antimicrobial agents to control listeria monocytogenes ... · antimicrobial agents to control...

Antimicrobial Agents to Control Listeria monocytogenes Listeria monocytogenes.

A d L Milk ki PhDAndrew L Milkowski PhDAdjunct ProfessorMuscle Biology LaboratoryUniversity of Wisconsin - Madison

Food Research InstituteUniversity of Wisconsin-Madison

TopicsWhy use antimicrobials

Topics

Lactate/Diacetate

Antimycotics

Newer technologiesNewer technologies

Final thoughts


Preservative Methods to Reduce Foodborne

Prevent inadvertent contamination

Pathogen Risk*

Removal of contamination

• Thermal destruction by cooking

• Surface treatments at packaging

• Post-package pasteurization treatments

Inhibit G o thInhibit Growth* Adapted from Sofos, et al., 1998


What happens with no growth i hibit d L t i tiinhibitors and Lm contamination

Turkey Breast at 4CHam at 4C1.6% Salt, 75% Moisture, Sodium TripolyphosphatepH 6.2

2.5% Salt, 75% Moisture, Sodium TripolyphosphatepH 6.2


How can we inhibit growth of L t g i RTE t ?L. monocytogenes in RTE meats?

Extend the lag-phase or diminish the rate during log-phase of growth g g p g

Cured meatsNit it k th ff t i• Nitrite makes the effort easier

Uncured meatsUncured meats• More difficult to achieve


Lactate and Diacetate

• Most widely used Lm growth inhibitors in the US

• ~ 70% of RTE cured meats use this approach


Sodium and Potassium LactateSodium and Potassium Lactate

Weak acidsProduced from fermentation of sugarUsage level of 2 - 4% (of 60% solution) Slight salty flavorDis pts bacte ial memb ane pH g adients Disrupts bacterial membrane pH gradients Inhibits energy metabolismAntibotulinal agent Antibotulinal agent


Sodium DiacetateSodium Diacetate

Half neutralized vinegar a eut a ed egaDissociates into 40% acetic acid and 60% sodium acetateLower product pH due to presence of acetic acidU l l 0 10 0 15%Usage levels, 0.10 - 0.15%


Wh i bi ti d d?Lactate salts alone are only bacteriostatic

Why is a combination needed?y

at high concentrations (>3-4%)• Flavor quality impacted• Sodium?

S d d l lSodium diacetate alone only is bacteriostatic at high concentrations

Product stability impacted purge texture• Product stability impacted - purge, texture• Flavor quality impacted• Legal maximum in U S is 0 25%


• Legal maximum in U.S. is 0.25%

The Purac Opti Form® ModelDeveloped in 2001-2002

The Purac Opti.Form® Modelp

• Growth model• Factors – Salt, Product Moisture, Lactate, Diacetate• No cured model• No cured model

Updated in 2003• Boundary “time to failure” presentation

Refined – Expanded in 2007• Returned to a growth model

Added pH and temperature as inputs• Added pH and temperature as inputs• Includes cured and uncured predictions


Two Ham Scenarios at 4C Storage

2.5% Salt, 75% Moisture,2% Potassium Lactate14% sodium diacetate sodium tripolyphosphate.14% sodium diacetate, sodium tripolyphosphate

pH 6.2

2.5% Salt, 75% Moisture,2% Potassium Lactate.14% sodium diacetate, pH 5 8 pH 5.8


Two Uncured Turkey Breast Scenarios at Breast Scenarios at 4C Storage

1.6% Salt, 75% Moisture,2% Potassium Lactate14% Sodium Diacetate Sodium Tripolyphosphate.14% Sodium Diacetate, Sodium Tripolyphosphate

pH 6.2

1.6% Salt, 75% Moisture,2% Potassium Lactate.14% Sodium Diacetate, pH 5 8 pH 5.8


Ad t g f L t t /Di t tAdvantages of Lactate/DiacetateProven effective and reliableProven effective and reliableEasy to verifyRelative low costRelative low costTested with consumers and widely acceptedacceptedProtects vs. risk of contamination by consumer after package is openedconsumer after package is opened


