Keeping Listeria at Bay:The battle that ready-to-eat processors

can’t afford to lose

Host: Bill Kinross, Publisher, MeatingplaceModerator: Lisa Keefe, Editor, Meatinglace

Presenter

Harshavardhan Thippareddi,

Associate Professor of Food Science, Department of Food Science and Technology, University of Nebraska, Lincoln

Listeria Control: Old Problem, New Solutions

Harshavardhan Thippareddi, Ph. D.www.meatingplace.comSept 9, 2009Prepared by: Martin Wiedmann, Ph. D., Cornell University, Ithaca, NY

Well Known “Facts” • Human listeriosis can occur as an epidemic

or as sporadic cases• L. monocytogenes common in certain/many

environments• L. monocytogenes grows at refrigeration

temperatures• Infectious dose is high

– Growth in foods is usually needed to reach levels likely to cause human disease

Martin Wiedman, Cornell University

• Human exposure is common• Majority (ca. 99%) of human listeriosis

cases are foodborne • Potentially long incubation period (7-60

days)• Human listeriosis affects predominantly

elderly and immunocompromised people, pregnant women and newborns

Martin Wiedman, Cornell University

Well Known “Facts”

The FDA-CSFAN, USDA-FSIS, & CDC Risk Assessment – Highlights• Most human listeriosis cases in US appear to

be caused be contaminated deli meats– RTE deli meats – 1,598 cases– Pasteurized milk – 90 cases– High fat and other dairy products – 56 cases– Not-reheated frankfurters – 31 cases– Cooked ready-to-eat crustaceans – 2.8 cases– Smoked seafoods 1.3 cases– Fruits and vegetables – 1.1 cases

*FSIS results of ready-to-eat products analyzed for Listeria monocytogenes

Per

cent

Pos

itive

sPrevalence Of Listeria Monocytogenes On RTE Meat And Poultry Products*

Human Listeriosis - Trends

http://www.cdc.gov/FoodNet/factsandfigures/trends.html

Listeria Monocytogenes Prevalence(%) On RTE Meat And Poultry, 2008

http://www.fsis.usda.gov/Science/Table22_Micro_Testing_RTE_2008/index.asp

Challenges Towards Continuous Reduction Of Human Listeriosis

• LM is common throughout the food chain• A single magic bullet will not work• Focusing on one product (RTE deli meats) at

one point (processing) does not seem to work

USDA-FSIS Final Rule –RTE Processing Establishments

Establishments producing post-lethality exposed RTE product must comply with requirements included in one of the following alternatives (§430.4)Alternative 1: Use post-lethality treatment AND an antimicrobial agent or processAlternative 2: Use post-lethality treatment OR an antimicrobial agent or processAlternative 3: Use sanitation measures ONLY

Physical Post-lethality Treatments

• Heating– Steam– Submersion in hot water– Radiant oven heating

• High Pressure Processing

Thermal (Surface) Pasteurization Systems for RTE Meat Products• Meat product type and composition

– Whole muscle vs. restructured product - product surface characteristics

– Thermal properties• Product packaging

– Packaged vs. non-packaged– Film thickness and material

• Product orientation & package design– Single vs. double layer – hot dogs– Sliced product – deli type products

Single-LayerFranks

Double-LayerFranks

.75”

1.5”

Single-LayerSeparated Franks

Product Orientation Effects

Courtesy: Alkar

Turkey breastRoast beef

Ham

Product Orientation Effects

Courtesy: Alkar

Thermal (Surface) Pasteurization Systems for RTE Meat Products

• Hot water-based systems• Steam-based systems

– Non-condensing steam– Condensing saturated steam– Flash steam system

Destruction Of L. Monocytogenes Using Hot Water System

Muriana et al., 2002

High Hydrostatic Pressure Systems

• Non-thermal intervention technology• Minimal quality changes• Can be combined with other treatments such as

heat• Pressures in the range of 250 MPa (36,260 PSI)

to 600 MPa (87,023 PSI)

