Method and apparatus for steam pasteurization of meat

FIELD OF THE INVENTION

This invention relates generally to apparatuses and processes for cleaning meat, and more particularly, to a processor and method for destroying coliform bacteria and other surface pathogens on meat.

BACKGROUND OF THE INVENTION

Concerns over pathogens on meat have been elevated in recent years due to

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-

coli

related illnesses and deaths. In response, certain regulations have been imposed on food preparers and recommendations have been made to increase the likelihood that pathogens are killed. For example, restaurants must cook hamburger at 160° F. throughout for at least five seconds.

Such end user regulations have been made in an attempt to correct a problem that begins during meat processing.

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-

coli

, other coliform bacteria, and many other pathogens reside on the surface of meat beginning with the meat carcass processing. The pathogens originate from fecal matter and other contaminants on the surface of the meat. Without adequately destroying these pathogens, the meat is processed, packed, and shipped to the distributor, retailer, or consumer. It is then left to the consumer or preparer of the meat to address a problem that by then can be even worse. The bacteria may have further grown or may reside throughout the meat. This is the case, for example, with ground meat since during meat processing the surface pathogens are distributed throughout the meat.

The only precaution currently taken by the meat processors is to spray the carcasses with water at 120-140° F. This measure is not necessarily effective or efficient at destroying the surface pathogens. Not all pathogens are killed at these temperatures and large volumes of water are required, along with a large amount of energy to heat the water, since the water cannot easily be recirculated if contaminants are to be avoided.

An apparatus has been developed to steam pasteurize meat. This apparatus includes a steam pasteurization chamber that moves in synchronization with a conveyor containing the meat. It has been found that operation of this device may result in breakdowns and does not ensure that the meat has been heated to a sufficient temperature. There is a need for methods and apparatuses that operate more reliably and with controls to heat the meat to sufficient temperature to reduce surface contamination.

SUMMARY OF THE INVENTION

The difficulties and drawbacks of the prior art methods and apparatuses for destroying coliform and other pathogenic bacteria on the surface of meat such as beef, poultry, pork and other meat products may be overcome by the apparatuses and methods of the present invention. The apparatuses and methods of the present invention destroy pathogenic bacteria and other harmful contaminants on all the surface areas of the meat without introducing chemicals or other harmful and expensive products into the process. The methods and apparatuses are also carried out effectively and inexpensively.

One embodiment of the invention includes a method of reducing surface contamination of meat. A surface of a piece of meat is dewatered using a dewatering fluid. The piece of meat is moved into a stationary steam region of a contamination-reducing apparatus. The piece of meat is then stopped within the steam region. Steam is directed toward the piece of meat to heat the surface of the piece of meat. The piece of meat is then moved out of the steam region and a coolant fluid is directed toward the piece of meat to cool the surface of the piece of meat. In some instances, the steam is discontinued after the steam region has achieved a threshold pasteurization temperature and the steam has been directed at the meat for at least a minimum pasteurization time.

Another method of reducing surface contamination of meat includes dewatering a surface of a piece of meat using a dewatering fluid. The piece of meat is moved into a stationary steam region of a contamination-reducing apparatus. The piece of meat is then stopped within the steam region. First and second steam valves are opened to direct steam toward the piece of meat to heat the surface of the piece of meat. The piece of meat is then moved out of the steam region and a coolant fluid is directed toward the piece of meat to cool the surface of the piece of meat. In some instances, the second steam valve is closed after a valve let down time and the steam from the first steam valve is discontinued after the steam region has achieved a threshold pasteurization temperature and the steam has been directed at the meat for at least a minimum pasteurization time. If the steam region does not achieve a threshold pasteurization temperature, the second steam valve is reopened. In some cases, if the steam region does not achieve the threshold pasteurization temperature by a maximum pasteurization time after the second steam valve is opened, an alarm is activated.

An apparatus for reducing surface contamination of meat includes a dewatering region, a steam region, a coolant region, and a controller. The dewatering region includes at least one dewatering element for directing a dewatering fluid at a piece of meat to remove surface water from the meat. The steam region includes at least one steam valve for directing steam at the piece of meat to heat the surface of the meat. The coolant region has at least one coolant element for directing a coolant fluid at the piece of meat to cool the meat. The controller is configured and arranged to control a conveyor to move the piece of meat from the dewatering region to the steam region, to stop the piece of meat in the steam region while steam is directed at the piece of meat, and to move the meat from the steam region to the coolant region.

