuts. Such tree nuts may be shelled, or are often pulverized, and are in a granular form. Alternatively, the tree nuts may be further ground into powders. In yet another aspect, peanuts are employed, and may be treated in shelled, granular or powder form.

[0067] In another aspect, spray dried cacao pulp may be also pasteurized by radio frequency dielectric heating (RFDH) or microwave heating methods. The spray dried cacao pulp treated by radio frequency dielectric heating (RFDH) is incorporated into a confectionery product, such as a chocolate or caramel.

[0068] In an alternative aspect, the low water activity materials including but not limited to peanuts, tree nuts, dairy powders and cocoa pulp are treated by radio frequency dielectric heating and incorporated into a confectionery product. Confectionery products include hard candies, chewy candies, coated chewy center candies, tableted candies, chocolates, nougats, caramels, dragees, confectionery pastes, gums, chewing gums and the like. The dairy powders treated by radio frequency dielectric heating are incorporated into a confectionery such as a chocolate or ice cream. [0069] Further, the low water activity food materials treated by radio frequency dielectric heating or microwave heating, are incorporated into a snack food product, including but limited to savory or sweet snacks, such as fruit snacks, chips/crisps, extruded snacks, tortilla/com chips, popcorn, pretzels, nuts, granola/muesli bars, breakfast bars, energy bars, fruit bars, other snack bars, and combinations thereof. Still further, the low water activity food material may be admixed with a pet food or treat. Still further the low water activity food material incorporated to coating, which is applied to a food product such as a confectionery product, snack food product, and a pet food product.

[0070] By treating the low water activity materials by radio frequency dielectric heating or microwave heating, the low water activity food materials, including granules and powders, will achieve the desired microbial control, reduction, or kill rates.

[0071] uniformly and in a reasonable amount of time, without negatively impacting the overall sensory profile of the low water activity food materials or the food product to which they are incorporated or admixed.

3. Radio Frequency Dielectric Heating (RFDH) and Microwave Heating

[0072] Dielectric heating, such as radio frequency dielectric heating (RFDH) and microwave heating are promising technologies for food applications because of the associated rapid and uniform heat distribution, large penetration depth and lower energy consumption. Other convectional heating methods such as direct or surface heating processes may also be employed, alone, or in combination with the RFDH or microwave heating technologies. In general, the heating methods discussed herein have been successfully applied for drying, baking and thawing of frozen meat and in meat processing but, use of these dielectric heating methodologies in continuous pasteurization and sterilization of food materials is rather limited.

[0073] When heating a food material using RFDH or microwave heating, heat is generated within the product due to molecular friction resulting from oscillating molecules and ions caused by the applied alternating electric field. Unfortunately, when using these heating technologies, there remains a lack of understanding and standardization in heating time/temperature relationships that are required to ensure food product safety, without negatively impacting taste. In addition, food quality or taste/texture issues are important to consumers. Thus, there is a need for a heating technology that will achieve the desired microbial control, reduction or kill rates uniformly over the low water activity food material in a reasonable amount of time with a minimum altering of the overall quality of the food.

[0074] In an aspect, the low water activity food materials which are in granules or pulverized into powders are treated by dielectric, radio frequency dielectric heating (RFDH), microwave heating and other convectional heating are heated to a target temperature range. The low water activity granules or powders treated by radio frequency dielectric heating (RFDH), are exposed to a frequency of 13.56 MHz, 27.12MHz and/or 40.12 MHz. If the low water activity granules or powders are treated by microwave heating, the granules or powders are exposed to a frequency of 915MHz and 2450 MHz.

[0075] In still another aspect, the low water food materials treated by dielectric, radio frequency dielectric heating (RFDH), microwave heating and other convectional heating such as direct or surface heating treatments are heated to a target temperature of at least about 70°C. In alternative aspect, the low water food materials are treated by radio frequency dielectric heating, microwave, or other convectional heating such as direct or surface heating processes, and heated to a maximum temperature of 105°C.

[0076] Still further, the low water activity food material is heated from about 70°C to 105°C, or from about 70°C to 100°C, or from about 70°C to 95°C, or from about 70°C to 90°C, or from about 70°C to 85°C, or from about 70°C to 80°C, or from about 70°C to 75°C.

