Process for Preparing Food in the Package

The invention relates to an apparatus and system for the packaging and preparing of foods.

The shelf life of fresh foods such as fresh baked goods now sold in supermarkets is limited to 3 or 4 days storage at room temperature primarily because of mold growth. Products now being distributed in a refrigerated condition will usually develop mold as evidenced by a green color on the surface within 40 days. At room temperature, the mold often develops on the surface of bakery goods for example, within about seven days. The present invention has as its general objective the provision of an apparatus and system that will eliminate this problem thereby allowing foods such as baked goods to be shipped refrigerated at 40.degree. F. or 70.degree. F. (i.e. room temperature) with no evidence of mold after 120 days of storage.

Previous apparatus and systems proposed for packaging and preparing bakery goods that are both a) sterile with respect to mold, and b) will not be contaminated during or after baking, have produced erratic results in that a small but significant number of failures occur, particularly where hand wrapping or other hand operations are required. Hand operations have also been slow, expensive and introduce an opportunity for either microbial contamination or packaging malformation.

The production of sterile or virtually sterile bakery goods and other foods has been carried out in both flexible or rigid containers. Pound and spice cake has, for example, been supplied in ordinary tin cans. It has also been proposed to produce sterile bakery goods in flexible pouches formed from laminates of aluminum foil and plastic by filling the pouch with dough or batter, placing it in water filled retort and heating it until sterile while the external pressure is controlled to prevent the pouch from bursting or from being collapsed by excessive external pressure. It has also been proposed to place dough in a tray or pouch of flexible material which is transferred into boiling water through an inlet water leg and removed through an outlet water leg to control the externally applied pressure during cooking. A disadvantage in these processes is that ordinary baking ovens cannot be used.

It has also been proposed in the past to bake bread that resists spoilage in ordinary baking ovens by manually wrapping dough in a sheet of moisture proof paper, baking the dough in the wrapper and hand sealing the wrapper after baking. This process is complicated, time consuming and requires a substantial amount of manual handling which is not only objectionable because of its cost and the special training required, but it also provides an additional opportunity for bacterial and fungal contamination of the dough surface due to the finger contact.

The term "sterile" as used herein means containing no viable mold spores. The expression "bakery goods" means having a content of a farinaceous food, e.g. bread or cake, cookies, etc., with or without a filling such as fruit, sauce, meat or the like.

The major objects of the invention are to provide an apparatus and system for forming a package of sterile bakery goods which a) can be kept in a wholesome condition for 120 days without the formation of mold, b) exhibits good flavor and texture after 120 days of storage at either refrigerated or room temperature when warmed in a baking oven, c) is relatively inexpensive to operate and can utilize ordinary baking ovens, that is to say an electric, gas or oil fired hot air oven, d) has means for preventing contact between the dough and portions of the package where the dough is likely to stick, e) employs a package or container that is relatively inexpensive, light in weight and allows the food product to be seen clearly, f) allows accomplishment of the above objectives without preservatives in the dough, g) provides a loaf of bread or other bakery goods that exhibit good keeping qualities in the home so that the package can be kept on the shelf in the kitchen for several days or weeks and can be distributed by a bakery from a single location through the entire country, h) is capable of continuously producing filled packages that can be baked in large commercial size bakery band ovens three meters or more wide, i) is capable of packaging up to about 20,000 lbs. of dough .+-. 25% per hour, j) has provision for preventing the product from being crushed by vacuum after the package is sealed, and k) allows continuous mass production processing with no manual handling steps either for inserting the loaves in the packages, sealing them or advancing the packages from one location to another, l) is suited for use with a variety of bakery goods including bread, cake, cookies, crackers, rolls, biscuits, muffins, meat, jam or sauce filled bread and rolls or hamburgers and the like.

FIG. 1 is a perspective view of the apparatus.

FIG. 2 is a perspective view of a filled package in accordance with the invention prior to final sealing.

FIG. 3 is a view similar to FIG. 2 after the package is finally sealed.

FIG. 4 is a perspective view of a group of connected packages as they appear emerging from the oven prior to being cut apart.

FIG. 5 is a diagramatic flow chart showing the steps performed in one form of the invention.

According to the present invention an apparatus is provided that preferably comprises a plastic sheet heating and forming means such as a vacuum former to fold or mold the plastic sheet into trays. A food depositor or guide is located adjacent to the vacuum former to place food, e.g., dough in the trays. A sealer such as cooperating heated bars seal a sheet which is usually perforated over the top of each tray and an oven receives the filled trays and bakes the food within the trays. The oven can be an oil, electric or gas fired hot air baking oven. During the baking operation steam escapes through the perforations or vents which are then sealed. During operation, a food such as a flour containing dough or batter is placed in the tray or other suitable flexible package or recepticle. A flexible plastic pouch or tray is preferred. The pouch or covered tray has one or more steam vents at the time baking is carried out. During the baking operation, steam and gas escape through the vent which is sealed at the end of the baking operation.