Another method of reducing surface contamination of meat includes opening an entrance door to a stationary steam region of a contamination-reducing apparatus and moving the meat into the stationary steam region. The entrance door is closed and steam is directed toward the meat to increase a surface temperature of the meat to destroy, for example, coliform and other pathogenic bacteria. The temperature in the steam region achieves at least a threshold pasteurization temperature. An exit door is then opened and the meat is moved out of the steam region. The meat is then typically cooled using a coolant fluid to prevent substantial cooking at the surface of the meat.

The above summary of the present invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The Figures and the detailed description which follow more particularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1

is a schematic plan view of the process and apparatus of the present invention illustrating the movement of a side of beef along an overhead conveyor through the various chambers of the present invention;

FIG. 2

is a semi-schematic elevational view of the dewatering chamber of the present invention;

FIG. 3

is a semi-schematic elevational view of the steam chamber;

FIG. 4

is a semi-schematic elevational view of the chilled water chamber of the present invention;

FIG. 5

is an isometric view of another preferred embodiment of the present invention showing meat being moved through a processor;

FIG. 6

is a top view of the processor of

FIG. 5

showing a steam chamber in a retracted position;

FIG. 7

is a top view of the processor of

FIG. 5

showing the steam chamber being retracted as the meat continues to move in a downstream direction;

FIG. 8

is a cross-sectional elevational view showing the steam chamber in the position shown in

FIG. 6

;

FIG. 9A

is a cross-sectional end view showing the circulation of steam through the steam chamber,

FIG. 9B

is a cross-sectional end view showing the coolant water being sprayed on a carcass after the steam chamber has been retracted;

FIG. 10

is a sectional view showing the functioning of the protection plenum ventilation system;

FIG. 11A

is an enlarged, fragmentary top view showing the entrance door;

FIG. 11B

is an enlarged, fragmentary top view showing the exit door, and

FIG. 12

is an isometric view of an alternate preferred processor including dewatering, steaming, and cooling structures with a moving chamber;

FIG. 13

is a schematic view of a system for generating and supplying steam to the steam chambers of the present invention;

FIG. 14

is a schematic representation of a controller for use with an apparatus of the present invention;

FIGS. 15A and 15B

illustrate a flow chart of one method for a steam pasteurization portion of a process of the present invention; and

FIGS. 16A and 16B

illustrate a flow chart of a second method for a steam pasteurization portion of a process of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The present invention is believed to be useful in the reduction of surface contamination of meat, including beef, pork, and chicken. In particular, the present invention is directed to methods and apparatuses for the steam pasteurization of the meat to heat the surface of the meat and reduce surface contamination. The present invention is described with respect to a previous apparatus and method which is modified according to the invention. However, it will be understood that other apparatuses and methods may be prepared according to the invention.

One example of an apparatus for destroying pathogens on meat includes a dewatering region, a stationary steam region, a coolant region, a meat conveyor, and a controller for controlling the movement of meat through the apparatus. The dewatering region includes, for example, an air blower with nozzles for blowing air at the surface of the meat to remove surface water from the meat. The steam region is disposed adjacent the dewatering region. The steam region may include a steam chamber that is sealed for maintaining a positive pressure in the steam region relative to the dewatering region. The steam region also includes a steam supply line for filling and maintaining the steam region with steam. The coolant region is disposed adjacent the steam region opposite from the dewatering region. The coolant region has nozzles for spraying, for example, chilled water onto the surface of the meat for rapidly cooling the meat, after it is passed through the steam region. The meat conveyor extends through the dewatering region, the steam region, and the coolant region. The meat conveyor supports the meat and transfers it from region to region.

The steam region may further include a floor that is sloped to collect the condensate that drips from the meat. At the lowest point in the floor a pressure retaining drain allows the water to be channeled away from the steam region without release of pressure therefrom. The steam chamber may also include pressure retaining entrance and exit doors to maintain the positive pressure in the steam region as meat enters and exits the steam region. The steam region may also include a steam distribution system extending along the length of the steam chamber and including outlets to dispense steam into the steam region.

The air nozzles in the dewatering region are preferably arranged in banks on either side of the conveyor that transfers the meat, such that the meat is advanced between the two banks of air blower nozzles. An enclosure around these air nozzle banks is also preferably provided.

The coolant region may also include water spray banks on either side of the conveyor for spraying chilled water over the entire surface of the meat. An enclosure may also surround the chilled water sprayers to form a coolant region.