[0077] In another aspect, the low water activity material is held at desired temperature range of 70 to 105°C for at least 4 minutes to 400 minutes or from 4 minutes to 300 minutes, or from 4 minutes to 200 minutes, or from 4 minutes to 100 minutes, or from 4 minutes to 90 minutes, or from 4 minutes to 80 minutes, or from 4 minutes to 70 minutes, or from 4 minutes to 60 minutes, or from 4 minutes to 50 minutes, or from 4 minutes to 40 minutes, or from 4 minutes to 30 minutes, or from 4 minutes to 20 minutes, or from 4 minutes to 10 minutes to deliver targeted microbial reduction.

[0078] The process of the present disclosure involves handling, conditioning, heating, holding, size reduction, cooling and storage that reduces and/or eliminates microbial risk while maintaining superior quality attributes that not only help with finished product quality and functional attributes but also downstream processing in various food applications. The process provides numerous benefits to the powders and granules that are heat treated, such as microbial reduction or destruction in a low water activity environment, limited opportunity for contamination during heat treatment, equal treatment of all the powder particles, and continuous processing. Additionally, the process provides safety and quality characteristics to the powders which yields desired end product attributes such as a) enhanced flavor/color profile, b) increased shelf life and c) enhanced functional attributes that help with broad portfolio of end product applications leading to process simplification, inventory reduction and broadening of supply chain.

[0079] One of the challenges when using radio frequency dielectric heating (RFDH) heating is non-uniform heating in pasteurization of low water activity food materials. The effect of different electrode gaps, moisture content (MC), bulk density and surrounding materials, impacts heating consistency in low water activity materials.

[0080] The dielectric and thermal properties of the low water activity food materials can be tested for the effects of moisture content (MC), temperature (°C), and time (min). Changes in moisture content, water activity (A _w ), textural changes and color in the sample after thermal treatment can also be measured to evaluate treatment effect on food quality.

[0081] In an aspect, the dielectric frequency employed to heat low water activity food materials is from approved frequency of 13.56 Mhz, 27.12Mhz, 40.12 Mhz, 915 Mhz and 2450 Mhz electromagnetic field heating without compromising quality and sensory attributes of the low water activity food materials. The dielectric heating uniformity and temperature profiles of the low water activity food materials as exposed to dielectric heating were obtained with an infrared camera and a data logger connected to a fiber optic sensor.

[0082] In an aspect of the present disclosure, the radio frequency dielectric heating or microwave heating process of the present disclosure is a continuous process. A stream of a powdered dairy product can be introduced into a sanitary environment. For example, the sanitary environment can be a conveyance network of belts and screw conveyors. The stream of powdered milk product is conveyed to a temperature control device to, for example, equilibrate the temperature. The temperature control device can standardize the temperature at the beginning of the process. Also, temperature control can occur at a particle size reduction step and/or just after conveyance through a microbial reduction device.

[0083] As shown in FIG. 2, the process includes where the low water activity material, such as a powder or granule is delivered into a radio frequency (RF) exchanger; the powder is conveyed into a thermal screw chamber where the powder is held at a specific temperature for a period of time for microbial reduction. In another aspect, FIG. 3 shows a process where a low water activity material, such as a powder or granule is delivered into a radio frequency (RF) exchanger; the powder is conveyed into a thermal screw chamber where the powder is held at a specific temperature for a period of time for microbial reduction. 3. Holding Step

[0084] After heat treatment through radio frequency dielectric heating or microwave heating, the low water activity food materials, including but not limited to dairy powders, spray dried cacao pulp, and peanuts and/or tree nuts which are shelled, in granular or powder form are held for at least about 4 minutes to about 400 minutes wherein the process provides a microbial log reduction from about 1 log to about 35 log, from about 2 log to about 25 log, from about 3 log to about 15 log, or about 4 log to about 5 log. In another aspect, the low water activity food materials are held for a period to achieve a microbial log reduction of about 5 log. Alternatively, the low water activity food materials are held for a period to achieve a microbial log reduction of about 7 log.

