microbiological criteria - an introduction jens kirk andersen the national food institute technical...

Microbiological criteria- an introduction

Jens Kirk AndersenThe National Food InstituteTechnical University of Denmark

2 DTU Food, Technical University of Denmark

No of human cases in Denmark:


•Sampling•Testing•Made decision on the result


4 pages that changed the world:

1997:


Microbiological Criterion (Codex, 1997) :

A criterion defining the acceptability of a product or a food lot, based on the absence or presence, or number of microorganisms including parasites, and/or quantity of their toxins/metabolites, per unit(s) of mass, volume, area or lot


Microbiological criterium consists of:

•The microorganism•Analytical method•Sampling plan•Acceptable limit/limits•The food for which the criterion applies•The place in the food chain where it applies•Action on failure to meet the criterion

Codex, 1997


Codex, 1997:

•Food safety is assured by GHP and HACCP

•Microbiological criteria should be based on science

•Developed in a transparent fashion

•Meet the requirements for fair trade

•Setting of Microbiological Criteria is a Risk Management task


Risk Analysis

RiskAssessment

RiskManagement

ScientificIndependentUnemotional“Ivory tower”

PragmaticPossiblePoliticalPolicyTake decision


Application of MC (Codex, 1997):

•Where no other more effective tools are available

•When they are expected to improve the degree of protection offered to the consumer


Sampling uncertainty

“Even if you search you shall not always find”


Sample size 1%

contaminated

5%

contaminated

10%

contaminated

5 0.95 0.77 0.59

10 0.90 0.60 0.35

15 0.86 0.46 0.21

20 0.82 0.36 0.12

30 0.74 0.21 0.04

40 0.67 0.13 0.01

50 0.61 0.08 0.01

Possibility of accepting a contaminated lot:


No of samples, to document ”absence” ?

Def.: ”prescence below 1% at 95% probability”

Bacth size No of sample units

1- 60 all151 - 175 135276 - 360 190651 - 1000 2502001 - 3000 290


Guarantee - Zero tolerance?

•Not possible–We cannot test everything

•Not realistic–We need to eat

•Not necessary–Pathogens in low levels may be acceptable


The purpose of an MC is to reduce the risk of the consumer

Step 1: Hygiene-based MC- Hygiene parameter, E. coli, TVC

etc.

Step 2: Hazard-based MC- Pathogenic microorganisms

Step 3: Risk-based MC- Directly (mathematically) related

to consumer risk – outcome

3 steps to heaven:


•Proces Hygiene criteria

–Hygiene parameters–3-class plans–Reaction: Improvement of hygiene + review of

HACCP

EU microbiological criteria


Example:Process hygiene criteria (EU legislation)

Foodcategory

Micro-organism

Sampling plan Limits Analytical method

Stage where MC applies

Action if non-complient

n c m M

Minced meat

Aerobic plate count

5 2 5*105 5*106 ISO 4833End of manufacture

Improvement of GMP + raw materials

Entero-bacteriaceae

5 2 50 500 ISO 16649End of manufacture


Mechanically separated meat

Aerobic plate count

5 2 5*105 5*106 ISO 4833End of manufacture



EU microbiological criteria

•Food safety criteria

–Pathogenic microorganisms–2-class plans–Dramatic reaction when non-complience:

• Withdrawal• Recall


Microbiological criteria for RTE foods in which growth of L. monocytogenes will not occur

n c m M Class Plan

Listeria monocytogenes

5 0 100 cfu/g a

NA 2 b

[a This criterion is based on the use of the ISO 11290-2 method. A 25 g sample unit is taken, diluted in 225 ml and homogenized. Duplicate 1 ml portions of this 1:10 dilution of a 25 g sample unit are divided equally onto three standard agar plates (90 mm diameter) or one big agar plate (140 mm diameter) and plated. Thus, two replicate analytical portions of 0.1 g are plated for each original 25-g sample.] Other methods that provide equivalent sensitivity, reproducibility, and reliability can be employed if they have been appropriately validated. National governments should provide guidance on how samples should be collected and handled, and the degree to which compositing of samples can be employed. [b This sampling plan would provide 95% confidence that a lot of food containing an average concentration of 93.3 cfu/g and an analytical standard deviation of 0.25 log cfu/g would be detected and rejected based on any of the five samples being positive for L. monocytogenes.]


Towards a risk-based approach:

•Work has been going on for several years

•The risk-based angle is being used increasingly in Codex Food Hygiene Committee


•There must be a link between the level of hazard in a food, and the risk for the consumer

•Therefore it should be possible to translate the level of protection to a microbiological criterion


ALOP, the Appropriate Level of Protection:

The level of protection deemed appropriate by the Member establishing a sanitary or phytosanitary measure to protect human, animal or plant life or health within its territory (Definition by WTO 1995)


FSO, Food Safety Objective:

The maximum frequency and/or concentration of a hazard in a food at the time of consumption that provides or contributes to the appropriate level of protection (ALOP)

(Definition: CAC 2007)


PO, Performance Objective:

The maximum frequency and/or concentration of a hazard in a food at a specified step in the food chain before the time of consumption that provides, or contributes to, an FSO or ALOP as appropriate

(Definition: CAC 2007)


The missing link:

•The transition from Performance Objective to Microbiological Criterion?

•Two examples on how to do this will be presented at this WG!


The construction of these parameters form a “cascade” with the ALOP at the top, describing what we are trying to achieve.

ALOPHuman

PO

PO

Food Chain

FSOMeal/RTE

MC

MC


Alternative approach

The principle is simple:

1. Take a sample2. Do the testing3. Perform a risk assessment on the result4. Compare the risk to the average (baseline) risk5. Acceptability of the food is conditioned on the

relative risk

An example on this approach is also being presented at this meeting

28 DTU Food, Technical University of DenmarkThank you for your attention

microbiological criteria - an introduction jens kirk andersen the national food institute technical...

Documents

dtu food

food lot

lot of food

food chain

lot slide

consumer slide

decision slide

acceptable slide