The process may be monitored by recording heat-treating conditions of the first unit of meat by ascertaining the initial surface temperature, the surface temperature as the meat is subject to the steam and the surface temperature after being chilled. The length of heat treatment may also be ascertained and recorded. Rather than measuring the surface temperature of each unit of meat within the steam chamber, this information may be determined by measuring the temperature within the steam region as the meat is being transferred into the steam region, during the steam treatment process and also during the cooling process. Standard temperature gauges may be utilized for monitoring the temperature within the steam region.

The steam chamber includes an entrance door attached thereto at the upstream end of the steam chamber. An exit door is also provided attached to the steam chamber at the downstream end. The exit door preferably includes curved panels with concave sides facing the interior of the steam chamber. The panels include actuators for opening and closing the steam chamber.

The cooling system preferably includes fluid jets attached to the frame. The fluid jets may be water jets, air jets or other types of jets.

The Previous Apparatus and Method

A schematic diagram of one preferred embodiment of the present invention is shown in

FIG. 1. A

processor

10

is provided to rid the surface of unskinned or skinned meat M of any pathogens, such as

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coli

0157:H7 and other coliform-type bacteria, listeria, and salmonella. Processor

10

includes three chambers: a dewatering chamber

12

, a steam heating chamber

14

, and a chilled water cooling chamber

16

. Meat M passes through each of these chambers in series. After passing through chilled water chamber

16

meat M has been cleansed from surface bacteria and is ready to be further processed by cutting, packaging, freezing, or otherwise. Note that while the preferred embodiment refers to beef, other meat can be processed with the apparatus and method of the present invention, such as pork or poultry. Also, while in the preferred embodiment the meat passes through different chambers to be processed, the meat could remain stationary while the process steps are carried out with corresponding equipment.

The first section of processor

10

entered by meat M is dewatering chamber

12

. Dewatering chamber

12

includes a dewatering chamber enclosure

18

to seal off dewatering chamber

12

from external moisture or pollution. A processor entrance door

20

is provided at one side of dewatering chamber enclosure

18

to allow meat M to pass into dewatering chamber

12

. Processor entrance door

20

, as well as the other doors referenced below, is constructed in a pinwheel fashion with a plurality of door arms

22

extending outwardly from a central vertical axis about which the arms

22

rotate. A shield

24

is formed in circular arc sections to engage the outer ends of door arms

22

. Shield

24

includes arcuate portions on both sides of door arms

22

such that a positive closure of dewatering chamber

12

is always achieved as door arms

22

rotate. At least two of door arms

22

will always be in contact with shields

24

to enclose the entrance to the dewatering chamber

12

.

Alternatively, dewatering chamber

12

may be omitted from processor

10

. The meat M would then simply enter steam chamber

14

directly.

Meat M rides through processor entrance door

20

hanging from a conveyor

25

. Conveyor

25

is preferably constructed in a known fashion as a standard meat conveyor with an overhead chain to move the product along a processing stream. However, other conveyor systems may also be used.

After meat M passes through processor entrance door

20

it travels along conveyor

25

between left and right air banks

26

and

28

. Air banks

26

and

28

remove surface moisture from meat M prior to meat M entering into steam chamber

14

. Further details of air banks

26

and

28

are discussed below in connection with FIG.

2

.

Conveyor

25

then carries meat M to the exit side of dewatering chamber

12

and into the steam heating chamber entrance door

30

. Steam chamber entrance door

30

closes the air path between dewatering chamber

12

and steam chamber

14

such that a positive seal is created between the two chambers. Steam chamber entrance door

30

is preferably similar in construction to processor entrance door

20

. However, besides prohibiting contamination from entering steam chamber

14

, stream chamber entrance door

30

also provides an air seal so that a positive pressure may be created in steam chamber

14

relative to dewatering chamber

12

.

Steam chamber

14

includes a steam chamber enclosure

32

which functions to hold steam and a positive pressure therewithin. Conveyor

25

runs through steam chamber

14

from steam chamber entrance door

30

to a steam chamber exit door

38

. Within stream chamber

14

a steam delivery pipe

34

delivers steam to a steam distribution pipe

36

which extends along the steam chamber

14

. Further details of steam chamber

14

will be discussed below in connection with FIG.

3

.