The invention can be used with a variety of foods in addition to farinaceous foods. Among such foods are hash brown potato, au gratin potato and cooked meat. It can also be used with a variety of vegetables such as cooked corn, cooked carrots as well as hot dishes such as chicken with dumplings, macaroni and spaghetti with or without meat and other foods including hamburger sandwiches in which the meat patty has been cooked, fruit, etc. The invention is particularly useful with bakery goods since products of this kind have a particular shape such as the shape of a roll or loaf of bread, biscuit, muffin and so forth which must be retained up to the time that the product is to be eaten whereas creamed corn, chicken and dumplings, etc. can be formed into any shape and yet will provide an acceptable product. Thus, the advantage of the invention in protecting the delicate shape of bakery products and the like during packaging and cooking and distribution is one of the major advantages of the invention.

When the food is dough, the dough can be either yeast leavened or chemically leavened. Yeast leavened dough is typically composed of flour, water, yeast, sugar and shortening. Yeast leavened dough is compounded and mixed conventionally, preferably allowed to stand for a few minutes. It is then scaled and divided into bread size pieces and proofed. Batch or continuous processing can be used. The pouches can consist of one or more generally rectangular sheets bonded together at their edges. One or both of the sheets can be provided with a tray like trough or recess for holding the piece of dough, cake, cookies, etc. as the case may be.

In one preferred system or method of accomplishing the invention, packages are formed by continuously advancing a sheet of flexible package material, heating the film and periodically forming the heated portions of the film to provide a tray-like depression or recess. The dough pieces are then placed in the recesses and a second sheet of flexible packaging material is sealed over the top of the tray. One or more air vents is provided in the package preferably defined by an unsealed gap between the sealed edges. The dough is then proofed if necessary and heated in an oven at least sufficient to set the crumb structure of the dough. After heating the air vents are sealed either immediately or after a short cooling period. During the cooling period as steam condenses in the package, the package is allowed to inspire sterile air. The package is then sealed, cooled and shipped.

In the accomplishment of the foregoing and related advantages and objectives, this invention then comprises the features hereinafter fully described and particularly pointed out in the claims, the following description setting forth in detail certain illustrative embodiments of the invention these being indicative, however, of but a few of the various ways in which the principles of the invention may be employed.

The packing, forming, filling and sealing apparatus in accordance with the invention is indicated generally by numeral 1 in FIG. 1. It includes a supporting framework composed in part of parallel vertically disposed side plates 1a and 1b suitably joined together by internal frame members (not shown) and cross plates 2a and 2b, etc. some of which can be removed for inspection and cleaning etc.

The left end of the apparatus as seen in FIG. 1 is an arbor 21 which supports a plastic film or web 24 for rotation on the apparatus 1. From the roll the web material 24 is unwound traveling upwardly intermittently during operation over roll 26 which is journaled for rotation at the left end of the apparatus above the arbor 21. From roll 26 the web 24 travels across the top of the apparatus beneath a heater 28 which is capable of supplying sufficient heat to warm the web 24 to thermoforming temperature. Positioned adjacent to and on either side of the heater 28 are a pair of conveying bands 28a and 28b each entrained over parallel longitudinally and laterally spaced pullies that are driven during operation by a drive belt 29 connected to intermittent drive 29a which is in turn driven by a drive motor 29b at the proper speed and direction to carry the web 24 intermittently from left to right beneath the heater 28 and remain there for just the proper amount of time to reach thermoforming temperature at which point motion is again imparted to the web 24 by the bands 28a to carry the then formed sheet toward the right to the filling station to be described below.

The web 24 when it becomes heated to the proper temperature is formed by a vacuum 31 which is applied to a vacuum forming cavity 32 through a line 33 under the control of a vacuum valve 33a. The vacuum cavity 32 includes a plurality of longitudinally and laterally spaced upwardly opening recesses having inclined centrally tapered sidewalls. The recesses or cavities are designated C in FIG. 5. The apparatus includes suitable provision (not shown) such as timing means or limit switch for turning on vacuum 31 by opening valve 33a when the web 24 has been stopped by the intermittent drive 29a for sufficient time to reach thermoforming temperature. The vacuum present in cavity 32 then draws the web 24 downwardly into the upwardly opening cavities C thereby forming the web into a plurality of usually laterally spaced as well as longitudinally spaced pouch portions or trays 34 that define the lower portion of the package being formed.