100 MPa=14,504 PSI

High Pressure Processing Systems

High Hydrostatic Pressure Treatment – Factors Controlling Application

• Product type and composition• Processing time and temperature• Types of microorganisms to be inactivated

High Hydrostatic Pressure Systems

High Hydrostatic Pressure Systems

Post-process Lethality Treatments – Chemical Interventions

Antimicrobial Agents – Lethality Treatments

• Acidic calcium sulfate• Acidified sodium chlorite• Peracetic acid• Lauric arginate• ε- polylysine

Antimicrobial Agents – Lethality Treatments

• Liquid smoke fractions• Listeria phages• Octanoic acid• Ozone (ozonated water)

Acidic Calcium Sulfate

Nunez et al., 2004

Acidic Calcium Sulfate

Nunez et al., 2004

Acidified Sodium Chlorite

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

0 7 14 21 28

Days of Storage

Log

CFU

/cm

2

L/D/ASC (H) L/D (H) Cont (H) L/D/ASC L/D Cont

Luchansky et al. 2006

Model System – Ε- Polylysine

Geornaras et al., 2005

Smoke Derivatives – L. Monocytogenes Control

Gedela et al. 2007

Antimicrobial Agents – Control Lm Growth

Organic Acids Salts

• Approved for meat product use– Sodium or Potassium salts of lactic acid– Sodium acetate or diacetate– Sodium citrate buffered with citric acid to

pH 5.6• Live bacteria – Canbiocin• Levulinate (not commercialized yet)

Synergism – Lactate and Diacetate

0.0

1.0

2.0

3.0

4.0

5.0

Antimicrobial

Log C

FU/g 2.5 SL

0.1 SDA0.2 SDA2.5 SL + 0.1 SDA 2.5 SL + 0.2 SDA

Control Of Listeria Monocytogenes In Taco Meat (Aerobic)

2.03.04.05.06.07.0

0 3 7

Days at 10 C

Log C

FU/g

CI 1I 1.3I 2.5IP 1IP 1.3IP 2.5Opti 2.5

Acknowledgments

This Project was funded through a grant from the National Integrated Food Safety Initiative (Special

emphasis grant No. 2005-51110-03278) of the Cooperative State Research, Education and Extension Service, U. S. Dept. of Agriculture

Presenter

John N. Butts, Vice President of

Research,Land O’ Frost

Data Analysis, Investigation and Corrective Action

“Follow the data trail to the source but always be alert and aware to the organism’s ubiquitous presence and pervasive nature.”

John ButtsLand O’ FrostMeatingplace WebinarSept 2009

Commitment Model

• Resistant – don’t believe it has value• Accepting – why not• “Buy-in” – we will do it• Engagement – involved in solution• Commitment – hold self and others

accountable for achieving results

FSIS Regulatory Testing for Lm in RTE Products by Calendar Year 1990-2007

(All Years All Projects)

4.61%

4.03%

3.61%3.44%

2.90% 3.02% 2.91%

2.25%2.54%

1.91%

1.45% 1.32%1.03%

0.76%0.55% 0.64% 0.61%

0.43%

0.0%

0.5%

1.0%

1.5%

2.0%2.5%

3.0%

3.5%

4.0%

4.5%

5.0%

1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

Calendar Year

Perc

ent P

ositi

ve

Incidence of Foodborne Illness 1996-2007: Listeria*

0

0.1

0.2

0.3

0.4

0.5

0.6

1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007

National Health Objective: .25

Inci

denc

e pe

r 100

,000

Pop

ulat

ion

*Preliminary FoodNet Data on the Incidence of Infection with Pathogens Transmitted Commonly Through Food --- 10 states, 2007

Sources of Ls in High-Risk RTE Area• Transferred from Zone 4 area outside of the

High-Risk RTE area– Homeless, but looking for a harborage location – Typically found with a transfer point monitoring

positive• Growth niches within High-Risk RTE area

1. This means they are established, and have found a protective home in equipment or facility.

2. They may exist in a transient home such as rework pans, trash containers or other difficult to clean mobile container / environment.

