# Presentation: 217420

## Post-Processing Interventions to Control Listeriosis

- Don L. Zink, Ph.D.
- Office of Plant and Dairy Foods and Beverages
- Center for Food Safety and Applied Nutrition
- Food and Drug Administration

## Risk Management Strategies

- Eliminate *L. monocytogenes* from the environment  of processing plants that produce ready-to-eat foods
- Use a pasteurization processes to destroy* L. monocytogenes*
- In-pack pasteurization, or
- Immediately before packaging
- Use product formulations that prevent the growth of *L. monocytogenes*

## Steam Surface Pasteurization*

**SSP module extends length by two indexes**

*** A joint development by ALKAR-RapidPak, Inc., Kraft/Oscar-Mayer and USDA-ERRC**

- Provides a surface kill step immediately before packaging
- Adapts to existing line, no effect on line speed or packaging cost

- Graphics and information provided by ALKAR-RapidPak, Inc.

## Steam Surface Pasteurization

**Top film**

**Discharge**

**Cut                        Seal                         Cool            SSP           Load            Form          Preheat**
**	****	****	****	****	****            ****heat **
**	****	****	****	****	****         ****treatment**

**SSP step = 1.5 sec of high pressure steam**

**Machine Configuration**

**Film Travel Direction**

- Graphics and information provided by ALKAR-RapidPak, Inc.

## Steam Surface Pasteurization

**Vacuum Cooling                                    Steam Injection**

**Servo lifts product pedestal up into SSP chamber **

- Graphics and information provided by ALKAR-RapidPak, Inc.

## Steam Surface Pasteurization

**Vent Condensate Ports**

**High Pressure Steam Injection**

**Bursts 1 and 3**

**Bursts 2 and 4**

- Maximum contact time on most difficult area --- ends
- 1.5 second cycle time with 4 alternating steam bursts per cycle

- Graphics and information provided by ALKAR-RapidPak, Inc.

## Steam Surface Pasteurization

- Hot dogs inoculated with indicator microorganism
- SSP treatment = 1.5 seconds
- 4-log reduction for single-layer package configuration
- Actual *Listeria monocytogenes* inoculated-pack tests (102 per package) resulted in zero positives
- Double-layer package tests in progress
- Preliminary findings show 2.0 - 2.5 log reduction

- Graphics and information provided by ALKAR-RapidPak, Inc.

## High Pressure Processing

- Data and images supplied by Dr. Peter Slade, NCFST

## High Pressure Processing

- Uses the combined effects of temperature and high pressure to kill bacteria
- Minimizes thermal damage to products
- Reduces treatment time
- Lethal effect of treatment can be modeled and characterized for each product type
- Process can be applied to packaged product
- Not limited to surface-only effects, thus is applicable to sliced products
- A Batch process with significant capital costs

- Data and images supplied by Dr. Peter Slade, NCFST

## High Pressure Processing

- -7.5

- -5.8

- -4.2

- -2.5

- -0.8

**  ****Log Reduction (N/N****0****) **

-   43.00

-   48.50

-   54.00

-   59.50

-   65.00

- 30.00

- 35.00

- 40.00

- 45.00

- 50.00

** ****Pressure**
**(MPa)****  **

**  ****Temperature °C****  **

**t = 4.0 minutes**

- Data and images supplied
- by Dr. Peter Slade, NCFST

## High Pressure Processing

| Product | Log CFU | Log N/N0 |
| --- | --- | --- |
| Untreated Control | 8.28 | 0 |
| Bologna | 4.08 | -4.20 |
| Smoked Turkey | 2.96 | -5.32 |
| Smoked Ham | 2.88 | -5.40 |

- P = 65 Kpsig (450 MPa)       T = 40°C      t = 6.0 minutes

- Data and images supplied by Dr. Peter Slade, NCFST

## In-Package Pasteurization

**Stork RMS-Protecon (Townsend) Steam-Based**
**Post-Process Pasteurization System**

- Data and images supplied by Drs. James Marsden and Randall Phebus, Kansas State University

## In Package Pasteurization

**Log cycle reduction of *****Listeria monocytogenes at 96.1°C***

- Data and images supplied by Drs. James Marsden and Randall Phebus, Kansas State University

## Product Formulation

- Weak acid.
- Disrupts  membrane pH gradients
- Inhibit energy metabolism.
- Lactate alone only bacteriostatic at high concentrations.

- Dissociates into acetic acid and sodium acetate.
- Lowers pH due to presence of acetic acid
- Sodium diacetate alone only bacteriostatic at high levels.

**Sodium or Potassium Lactate**

**Sodium Diacetate**

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

**Influence of Lactate and Moisture on Predicted Growth**
**Rate of *****L. monocytogenes***** in a Cured RTE Meat**

**Salt = 2.2 %, Diacetate = 0.1%**

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

**Potassium Lactate Syrup (%)**

**Product Moisture (%)**

**Predicted Growth Rate (wk-1)**

**2.5**

**3.5**

**4.5**

**5.5**

**6.5**

**7.5**

**55**

**59**

**63**

**67**

**71**

**75**

**0**

**0.04**

**0.08**

**0.12**

**0.16**

**0.2**

**0.24**

**Influence of Lactate and Moisture on Predicted Growth**
**Rate of *****L. monocytogenes***** in an Uncured RTE Meat**

**Salt = 2.2 %, Diacetate = 0.1%**

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

- The model has been incorporated into a spreadsheet.
- Composition (moisture, salt, lactate and diacetate) and an assumption about inoculum are input.
- Growth parameters and a predicted growth curve are generated.
- The model is used interactively to develop formulations that  predict acceptable product quality and inhibit *Listeria* growth.

**Application of Lactate – Diacetate to Cured RTE**
**Meat Products**

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

- Growth rates in uncured products are much higher
- Nitrite inhibits the growth of *Listeria*
- Rigid environmental control programs are important for both cured and uncured products

**Application of Lactate – Diacetate to Uncured RTE**
**Meat Products**

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

- Data and images supplied by Dr. Paul Hall, Kraft Foods

## Product Formulation

**Inhibition of Growth of *****L. monocytogenes***** at 4°C by**
**Buffered Sodium Citrate (Ional****TM****)**

- Data and images supplied by Drs. James Marsden and Randall Phebus, Kansas State University

**Surface inoculum on beef franks**