Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 MECHANICS OF CHILLING RTE MEAT PRODUCTS Seth Pulsfus Alkar Technical Development Better be completely safe…

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Brine Chiller

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Fast chilling delivers safer RTE products Non cured meats –From 130 to 80  F  1.5 hr; then from 80 to 40  F  5 hr Or –From 120 to 55 o F  6 hr; continue until 40  F Cured meats –From 130 to 80  F  5 hr; then from 80 to 45  F  10 hr Requirements to stabilize heat-treated meat and poultry products Appendix B objective: prevent the growth of spore-forming bacteria (Clostridia)

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Fast chilling offers other benefits to your operations Prevent deterioration of products characteristics Improve production output –Reduce water evaporation due to slow cooling (shrink)  Improve cooking yields – Reduce cooking yields variation –Improve slicing and peeling performances  Reduce re-work and “tankage” Improve operating costs –Reduce in-process inventory  Increase production output  Optimize floor space utilization –Increase energy efficiency

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Purpose of this presentation Review the parameters affecting the chilling process Describe the different equipment utilized to chill RTE meat products Explain how to evaluate chilling processes in regard to Appendix B

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Validation of Chilling Processes Chilling Equipment Design Chilling Process Parameters OUTLINE

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Chilling involves a 2-stage heat transfer 1- Heat migrates from the product center to the surface  conduction Product cross-section Transfer speed depends on product’s characteristics 2- Heat transfers from the surface to the cooling medium  convection Product cross-section Transfer speed depends on medium’s characteristics

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Product’s “heat transfer” properties are characterized by 4 physical variables Specific heat (Cp) = related to product molecular structure  characterize how easy it is to change product’s temperature Thermal conductivity (k) = speed of heat transfer  Affected by product’s moisture content: water conducts heat better than fat Latent heat = energy required to change phase i.e. to freeze the product Product’s geometrical shape  The thicker the product, the longer the chilling

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Freezing Latent heat is a critical variable when fast chilling large pieces Use of very cold medium  crust freezing During freezing product’s temperature does not decrease = change of phase from water to ice  High energy requirement  Use of “equilibration” step when chilling

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Example: freezing of Ground Turkey chubs 10 lb chubs, 4.3” diameter, -10 F. Glycol Time (hours) Period of Latent Heat Glycol Product Core

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Example: crust freezing and equilibration process

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 % Solids % Water Cp k Latent Heat Bacon Bologna Franks Ham Turkey Thermal Properties of Meat Products (kJ/kg. °C) (W/m. °C)(kJ/kg)

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Chilling media are characterized by their heat transfer coefficient Method Coefficient (W/m 2. K) Air - Free convection Forced convection Liquid - Free convection Forced convection ,000

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Validation of Chilling Processes Chilling Process Parameters OUTLINE Chilling Equipment Design Product thermal characteristics and shape Heat transfer coefficient  medium, method

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Holding Cooler: free air convection

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 High-Performance Air Chiller: forced air convection Heat exchanger Exhaust

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Brine chiller: forced liquid convection Brine receptor tank Heat exchanger Brine shower Storage tank

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Chilling efficiency: Brine > Blast > Cooler 7# Pressed Ham, 10” x 6” x 3.5” Temperature (F) Time (hours)

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 The choice of chilling equipment depends on products characteristics, processes,… Strengths Lower initial cost Ease of maintenance Simplicity of design Weaknesses Inefficiency of air Longer cooling time Less uniform Higher shrink Strengths High Efficiency Less than 1% shrink Faster chill time (vs. cooler) Energy savings (vs. cooler) Product compatibility Weaknesses Higher initial cost Longer chill time (vs. brine) More floor space (vs. brine) Maintenance (vs. cooler) Air chillingAir blast chilling

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 And operation capabilities Strengths High efficiency % faster 0% shrink Less floor space % less energy Reduced inventory Weaknesses Higher initial cost Maintenance / cleaning Cost of solution Brine disposal Product compatibility Brine Low cost Most products Limited life 0°F minimum Corrosive Glycol High cost Impervious casings Indefinite life; > 25% glycol = bactericidal -20°F minimum Non-corrosive Absorbs moisture Less prevention Liquid chilling Brine or glycol?

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Chilling Process Parameters Chilling Equipment Design OUTLINE Validation of Chilling Processes Product thermal characteristics and shape Heat transfer coefficient  medium, method Chilling efficiency: brine > blast > holding cooler Choice depends on products, processes, operation capabilities

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Using a “safe harbor” chilling process whenever possible makes life easier Comply with FSIS stabilization Performance Standards  Time/temperature records will do Customize a chilling process  Use literature or peer reviewed methods Or  Conduct challenge studies using C. perfringens as model

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 How to analyze a chilling process record Does this chill pass? Method ° to 80°F in 1.5 hr 80° to 40°F in 5 hr Method ° to 55°F in 6 hr Continue to 40°F It does! Method 1

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 How to analyze a chilling process record Does this chill pass? Method ° to 80°F in 1.5 hr 80° to 40°F in 5 hr Method ° to 55°F in 6 hr Continue to 40°F It does! Method 1

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 How to analyze a chilling process record Does this chill pass? Method ° to 80°F in 1.5 hr 80° to 40°F in 5 hr Method ° to 55°F in 6 hr Continue to 40°F It does! M1 for brine 25  F M2 for air 12  F

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 Chilling Process Parameters Chilling Equipment Design SUMMARY Validation of Chilling Processes Product thermal characteristics and shape Heat transfer coefficient  medium, method Chilling efficiency: brine > blast > holding cooler Choice depends on products, processes, operation capabilities Use “safe harbor” processes Analyze chill curve

Thermal Processing of RTE Meat Products The Ohio State University March 28-30, 2006 MECHANICS OF CHILLING RTE MEAT PRODUCTS Alkar Technical Development Better be completely safe…