Transfer Points vs Niches

Many positive sites found during monitoring are not growth niches. They are transfer points (i.e., a product handler’s gloved hands, floor sample in high traffic pathway).

Transfer points are not growth niches because the organism is eliminated during the cleaning and sanitizing

process.

Growth NichesLocations harboring the organism after the routine sanitation process for that area has been completed.Examples

– Hollow roller on conveyor transporting food product

• Hollow rollers not disassembled cleaned and sanitized or heat treated in a manner to eliminate any contaminating organisms can become growth niches.

Hollow roller with solid stainless steel shaft in center (almost press fit).When center shaft removed organic matter is evident.

Growth NichesGrowth Niches

Growth NichesMust either be designed out of the system or managed as a part of the process.• Design Examples

– Equipment is redesigned to eliminate or seal hollow areas

• Hollow areas of equipment (e.g., frames, rollers) must be eliminated where possible or permanently sealed (caulking not acceptable). Bolts, studs, mounting plates, brackets, junction boxes, name plates, end caps, sleeves and other such items must be continuously welded to the surface of the equipment and not attached via drilled and tapped holes.

AMI Equipment Design Task Force

Growth Niches

Minimize with process control techniques• The potential to support growth still exists

within the machine, part or area» Whenever this becomes the chosen path remember

to implement methods that will hold the gains with turnover in both hourly and management ranks.

Growth Niches

• Examples of how to minimize with process control techniques– Disassemble clean and sanitize– Heat sanitize

• Cook in oven or smokehouse• Cover with tarp and inject steam• Place in COP tank

Equipment at End of Production

Hand Clean & Sanitize. Parts to COP

Hand Clean & Sanitize, Small Parts to COP and

Large Parts to Smokehouse

Pasteurize

Intensive level

Normal level

Sanitation Process Control Steps Necessary for Effective Control of Complex Equipment

Disassemble

Disassemble

To a greater level

Predefined Interval based

on need

Cooking level

Disass

emble

To con

trol c

old sp

ot

Predefined Interval based

on need

Clean & Sanitize

Clean & Sanitize

Clean & Sanitize

Routine / Daily

Equipment at End of Production

Hand Clean & Sanitize. Parts to COP

Hand Clean & Sanitize, Small Parts to COP and

Large Parts to Smokehouse

Pasteurize

Intensive Level Degree of

Disassembly

Normal Level Degree of

Disassembly

Sanitation Process Control Steps Necessary for Effective Control of Complex Equipment

Predefined Interval based

on need

Cooking Level Degree of

Disassembly

Predefined Interval based

on need

Clean & Sanitize

Clean & Sanitize

Clean & Sanitize

Routine / Daily

Critical Factor

Critical Factor

Critical Factor

Critical Factor

Critical Factor

Critical Factor

Normal cleaning and sanitatio

n

Observe assembly

Seek and Destroy Process

Observe Post assembly sanitizer application

Observe flood sanitization

Disassemble to normal daily sanitation level

Inspect and swab any suspect areas

Disassemble any remaining machine components

Observe normal setup and start up activities

Stop operation before product is placed on the line

If APC growth is supported then the suspect area is a potential

growth niche

If area is Ls positive then it is a growth niche

Are cleaning methods

acceptable?

Is degree of disassembly acceptable?

Are all parts and components being

adequately sanitized (chemical

or heat)?

Clean and flood or heat sanitize all disassembled line components

Are GMP's followed?

Evidence of unacceptable

organic buildup?