[0085] In order to achieve the desired microbial log reduction, the low water activity food materials treated by radio frequency dielectric heating or microwave heating are held at desired temperature range of 70 to 105°C for at least 4 minutes to 400 minutes or from 4 minutes to 300 minutes, or from 4 minutes to 200 minutes, or from 4 minutes to 100 minutes, or from 4 minutes to 90 minutes, or from 4 minutes to 80 minutes, or from 4 minutes to 70 minutes, or from 4 minutes to 60 minutes, or from 4 minutes to 50 minutes, or from 4 minutes to 40 minutes, or from 4 minutes to 30 minutes, or from 4 minutes to 20 minutes, or from 4 minutes to 10 minutes to deliver targeted microbial reduction.

[0086] After heat treatment, the stream of low water activity materials is then conveyed to the microbial reduction device and held for at least about 4 minutes to about 400 minutes to ensure appropriate microbial levels without substantially denaturing and/or substantially affecting the functionality of the low water activity materials. The time and the temperature of the microbial reduction device are at least partially determined based on the type of low water activity materials treated (i.e., powder or granule). The product is subsequently size reduced. In aspect of the present disclosure the low water activity food materials are size reduced to about 80pm to about 25,000pm. For example, as shown in Figure 2, the process where the powder is delivered into a thermal treatment process; the powder is conveyed into a thermal screw chamber where the powder is held at a specific temperature for a period of time for microbial reduction.

[0087] Frequency level, temperature and properties of food, such as viscosity, water content and chemical composition affect the dielectric properties and thus the radio frequency and microwave heating of foods. Therefore, these parameters should be considered when designing a radio frequency or microwave heating system for flow water activity food materials. [0088] In another aspect, after size reduction, the low water activity food materials are conveyed via the duct network to downstream processes and storage via chilled forced air. Such cooling can minimize condensation formation throughout the system. In certain aspects, the low water activity food materials are cooled to about 10°C to about 50°C, to about 20C to about 40°C, and to about 25°C to about 35°C. In an alternative aspect, the low water activity food materials are cooled to less than 60°C.

[0089] In a certain aspect, after the low water activity materials are cooled, the low water activity food materials can be prepared for consumer packaging, bulk packaging, bulk vehicular transport via a holding tank, and/or conveyance to secondary production facilities.

[0090] In an aspect, dairy powders can be packaged in quantities such as 25 kilogram bags to 1000 kilogram bags or the like. In other aspects, the powdered milk product is not packaged. For example, the process described herein can include a conduit or conveyance network to provide a flow channel for a powdered milk product stream to a secondary processing or food manufacturing facility. In still other aspects, the size reduced product can be transported in bulk. For example, the product stream can be conveyed into a freight shipping container or vessel.

4. Sensory Attributes

[0091] By using heat treatments such as radio frequency, dielectric, microwave, or direct/indirect convectional heating processes, the low water activity food materials including those in powder form, have enhanced quality and sensory attributes. As detailed below, milk powders exposed to radio frequency heating are less prone to oxidation and experience improved shelf life, thereby improving sensory attributes, in particular, those relating to cooked dairy flavors.

Shelf Life

[0092] Figure 5

[0093] Sensory analysis of Nonfat Dry Milk (NFDM) over time. At time=0 NFDM was (a) heated to 95°C by radio frequency heating and held for 200min at 95°C in a lab controlled temperature chamber or (b) untreated to serve as a control. After treatments sensory analysis was performed by a trained panel on a monthly basis for 3 months.

[0094] Figure 6

[0095] Sensory analysis of Whole Milk Powder (WMP) over time. At time=0 WMP was (a) heated to 95°C by radio frequency heating and held for 200min at 95°C in a lab controlled temperature chamber or (b) untreated to serve as a control. After treatments sensory analysis was performed by a trained panel on a monthly basis for 3 months.

[0096] Figure 7

[0097] Flavor Volatile Analysis of Whole Milk Powder (WMP) over time. At time=0 WMP was (a) heated to 95°C by radio frequency heating and held for 200min at 95°C in a lab controlled temperature chamber or (b) untreated to serve as a control. After treatments flavor volatile analysis by GC-MS was performed on a monthly basis for 3 months.