Antimycotics•Benzoate

Antimycotics•Benzoate•SorbateP i t •Propionate


Control of Listeria on Cured Ham stored at 4°C (2.2% NaCl whole; 156 ppm nitrite, 75% moisture)

5Control

3

4

g C

FU/g

)

Na Benzoate 0.1%Na Propionate 0.2%K Sorbate 0.3%K Lactate 1.6% + Na Diacetate 0.1%

2

3

f Lis

teri

a (lo

g

0

1

Gro

wth

of

-12 4 6 8 10 12

C


15

Weeks at 4C Glass, et al, JFP 2007

Effect of benzoate, moisture, NaCl, Di t t L i d RTE tDiacetate on Lm in cured RTE meats

2.0% NaCl0.1% Na Diacetate

Seman et al., 2008 JFP 71:1386


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Differences from Glass et al, extended testing time to 18 wks; decrease NaCl

Other antimicrobialsFermentation & Fermentation Blends

Other antimicrobialsFermentation & Fermentation Blends• Danisco – MicroGARD™, NovaGARD™

• Kemin - SHIELD®

• Kerry – Alta®

• Purac - Verdad®

• WTI - Ional ®


Uncured Turkey Listeria Testing3.5 % VERDAD NV55 controls Listeria for 80 daysCompared to 26 days for Opti.Form PD4

8.09.0

10.0

6.07.0

2 log growth5.0

2.03.04.0

0 10 20 30 40 50 60 70 80 900 10 20 30 40 50 60 70 80 90

Days at 39°F/4°C

Control 2.5% Opti.Form PD4


3.5% Verdad NV55 4.5% Verdad NV55

Source: Courtesy of Purac America

Frankfurter Listeria TestingEffect of Verdad NV15 and NV55 on Listeria monocytogenes inEffect of Verdad NV15 and NV55 on Listeria monocytogenes in

frankfurter

7.00

5.00

6.00

g

2 00

3.00

4.00

Log

CFU

/g

0.00

1.00

2.00

0 20 40 60 80 100 120

Control 2% Verdad NV15 3% Verdad NV15

2% Optiform PD4 2% Verdad NV55 3% Verdad NV55


2% Optiform PD4 2% Verdad NV55 3% Verdad NV55

Source: Courtesy of Purac America

Surface Applied AgentsFlexibility

Surface Applied Agents

• Low Levels• Multiple possibilities

o Organic Acids, Spice Extracts, Bacteriocins Lauric Arginate…..

Equipment is available• USDA’s SLIC™ concept• RapidPak™ suface application during packagingp pp g p g g• Capital costs?

May help achieve Alternative 1 statusRequires ongoing verification/validationRequires ongoing verification/validationNot easy to do on sliced products• Slicing speed• Surface area to cover


Surface area to cover

Resources for InformationAcademia

Resources for InformationAcademiaSuppliersUSDA Directive 7120 1USDA Directive 7120.1FDA GRAS notices• http://www accessdata fda gov/scripts/fcn/fcn• http://www.accessdata.fda.gov/scripts/fcn/fcn

Navigation.cfm?rpt=grasListing


Lm Growth Inhibitors, Regulations d P bli H lthand Public Health

Do not change likelihood of Listeria Do not change likelihood of Listeria contamination in products

Do not kill Listeria

By inhibiting growth expect less likelihood of related Listeriosis of related Listeriosis


Listeria Growth InhibitionListeria Growth Inhibition

8.00

Predicted Log Counts/gm

Listeria Growth InhibitionEstimated Benefit to Public Health*

Listeria Growth InhibitionEstimated Benefit to Public Health*

7.001/7,500 risk

5.00

6.00

3.00

4.00

1/75 MM risk

1.00

2.00

1/50 B risk


*Based on Growth Model for 50 gm of RTE cured processed meat and median mortality riskfor neonates published by FDA/USDA Fall 2003 Listeria monocytogenesRisk Table IV-12 and Figure IV-7

SummarySummaryEnvironmental monitoring and preventative

i t i t ti h equipment interventions or process changes that minimize contamination in finished product

PLUS

Listeria Growth inhibitors in productListeria Growth inhibitors in product

EQUALSQ

Effective reduction in Lm risk


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antimicrobial agents to control listeria monocytogenes ... · antimicrobial agents to control...

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