A cylinder or other equivalent means 32a supports the cavity 32 for upward and downward movement and after the web has been formed is suitably actuated preferably by electrical or pneumatic controls connected to vacuum valve 33a to lower the cavity 32 away from the web 34 so that the web can be advanced the required distance toward the right.

Positioned immediately to the right of the vacuum forming station is provided a tray filling station which includes a hopper 38 containing food such as dough 36 and having the proper number of openings at its lower end to feed the dough into the upwardly opening trays 34. The hopper 38 in most typical applications is not filled with the food product but functions merely as a guide or chute for directing the downward movement of preformed bodies of the food such as the dough balls 36 (FIG. 5). Once the dough ball or loaf 36 has dropped into the tray 34 it takes the position indicated at 40 and its upper surface is spaced somewhat below the upper edge of each tray.

The apparatus includes a pair of upwardly extending support arms 39, only one of which is shown, upon the upper end of which is journaled for rotation at 39a, a roll of a supply web 42 of a flexible packaging sheet material for the upper sheet or cover layer that defines the top of the finished package. During operation the web 42 is drawn intermittently downwardly past a lamp and photocell assembly 43 suitably positioned for sensing marks 43a imprinted on web 42 and connected via conductors 45 to a Timer which is in turn wired by means of conductors 45a and 45b to Motors M and M'. Motor M is suitably connected by a drive sprocket and chain assembly to one of a pair of drive rolls 3a and 3b which intermittently advance the web 42 toward the left in the Figures past a perforator 4 that comprises a pair of laterally spaced blade segments 4a each mounted upon a transversely extending shaft connected via suitable chain sprocket assembly 4b to motor M'. Thus, as the motor M' turns, the blades 4a will periodically produce cuts 55 at laterally spaced positions and at the proper distance longitudinally from one another on the web 42 so that each perforation or cut 55 is located in approximately the center of one end of each of the trays 34 as best seen in FIGS. 2 and 4.

From the perforator 4, the web 42 passes toward the left and downwardly, over idler rollers 5 and 44 and into abutting relationship with the peripheral flange between the freshly formed and filled columns and rows of trays 34.

After the top or cover comprising web 42 has been applied to the upper surface of the trays 34, the filled trays and web 42 pass intermittently toward the right to a sealing station including upper and lower heated sealing elements 47 and 47a respectively comprising longitudinal and transversely extending bars which coincide in position with the flat horizontal peripheral flanges 35 between trays 34. Thus, during operation the heat sealing elements 47, 47a are brought together for example under the influence of a cylinder actuator 47b which swings the upper heat sealing element 47 downwardly about a pivot 47c into contact with web 42 thereby forcing it firmly against the flange 35 of each tray 34, the latter being supported against downward movement by the bars 47a.

In order to allow the trays to move, the lower heat sealing member 47a is raised or lowered periodically by means of a hydraulic or pneumatic cylinder 47d (FIG. 5) which is operated in timed relationship with the operation and cylinder 47b.

The heat sealing elements 47 and 47a are provided with recesses or grooves 53 (FIG. 1) positioned to coincide with one end or side segment of the horizontal flange 35 to thereby provide an unsealed section 54 in the otherwise completely sealed tray for the escape of vapor and steam as will be described below. While it is not essential that the bars 47-47a be provided with grooves 53, it is important that some means be provided for forming the unsealed section 54 as shown in FIGS. 2 and 3. This could also be accomplished by having a portion of the heated element 47 be formed from an insulator material that is not heated. A slot or groove such as 53 is however, the most effective.

The filled and sealed packages are now ready for baking. It is preferred that baking be accomplished with at least some of the trays connected together. For example, a group of a dozen can be left connected together and baked as a unit. Each group can be separated from the next by means of a cutter comprising periodically operated cutting blade 48 and blade backing member 49 (FIG. 5). Following baking the columns and rows of trays which have been baked as a unit can be separated by suitable cutters (not shown).

While the invention is applicable to a wide variety of bakery goods as outlined above, it is particularly useful in connection with yeast or chemically leavened bread and rolls. Typical yeast leavened bread and roll formulas are as follows:

Each of the above formulas is mixed for 15 minutes using a bar or sigma blade mixer. The dough temperature is 81.degree. F. The dough finished is formed into ten ounce loaves.

To prepare a chemically leavened biscuit dough, the following formula can be used.