Meat M then passes through steam chamber exit door

38

into cooling chamber

16

. Steam chamber exit door

38

is similar in detail to steam chamber entrance door

30

. Cooling chamber

16

includes an enclosure

40

that keeps the spray of chilled water within chamber

16

and keeps contaminants away from meat M. Cooling chamber

16

includes left and right chilled water spray banks

42

and

44

, respectively. A processor exit door

46

is provided at the output side of chilled water chamber

16

. Preferably, processor exit door

46

is similar in construction to processor entrance door

20

. Conveyor

25

then carries meat M from processor

10

.

As seen in

FIG. 2

, conveyor

25

also includes a hook

48

. Hook

48

is used to secure meat M such that meat M hangs therefrom as it travels through chambers

12

,

14

, and

16

.

The details of dewatering chamber

12

will be discussed. Dewatering chamber

12

includes air manifold pipes

50

with nozzles

52

. Manifold pipes

50

and nozzles

52

form left and right air banks

26

and

28

. Nozzles

52

shoot air at high velocity at meat M to substantially remove surface water that may reside on the surface or in the crevices of meat M. The high pressure air is provided by left and right blowers

54

and

56

. The air travels from the blowers through air pipe

50

and out nozzles

52

against meat M. Air banks are positioned on both sides of meat M so that standing areas or droplets of surface water are substantially removed from the entire surface of meat M before entering steam chamber

14

. Removal of substantially all significant amounts of standing surface water is preferred so that, once within steam chamber

14

, a significant amount of heat is not absorbed by surface water but instead is transferred directly to the surface of the meat to destroy pathogens. The surface of the meat may still be moist to the touch, but dewatering removes most standing water, whether it be areas of water on the meat surface, or just droplets of water.

Referring now to the semi-schematic elevational view of steam heating chamber

14

illustrated in FIG.

3

. An entrance valve

58

is provided at the top of steam chamber and closure

32

to deliver steam

60

through delivery pipe

34

and distribution pipe

36

. Steam

60

is continually pumped into heating chamber

14

through pipe

36

such that a positive pressure is created within heating chamber

14

. The preferred pressure differential is about two inches of water. Other positive pressures could be used, preferably falling anywhere from about one-half to five inches of water relative to dewatering chamber

12

and the cooling chamber

16

as well as the outside environment. However, as little as 0.01 inches of water pressure may be used. A positive pressure within steam chamber

14

helps to ensure that steam

60

very rapidly comes into contact with all surface areas of meat M and air is excluded from steam chamber

14

.

As steam

60

contacts and surrounds meat M after it passes through steam chamber entrance door

30

, steam

60

heats the surface of meat M. Steam

60

within heating chamber

14

is preferably at 212° F. at saturation. The steam

60

may be superheated to a temperature above 212° F. A pressure relief valve

62

is in communication with the heating chamber enclosure

32

to maintain the desired positive pressure within heating chamber

14

.

As steam

60

envelops and contacts the surface of meat M, heat is drawn into the surface of meat M through steam contact. Steam condenses on the surface of meat M. The condensation of steam

60

onto the surface of meat M produces a transfer of heat energy, specifically the change-of-state energy from steam

60

, to the surface of meat M. This transfer of energy heats the surface of meat M very quickly and effectively to kill any pathogens residing thereon.

As the condensation continues, water drips to the bottom of steam chamber

14

. Steam chamber

14

is provided with a sloped floor

64

and a drain

66

at the bottom thereof to collect this water. Drain

66

is constructed such that pressure does not escape therefrom.

Meat M is preferably kept within steam chamber

14

for approximately 2½ to 30 seconds, 10 seconds being optimal. The surface of meat M is heated one to five microns deep at approximately 160° F.-198° F. during this time. Meat M may also stay within steam chamber

14

a longer amount of time. However, between 2½ to 30 seconds is a preferred amount of time to maintain the surface of meat M between 160 and 198° F. to sufficiently reduce coliform bacteria, salmonella, and other pathogens. The preferred temperature range at the surface of meat M is between 160° F. to 198° F. The time within steam chamber

14

may be set by the speed of conveyor

25

combined with the length of steam chamber

14

. The temperature of the meat surface may be extrapolated from temperature measurements taken at various locations, preferably about four, within steam chamber

14

.

Cooling chamber

16

is provided to very rapidly dissipate the heat and thus stop the transfer of heat into meat M. Meat M enters into cooling chamber

16

after it passes through steam chamber exit door

38

. See FIG.

