Part 4: Corrective Actions

Lisa OlsenSpecialist Adviser, NZ Standards

What should you get from this guide?

•A clearer understanding of MAF’s expectations if there is a Listeria contamination event

•Information which can be used to develop your LMP and help you prepare for a contamination event

• Contaminated product means product that testing has shown to be contaminated with L. monocytogenes.

• At risk product means all batches of product that are potentially contaminated with L. monocytogenes

• Contamination event is when Listeria and/or L. mono are detected on product contact surfaces and/or in product during routine monitoring, surveys or an illness investigation.

Definitions

How might you receive a Listeria Notification?

•Routine environmental monitoring•Routine product testing•Customer sampling•Regulatory surveys•Illness investigations

Corrective Actions

•Halt processing•Isolate affected equipment and areas•Notify verifier, Food Act Officer or MAF within one working day of notification

Corrective Actions

•Retrieve or recall contaminated and at risk product•Identify and hold contaminated and at risk product

Investigate Cause of Contamination

•Inspect contaminated process area(s) and equipment•Carry out investigative environmental sampling to identify any environmental contamination source

Investigative environmental sampling

•Commence within 1 working day of receiving notification•Explore all possible areas of contamination rather than focus on small areas•Review environmental results from other areas to identify areas that may require reassessment of controls•Testing at higher level should continue until source of contamination identified•Thoroughly clean and sanitise once sampling completed

Investigate cause of Contamination

•Review supporting system and processing records•Sample raw and in-process materials•There is a good chance that more than one thing is the source of problem – it is quite likely to be a combination of things – keep an open mind

Clean and sanitise

•In a high proportion of cases where Listeria contamination occurs there have been problems with the cleaning and sanitising programme•A person with the appropriate level of expertise should be involved in any review of the programme.

Intensive Microbiological Sampling Programme

•Testing of at risk product and product contact surfaces at a higher frequency than routine microbiological monitoring•Purpose:

• identify any at risk product that may have been contaminated at time of L. mono detection

• test at risk product and product contact surfaces once processing resumes.

What product could be at risk?

Last clear test from routine monitoring

0 2 1

Lab result – L. monocytogenes detected on a sample taken at day 0

Routine monitoring, positive L. monocytogenes

Previously processed product

Days

P P P P PC

P PC

P PC

P PC

P

3 5 6 7

P P P PSamples

P = product sample PC = product contact surface sample

4

Testing at risk product: around time of the contamination event

•What product could be considered at risk? • since last not-detected result for Listeria species • on same processing line • on same day or day before the positive result • between taking the positive sample and notification of Lm• on processing lines close to contaminated line • processed under abnormal conditions e.g. failure at a CCP

How can you narrow the range of at risk product?

• Process and supporting system records • results from past testing • results from environmental investigation (if

available) • knowledge of process flow and production

schedules

At risk product:around time of contamination event

PCS positive: sample size per batch of at risk product

Product positive: sample size per batch of at risk product

Sample type Low risk Medium risk High risk

Product n=5 n=5 n=5

Sample type Low risk Medium risk High risk

Product n=5 n=30 n=60

Testing once processing resumes

•Use results of investigation to date to narrow the range of at risk product•Sample at risk product during processing based on random times or hourly•Sample product and product contact surfaces at the same time •For product with a short shelf life testing may need to occur on trial batches

Testing of at risk product and PCS once processing resumes

PCS positive: sample size per batch of at risk product

Product positive: sample size per batch of at risk product

Sample type Low risk Medium risk High risk

Product n=5 n=5 n=5PCS n=5 n=5 n=5

Sample type Low risk Medium risk High risk

Product n=5 n=30 n=60

PCS n=5 n=5 n=5

Intensive Microbiological Verification

•Commences after 3 days of “not-detected” for Listeria at intensive sampling size•Continue for 4 days to give confidence that Listeria has been controlled•Minimum suggested sample sizes given•If a positive returned, resume intensive sampling

Continued Detections?

•Response to be escalated•Usually indicate bigger more persistent problems•Halt processing on the contaminated line(s)•Engage external expert to review actions and assist in resolution•Where processing continues, all affected product at risk •Consider expanded recall•Continue investigation into cause

Sample sizes

•Suggestions only but justification expected where smaller sample sizes taken•As number of samples decrease, chance of accepting an unacceptable product batch increases. •Costs involved in sampling and testing weighed against impact of making an incorrect decision•Regulator to be involved in decisions on sample size

Micro Testing

•For product that will not support the growth of Listeria and that has a limit of 100 cfu/g, having the laboratory enumerate the Listeria could be used to assist in determining product disposition •Lm may be further differentiated to help to determine whether the same or a new type of Lm is contaminating product contact surfaces and/or the product. •By comparing the different DNA patterns you can see if:

• there is a recurring ‘house’ Lm which will have established itself in a niche or harbourage site or

• there are different DNA fingerprints of Lm it suggests that contamination is being introduced, e.g. from the external environment, ingredients, equipment, personnel.

Corrective Actions

•Dispose of contaminated and at risk product•Prevention of recurrence and review of LMP after the event•Documentation, records and reporting

Thank you