Process 1

Process 2

Process 3

Process 4

Operator tools Line workers

Maintenance

Product transport

MaterialsSample everything coming to line

~

A Time Study consists of sampling the line components and every thing that comes to the line over a period of time

The Time Study typically starts during

setup and assembly . Samples will be taken

as workers and product come to the line, repeated after line is running then

every 2 hrs thereafter

Time Study Locating a Transfer Vector

Swat Team Sampling

• Sample during an idle period after sanitation, before production i.e. Saturday when no production is running

• Sample large areas using sponges or gauze.• Sample areas not typically sampled during

routine sampling– We found a transient growth niche using this method

– COP basket handle

Presenter

Mike DeSmet, Vice President of

Food Safety,West Liberty Foods

Listeria Defense:A Multi-Hurdle Approach

• There is no one magic bullet.• There is no one department responsible.• Attitude must start from the top one down.• For every one dollar spent up front, multiple

dollars are saved later.• No one is immune.

Scope: It Takes More Than One

• Building Design/Physical Barriers• Chemical Interventions• Preventive Programs• Product Design/Handling• Training• Verification Activities

Multiple Hurdle Approach

• Each product slicing cell has separate positive pressure, air handling system.

• HEPA air filtering systems keep with our clean room focus.

• Separate slicing cells prevent cross contamination.

• Encapsulated suits to prevent cross contamination from employees.

Building Design/Physical Barriers

• Separate drain system in each slicing cell with capability of back flooding each drain system.

• Ceilings, floors and walls are designed for easy cleaning and sanitizing.

• Exposed product production areas are targeted to <38°F.

• Design eliminates cardboard and wood from entering exposed product areas.

Building Design/Physical Barriers

• Foamers/bootwashes• Sanitizer challenge studies• Rotating Sanitizers• Equipment Fogging• Choosing the correct cleaners and sanitizers for

your equipment, your environment and the organism.

Chemical Interventions

• Equipment audits/repair• Deep cleaning programs (see next 2 slides for

examples)• Use of indicator organisms to identify potential

niches• GMP audits• Maintenance PM’s• Maintenance Tool Cleaning

Preventive Programs

Operator Side Spindle CoverAssembled Dissembled

When removed this cover exposed the spindle to allow for cleaning. This cover is removed and cleaned with a Solvaxx solution once a week.

coverCover removed

Flip Flop Electrical CabinetOperator side Non-operator side

These cabinets are opened up and inspected weekly. These areas can be carefully cleaned with a Wypall lightly saturated with isopropyl alcohol by a qualified member of the maintenance department.

• Proper Cooking• Antimicrobial Ingredients• Modified Atmosphere Packaging• Freezing• Shelf Life Determination• Temperature Control (cold chain management)

Product Design/Handling

• Partnered with Iowa State• Use of Visual Aids• Food Safety Certification as a pre-hire concept• GAP Training (Getting Acquainted Period)

successive classes throughout the first 90 days• Annual Re-training

Training

• Strong Listeria program• >3500 Listeria species swabs per month

company wide• Zone 1 (conveyors, slicers, product beds)• Zone 2 – indirect contact (on off buttons,

framework, etc.)

Verification Activities

• Zone 3 environmental (floors, ceilings walls)• Zone 4 adjacent to RTE areas (employee welfare

areas, hallways, dry storage)• Every line, every week• Random product sampling• Rapid detection methods

Verification Activities

• The listeria control system is a never ending process.

• Constant changes due to continuous education, extensive training and monitoring processes.

• Watching for new technology.• Utilize Trade organizations as valuable resource

for latest topics and technical expertise.• Utilize your chemical representatives and

equipment representatives.

It Never Ends

• Growing concept that Food Safety is not proprietary.

• When one company stumbles we are all affected in the eyes of the consumer.

• WLF and IA State teamed up to sponsor a food safety conference to share our training program with everyone.

Sharing Technology

Questions & Answers

For More InformationHarshavardhan Thippareddi: hthippareddi2@unlnotes.unl.edu

John N. Butts: John.Butts@landofrost.comMike DeSmet: Mike.DeSmet@wlfoods.com

Bill Kinross: bkinross@meatingplace.comLisa M. Keefe: lkeefe@meatingplace.com

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