4

. Once within cooling chamber

16

, conveyor

25

transfers meat M between left and right spray banks

42

and

44

. Chilled water at preferably about 40° F. is supplied by water supply pipe

68

. The water passes through water valve

70

and into water delivery pipes

72

. The water is under pressure such that it sprays through water nozzles

74

to contact and thus quickly chill the surface of meat M to remove the heat and provide a final rinse.

Meat M continues along the path of conveyor

25

through processor exit door

46

. Meat M exits in a clean state with the surface of meat M effectively pasteurized from any fecal matter and the pathogens that accompany it or other contaminants that may be on the surface of meat M.

In summary, meat M passing through a dewatering chamber to remove excess moisture therefrom prevents surface moisture from absorbing the heat energy from the change of state of the steam in steam chamber

14

to condensation on the surface of meat M. This heat energy effectively destroys the pathogens. Afterwards, the chilled water in cooling chamber

16

rapidly cools the meat so that it is not significantly heated on the surface. This process is clean and effective. It does not employ objectionable chemicals, bacteria, radioactivity, or other expensive processes while ensuring that pathogens such as coliform bacteria, listeria, and salmonella are eliminated from the meat.

FIG. 5

illustrates another preferred embodiment of the present invention. In this embodiment, a processor

110

destroys any disease-carrying material on the surface of the meat while the meat M is moving continuously along a conveyor path. It is not necessary to stop the conveyor path but if the conveyor should stop while the meat is in the middle of processor

110

, the meat is effectively cleansed and cooled.

Processor

110

includes a dewatering station

112

, a steam chamber

114

, and a cooling chamber

116

. The stream chamber

114

and cooling chamber

116

are both contained within an outer enclosure

118

. Outer enclosure

118

is generally parallelepiped in shape and includes an outer enclosure floor

119

that is peaked along the longitudinal center line of the floor. The floor

119

slopes towards the outsides of outer enclosure

118

for collection of condensate runoff from the meat. The cross-sectional size of outer enclosure

118

is somewhat larger than the typical size of a unit of meat M. The length of outer enclosure

118

is approximately 33 feet in the embodiment shown in

FIG. 5

that is adapted for use with sides of beef. Of course, the size, including the length, of the enclosure may be varied to accommodate different numbers of sides of beef to be treated at the same time and also for different types of meat, e.g., pork or poultry.

The processor

110

resides primarily below a standard conveyor

120

that is within the processing plant. A conveyor

120

includes a track

122

extending generally horizontally above the center of outer enclosure

118

. Rollers

124

ride on top of track

122

and are pulled along by a drive chain

125

. Hooks

126

extend below rollers

124

and into outer enclosure

118

as they move through processor

110

. The meat M hangs from hooks

126

for processing.

The first stage of processor

110

includes dewatering station

112

. Dewatering station

112

includes right air bank

128

and left air bank

130

positioned on the right and left sides of conveyor

120

respectively so as to direct a drying fluid, such as air, at the surfaces of meat M before meat M enters outer enclosure

118

. As explained above with reference to the previously described embodiment, it is important to remove excess water from the surface of meat M before it enters steam chamber

114

so that effective heat transfer destroys any bacteria residing on the surface of meat M. Ideally, the drying air is directed at the meat shown in

FIGS. 5-8

at a pressure of about 15 psig and at a high volume, i.e., of about 7000 cubic feet per minute. Air banks

128

and

130

may alternatively be arranged in a different fashion. Also, other excess water removal methods may be employed.

Steam chamber

114

ideally extends approximately half of the length of outer enclosure

118

. Also ideally steam chamber

114

rides within outer enclosure

118

at all times. Steam chamber

114

includes side walls

134

for enclosing meat M. The steam chamber is illustrated as sized to accommodate four units of meat M (e.g., carcasses) at the same time. A steam supply header

136

is attached to the top of outer enclosure

118

and directs steam into steam chamber

114

as described below with reference to

FIG. 9A. A

pair of steam ventilation ducts

138

are also provided, attached to the top of outer enclosure

118

on either side of steam supply header

136

. Steam ventilation ducts

138

are used to evacuate the steam S from steam chamber

114

as described below in further detail in connection with

FIGS. 9A and 9B

.

A protection plenum

140

is provided all along the length of outer enclosure

118

immediately below track

122

. Protection plenum

140

is a longitudinal enclosure provided with a negative pressure by pulling a vacuum with protection plenum duct

142

in order to keep any steam seepage from contact with the rest of conveyor

120

. Preferably, protection plenum duct

142

is connected to at least two locations along trolley protection plenum

140

in order to create negative pressure within the protection plenum and to thus avoid damage to conveyor

120

.