Sensory Descriptive analysis

[0098] Sensory descriptive analysis was performed on whole milk powder and nonfat dry milk. Samples of each powder type were received from a milk powder supplier in the United States in their unopened, commercial package and within the manufacturer’s stated shelf life. A subsample that received no further treatment was deemed as a ‘control’. A subsample that is deemed as ‘thermally treated’ was tempered to ambient temperature (~18°C), thermally treated with RF heating at 95°C and held for 200min, cooled, and packaged in foil lined bags until analysis. Sensory analysis was performed by rehydrating to 10 % solids not fat (w/w) in deionized water for sensory testing. Preparations were conducted with the overhead lights off to prevent light-induced off-flavor formation. Products were dispensed into lidded souffle cups with 3-digit codes and evaluated at 21C. Skim Milk Powder (SMP) and Whole Milk Powder (WMP) were evaluated in duplicate by 6 sensory trained panelists using an established sensory language for milk powders (Lloyd et al., 2009).

[0099] Sensory descriptive analysis of finished product (e.g. chocolate) samples was performed by trained sensory panel on a 15 point scale. Products are coded with 3-digit codes and evaluated at room temperature. Chocolate sample were evaluated by 10 to 11 trained panelists, 1 replicate, 19 flavor/taste & 11 texture attributes (15 point scale).

EXAMPLES

[0100] In certain aspects of the present disclosure, the thermally treated low water activity food materials, such as dairy powder, including but not limited to non-fat and whole milk dairy powders, which is added to an edible food product in an amount effective to enhance the dairy, cooked milk and/or caramel sensory attributes, without increasing bitter taste, oxidation, or negative off-tastes. [0101] The concentration of the low water activity food materials admixed with a food product to modulate or enhance a sensory attribute of the food product or food composition can vary dependent on variables, such as, the specific type of composition, what compounds are already present in the product and the concentrations thereof, and the enhancer effect of the low water activity food materials employed.

[0102] In some aspects, radio frequency or microwave treated dairy powders are admixed into a confectionery composition, such as, for example, chocolates, caramels, and nougats to enhance the dairy, cooked milk and/or caramel sensory attribute, without increasing bitter or off-tastes to the confectionery composition.

[0103] The presently disclosed subject matter will be better understood by reference to the following Examples, which are provided as exemplary of the invention, and not by way of limitation. i. Example A

[0104] Nonfat dry milk (NFDM) at 3.5% moisture and 18°C was heat treated with radio frequency heating to 95°C and held for 200min. First, 6. libs of NFDM was weighed and evenly dispersed into a tray assembly consisting of a 12in x 12in Teflon frame, a trough shaped polyester belt in the frame acting as a carrier, and a disposable paper wipe all as a liner. The entire sample and assembly was lightly tapped to achieve a consistent sample height of 3.75in with care to fill any voids. The sample was transferred into an RFDH oven where an electromagnetic field was applied at 40MHz. Power was applied and controlled by regulating the electrode plate current limits between 0.95 to 0.80 amps and adjusting the speed at which the samples passed between the electrodes (215mm/min belt speed). The RFDH oven was maintained with 95°C air to prevent any surface cooling. Product and cabin temperatures were monitored using fiber optic temperature probes throughout the heat induction process. Upon reaching the target temperature in 17min, the temperature of the sample was confirmed with a hand-held thermocouple. Upon reaching the target temperature, the sample was immediately transferred to lab climate controlled chamber with a set point of 99°C to hold the sample for 200min at 95 °C. Temperatures of the chamber and the sample were monitored with temperature probes and automated data logger. At the end of the 200min the product was cooled to ambient temperature by breaking up any clumps and occasional mixing at ambient conditions. ii. Example B

