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USDA 

 

THERMAL PROCESSING 

TRAINING 

Module 9. Steam, Batch, Agitating 

Retorts 

Thermal Processing for Meat and Poultry 

Products Training 

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Common Features 

 Use steam as the heating medium 

 Batch container handling 

 Product agitation 

 End-over-end, side-over-side (axial), and back 

and forth agitation (Shaka®process) 

 COMMON EXAMPLE: FMC Orbitort Sterilizer 

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Orbitort Sterilizer 

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CANS IN 

ROTATING CANS OUT 

REEL A SINGLE 

SHELL 
 

 

 

 

 

Orbitort Features 

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 Designed to process 

medium consistency 

products in large 

institutional size (#10) cans 

 Pressure process and cool 

in one horizontal shell 

 Shell contains an inner and 

outer reel 

 The inner reel contains the 

can steps 

Inner reel 

Outer reel 

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Loading/Unloading the Orbitort 

 Unprocessed cans are loaded and processed 

cans are unloaded at the same time through 

air-operated gate valves 

 Cans enter high on one end of the retort wall 

and exit low on the other end of the retort wall 

 During loading/unloading, the outer reel is 

locked to the retort shell 

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Loading/Unloading the Orbitort 

 The inner reel turns during loading/unloading 

moving unprocessed cans toward the exit end 

and processed cans out of the retort 

 A counter keeps track of the cans loaded into 

the retort 

 A second counter advances the cans two 

turns separating processed and unprocessed 

cans by two spiral turns 

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Loading/Unloading the Orbitort 

 When the retort is full the loading/unloading 

gates are closed 

 The outer "spiral" reel is locked to the inner 

"channel" reel holding the containers in place 

during thermal processing and cooling 

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L11 , cc 

· ORBITORT AGfTATfON 

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O U C 

.. ~­ .... ,t>-7 APII 

0.U l~C 

Side-Over-Side Agitation 

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Continuous Agitation 

 Certain products heat faster when agitated 

 Product and headspace bubble mix during 

rotation 

 Dependent on headspace, consistency, reel 

speed and fill-in weight 

 Reel speeds are faster than continuous rotary 

retort reel speeds 

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Continuous Agitation 

 Advantages: 

• Shorter process time 

• Better product quality and uniformity due to 

shorter process times 

 Disadvantages: 

• Batch handling 

• More critical factors to measure, control 

and record 

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Retort Operation - Venting 

 Must provide for air removal before process 

timing begins 

 Procedures must be supported by heat 

distribution data 

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THERMAL PROCESSING 

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Retort Operation - Pressure Cooling 

 Needed to prevent container distortion 

(buckling) 

 At the end of thermal processing cycle, 

cooling water is introduced into the retort shell 

while the containers are still being agitated 

 When the product is cooled the retort is ready 

for emptying and reloading 

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THERMAL PROCESSING 

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Critical Operating Parameters 

 Headspace and/or fill-in weight 

 Consistency/thickness 

 Reel speed 

 Condensate build-up in the bottom of the shell 

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Headspace 

 Area not occupied by product 

 Critical factor for agitation 

 Net or gross headspace 

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Headspace 

THERMAL PROCESSING 

TRAINING GROSS HEADSPACE 0.250” NET HEADSPACE 0.180” 

MEASURED FROM TOP OF MEASURED FROM LID TO 

DOUBLE SEAM TO LIQUID LIQUID 15 
 

 

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Headspace 

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Measuring Gross 

Headspace: 

A straight edge is 

placed over the 

top edges of an open 

container. The distance is 

measured from the 

bottom of the straight edge 

to the top of the product 

surface. 
Headspace 

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One Type of Headspace Gauge 17 
 

 

 

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Consistency 

 Measure of product thickness 

 Thicker product may reduce agitation 

 Measure consistency at location specified in 

the process schedule and in accordance with 

a written procedure 

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R 

Consistency 

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Consistency 

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Viscometer 

The spindle is immersed 

into the test liquid. The 

viscometer measures the 

additional torque required 

for the spindle to overcome 

viscous resistance and 

regain constant speed. 

This value is then 

converted to centipoise 

and displayed on the 

readout. 
 

 

 

 

Consistency 

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VISCOSITY IS 

DETERMINED 

BY HOW FAST 

THE BALL 

FALLS 

THROUGH 

THE LIQUID 

VISCOSITY IS 

DETERMINED 

BY HOW FAST 

THE LIQUID 

FLOWS 

THROUGH 

THE HOLE IN 

THE CUP 

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Retort Operation - Rotational Speed 

 Affects product agitation 

 Affects the process time 

 Specified by PA in the process schedule 

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Rotational Speed 

The rotational speed must be: 

 Checked and adjusted when the retort is 

brought up to temperature 

 Determined and recorded at least once for 

each retort load 

Notice to prevent unauthorized changes 

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Recordkeeping Requirements 

 Critical factors must be measured and 

recorded in accordance with the method and 

frequency in the written procedure 

 Must include reel speed 

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Retort Operation - Condensate Removal 

 Required to remove condensate 

 Drain open for sufficient time 

 Provide for continuous or intermittent removal 

 Bleeder arranged for observation 

 Observe and record frequently 

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Questions? 

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Questions?

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