Steam chamber

114

also includes support wheels

144

disposed at the bottom of side walls

134

. Support wheels

144

support steam chamber

114

above enclosure floor

119

so that steam chamber

114

may move longitudinally within outer enclosure

118

.

A chamber drive

146

is attached ideally near the middle of outer enclosure

118

between outer enclosure

118

and steam chamber

114

in order to move steam chamber

114

within outer enclosure

118

. Chamber drive

146

preferably includes a servo drive, a brake, a gear motor and a pinion

148

. Pinion

148

is positioned at the bottom of chamber drive

146

and along the side of the bottom of steam chamber

114

. Racks

150

are provided all along the bottom of side walls

134

of steam chamber

114

. Thus, steam chamber

114

may be moved within outer enclosure

118

by rack

150

being driven by pinion

148

of chamber drive

146

.

Horizontally disposed guide wheels

152

are also provided to engage the outer surface of rack

150

in order to prevent yaw of steam chamber

114

while it is being moved within outer enclosure

118

. Guide wheels

152

are rotatably journeyed on stationary brackets to the inside of outer enclosure

118

. Chamber drive

146

is switched on when steam chamber

114

is filled with a desired number of units of meat M and moves steam chamber

114

at substantially the same rate of speed as conveyor

120

, such that it moves along with meat M for a set period of time to apply steam S to meat M. Chamber drive

146

then quickly retracts steam chamber

114

to its start position as explained below.

Entrance doors

154

(not shown in

FIG. 5

) and exit doors

156

are provided on the ends of steam chamber

114

in order to seal the chamber for application of steam S. Door actuators

158

are mounted to side walls

134

of the steam chamber

114

in order to open and close entrance and exit doors

154

and

156

.

The downstream end of outer enclosure

118

contains chilled fluid banks

160

. Chilled fluid banks

160

include pipes which channel a cooling fluid, preferably water, to coolant nozzles

162

. Coolant nozzles

162

are directed to meat M to spray a coolant fluid on the surface of meat M in order to quickly reduce the surface temperature of meat M after steam chamber

114

is retracted from meat M. Once meat M passes between chilled fluid banks

160

harmful surface bacteria has been destroyed and meat M is ready to move on to additional processing steps and shipment to retailers and consumers.

FIGS. 6

,

7

and

8

illustrate the movement of steam chamber

114

within outer enclosure

118

while meat M is processed with processor

110

. Meat M is supported by and moves along conveyor

120

during the entire process. Ideally the conveyor is moving at a substantially constant speed, but occasionally the conveyor speed may change, or the conveyor may even stop. Nonetheless, the present invention is capable of accommodating this change in conveyor speed.

As meat M enters into outer enclosure

118

it moves through entrance doors

154

into steam chamber

114

. The distance between side walls

134

of steam chamber

114

is sufficient to enclose meat M therein. The length of steam chamber

114

is preferably long enough to enclose a desired number of units of meat M. Although four units are shown enclosed in

FIGS. 6

,

7

and

8

, the length of the steam chamber

114

may be designed to accommodate a different number of units and also various types of meat.

Once four units of meat M enter into steam chamber

114

, entrance door

154

and exit door

156

are closed by actuators

158

. As soon as this occurs, steam chamber

114

begins to move along with meat M at the same rate as the movement of meat M while filling with steam (about 7.1 inches per second). Steam surrounds meat M preferably at a temperature of about 212° F. at sea level for a preferred length of time of 10 seconds. The temperature may be anywhere within the range of about 175° F.-500° F. and preferably surrounds the entire surface of meat M for a period of time between about 5 seconds and 30 seconds. The pressure within the chamber may be positive relative to ambient pressure to maintain steam purity. Temperature measurements are preferably taken at about four locations within steam chamber

114

and used to determine the temperature of the atmosphere within the steam chamber during the present process. Steam chamber

114

is moved within outer enclosure

118

by chamber drives

146

acting on rack

150

. Guide wheels

152

stabilize the movement of steam chamber

114

as it moves with meat M.