[0105] Whole Milk Powder (WMP) at 2.6% moisture and 18°C was heat treated with radio frequency heating to 95°C and held for 200min. First, 3.91bs of WMP was weighed and evenly dispersed into a tray assembly consisting of a 12in x 12in Teflon frame, a trough shaped polyester belt in the frame acting as a carrier, and a disposable paper wipe all as a liner. The entire sample and assembly was lightly tapped to achieve a consistent sample height of 3.75in with care to fill any voids. The sample was transferred into an RF oven where an electromagnetic field was applied at 40MHz. Power was applied and controlled by regulating the electrode plate current limits between 0.95 to 0.80 amps and adjusting the speed at which the samples passed between the electrodes (211mm/min belt speed). The RFDH oven was maintained with 95 °C air to prevent any surface cooling. Product and cabin temperatures were monitored using fiber optic temperature probes throughout the heat induction process. Upon reaching the target temperature in 19min, the temperature of the sample was confirmed with a hand-held thermocouple. Upon reaching the target temperature, the sample was immediately transferred to lab climate controlled chamber with a set point of 99°C to hold the sample for 200min at 95 °C. Temperatures of the chamber and the sample were monitored with temperature probes and automated data logger. At the end of the 200min the product was cooled to ambient temperature by breaking up any clumps and occasional mixing at ambient conditions.

[0106] Sensory analysis of the whole milk powder samples, heat-treated and non-heat treated (control), was performed 1, 2, and 3 months after the treatment date by a trained sensory panel on a 15 pt. scale. In the heat treated sample the panelists detected the development of heated/graham cracker notes and an increase in astringency relative to control at each of the respective time points. The panelists also noted reduction in caramelized notes in the heat treated samples during the first 2 monthly time points. Of note unlike the controls at months 2 and 3, the heat treated samples did not develop any painty notes associated with lipid oxidation.

[0107] As a follow up to the sensory analysis analytical flavor volatile analysis was performed by (gas chromatography mass spectrometry (GC-MS)) with solid phase micro extraction (SPME). The analysis was able to quantitate the signature aldehydes (pentanal, hexanal, heptanal) associated with oxidation and specifically painty flavor with hexanal. The control samples did have greater levels of hexanal than the heat treated samples at each monthly time point which corroborates with the sensory analysis not detecting painty in the heat treated samples. The mechanism behind this unexpected finding is not completely known. Not to be bound by theory, but the generation of reactive sulfhydryl groups acting as an oxidative sink as a result of the heat treatment has been described by Stapelfeldt et al. 1997. It was observed that higher heat treated fluid milk used to make a whole milk powder was slower to develop oxidation defects and thus had a longer shelf life. The higher heat treated fluid milk had resulting higher levels of free sulfhydryl groups in the milk powders and was slower to oxidize than those powders that had lower levels of free sulfhydryl groups. The levels of the free sulfhydryl groups naturally dissipated over milk powder shelf life presumably due to oxidation where then lipid oxidation defects became noticeable. It is surprising that a similar and beneficial effect could be imparted at the powder state vs fluid state.

[0108] The flavor volatile analysis also was able to measure an increase in compounds associated with cooked/ heated notes in the heat treated samples. The compounds include benzaldehyde, 2-pentanone, 2-nonanone and most significantly 2-heptanone. These compounds could have positive flavor contributions to milk powders when used in confectionery applications like caramel and chocolate where cooked notes are desired. iii. Example C

[0109] Whole Milk Powder (WMP) at 20°C was heat treated with microwave heating to a target of 95°C. First, 12 - 6in x 6in plastic containers each holding 1.31bs of WMP were weighed for accuracy. All samples were lightly tapped to achieve a consistent sample height with care to fill any voids. The sample was transferred into a continuous microwave oven where an electromagnetic field was applied at 950MHz. Power was applied and controlled by 8 microwave applicators each set to 0.25kW, for a total of 2.0kW from all 8 applicators. Residence time was achieved by adjusting the speed at which the samples passed between the microwave guides (150mm/min belt speed). The microwave oven was maintained with 95C air to prevent any surface cooling. Oven temperatures were monitored using IR probes and product temperatures were measured upon exit of the tunnel. The target residence time was 20min, the temperature of the sample was mapped with a hand-held thermocouples to ensure homogenous heating of the sample was achieved. [0110] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.