As seen in

FIG. 7

, once the desired time for application of steam to the surface of meat M has been met, entrance and exit doors

154

and

156

are opened and steam chamber

114

is quickly retracted back (preferably at about 12 feet per second) to the upstream end of outer enclosure

118

to enclose additional meat M to begin the process over again. Meanwhile, as shown in

FIG. 6

, meat M that has been treated, continues to move through outer enclosure

118

within cooling chamber

116

. Chilled fluid banks

160

spray coolant on the outer surfaces of meat M to rapidly decrease the surface temperature of meat M. This coolant prevents meat M from being cooked at its surface. The coolant W directed at meat M through nozzles

162

may be any coolant fluid such as air, water, or water, perhaps with an antimicrobial agent mixed therein. Specific antimicrobial agents that may be used include lactic acid, trisodium phosphate, acetic acid, and chlorine dioxide.

Should conveyor

120

stop, steam chamber

114

will also be stopped by a switch that is triggered by movement or nonmovement of conveyor

120

. Steam continues to be applied to meat M for the desired period of time after which doors

154

and

156

are opened and air is rushed through steam chamber

114

to evacuate steam S and to provide a cooling effect on meat M. Also, simultaneously the flow of chilled fluid may be started, which would assist in rapidly cooling the meat even though the fluid may not be actually spraying the surface of the meat. Thus, processor

110

can process meat with the continually moving line or with inadvertent stops in the line as meat M moves through processor

110

. As such, the remaining processes within the plant that may cause conveyor

120

to stop can go on without worry of processor

110

and meat M being adversely affected.

FIGS. 9A and B

illustrate the movement of steam S through steam chamber

114

.

FIG. 9A

illustrates the steam supply cycle as steam surrounds meat M and simultaneously pushes out any air surrounding meat M. Steam enters through steam supply header

136

through the top of outer enclosure

118

. Chamber seals

164

provide a sealing engagement between the top of steam chamber

114

and outer enclosure

118

. Steam supply header enters within the inside of chamber seals

164

such that the steam is channeled within side walls

134

of steam chamber

114

. First and second deflection plates

166

and

168

, respectively, are provided along the top of side walls

134

of steam chamber

114

. First deflection plate

166

is nearest to steam supply header

136

and channels steam, as explained below in connection with FIG.

10

. Steam then surrounds and moves down along the top and sides of meat M while simultaneously pushing air out the bottom of steam chamber

114

through gas escape openings

170

. Gas escape openings

170

are provided along the bottom of steam chamber

114

to allow air and steam to be pulled out of the bottom of steam chamber

114

up and through steam ventilation duct

138

. As steam S is pumped into steam chamber

114

the heavier air moves toward the bottom and is pulled out of steam chamber

114

along the sides of steam chamber

114

within outer enclosure

118

. Thus, steam uniformly covers the surface of meat M without any substantial air pockets. This ensures that adequate heat transfer takes place at the surface of meat M without any insulating effect of air. The volume of steam supplied to the steam chamber

114

to purge the chamber and treat the meat M is ideally about three to four times the volume of the steam chamber. However, depending on the temperature and pressure of the steam and other factors, more or less steam may be supplied to the steam chamber.

FIG. 9B

illustrates the cooling of meat M after steam is evacuated from steam chamber

114

and steam chamber

114

is retracted from meat M which is now advanced to the downstream end of outer enclosure

118

.

FIG. 10

illustrates in further detail the flow of steam into steam chamber

114

, as well as the functioning of protection plenum

140

. As steam moves from steam header

136

it is channeled toward meat M with first deflection plate

166

. First deflection plate

166

is approximately 40% open with holes formed therein, such that it allows some steam to enter directly to the top of meat M to fill steam chamber

114

, while channeling additional steam to the opposite side of meat M to be directed down through second deflection plate

168

which is approximately 60% open. Thus, steam substantially evenly moves down all sides of meat M. Other ratios of openness of deflection plates

166

and

168

may be used depending on the pressure and volume of steam supplied, such that steam moves evenly over the surface of meat M to push air out the bottom of steam chamber

114

so that no pockets of air remain on the surface of meat M.

Also illustrated in further detail are chamber seals

164

. Chamber seals

164

include an upper member

186

which is an inverted U-shape and a lower member

188

projecting upwardly from the top of outer wall

132

to meet within upper member

186

. Upper members

186

effectively forms a channel beneath the top side of outer enclosure

118

. Thus, little or no steam escapes through chamber seal

164

.

Protection plenum

140

provides a channel for capturing escaped steam along the top of outer enclosure

118

beneath track

122

. Steam is pulled out of protection plenum

140

with plenum ventilation duct

142

such that a negative pressure is maintained within protection plenum

140

, relative to the interior of steam chamber

114

and to the ambient air. An upper plenum wiper seal

172

constructed of two strips of flexible rubber or similar material, that are angled upwardly and inwardly toward each, is provided at the top of protection plenum

140

to allow a nominally closed slot through which a conveyor brackets

184

may slide. When a conveyor bracket

184

is not between upper plenum seal

172

, the two strips contact against each other to block steam from exiting the plenum. While brackets

184

pass along seal

172

some small openings may occur. However, since a negative pressure relative to the outside environment is maintained, air will be pulled into protection plenum

140

to be evacuated with steam S through plenum ventilation duct

142

. Likewise, a lower plenum seal

174

is provided just above hook

126

to seal the lower side of protection plenum

140

and to evacuate any steam that may escape from outer enclosure

118

and from steam chamber

114

. Lower plenum seal

174

also includes two rubber strips (or similar material) that are angled upwardly to meet at their uppermost ends and to provide a normally closed slot through which bracket

184

may slide.

FIGS. 11A and B

illustrate the details of exit door

156

(

FIG. 11B

) and entrance door

154

(FIG.

11

A). Exit door

156

includes door arms (halves)

176

that are pivotally attached to side walls

134

for sealing closure therewith. Actuator brackets

178

are secured to the outsides of side walls

134

and include a pivotal attachment to door actuators

158

. The opposite end of door actuators

158

are secured to door brackets

180

. Thus, retraction of actuator

158

causes door

156

to open while extension of actuators

158

causes door

156

to close. Door

156

includes door arms

176

, each attached to a door bracket

180

. The free ends of door arms

176

include hook-shaped door seals

182

that may be compressed one to another to provide an effective seal in the middle of door

156

. The curved shape of door arms

176

, with their connection to actuators

158

, allows doors

156

to be opened and closed with minimal movement and space requirements outwardly from inner walls

134

. Also, door

156

will open automatically when pushed by meat M.

Entrance doors

154

are somewhat similarly constructed. However, entrance doors

154

include actuators

158

attached to brackets fixed to outwardly extended portions of side walls

134

. Side walls

134

flare outwardly near the upstream end of chamber

114

after which they extend in approximately parallel planes to the upstream end of chamber

114

. This wider region of side walls

134

is necessary to accommodate the opening of door

154

inside of side walls

134

. The pivot point of door arms

176

are at the upstream end of side walls

134

. Supports

184

are provided to serve as a pivot for bracket

180

of door arms

176

.

Another preferred alternate embodiment of the invention is provided and will be described in connection with FIG.

12

. In this embodiment removal of excess surface liquid from the meat M, the application of steam to the meat, and cooling, is all carried out within moveable chamber

214

. Except for the elements described below, the aspects of this embodiment are similar to those described above with respect to

FIGS. 5-11

. For example, an outer enclosure

218

, similar to enclosure

118

is provided along with a conveyor

220

and track

222

. A protection plenum

240

, similar to protection plenum

140

is also provided as well as a plenum duct

242

, a steam supply header

236

and a steam ventilation duct

238

.

However, in the embodiment of the present invention show in

FIG. 12

, in order to carry out all steps within chamber

214

, air banks

228

and chilled water banks

260

are secured to the inside of side walls

234

of chamber

214

. Air banks

228

are illustrated as extending in columns down both of the insides of side walls

234

. Air banks

228

include openings for blowing a coolant fluid, such as air, at the surface of meat M to remove excess surface liquid. The excess liquid is removed before steam is applied to the surface of meat M within chamber

214

as meat M moves along conveyor

220

. Air banks

228

are connected to air supply lines

290

which extend to within the top of enclosure

218

. Air supply lines

290

are coupled to flexible air hoses

292

that extend within chamber

214

to be connected to air banks

228

. Flexible air hoses

292

are used with extra length to enable movement of chamber

214

, while maintaining a constant connection with fixed air supply lines

290

. The fluid for removing excess liquid from meat M may be obtained from fluid supply tanks or simply from ambient air.

Similarly, chilled water banks

260

are connected to flexible coolant hoses

296

that run to coolant supply lines

294

. Again, the flexibility of flexible coolant hoses

296

allow chamber

214

to move relative to coolant supply lines

294

while still maintaining a constant supply of coolant fluid for cooling meat M within chamber

214

as meat M moves along conveyor

220

.

The process of this alternate embodiment begins with meat M entering into entrance door

254