Listeria sampling concerns raised in FVO audit

Sampling for Listeria monocytogenes after cleaning in Denmark undermines the sensitivity of testing of processing areas and equipment, according to a Food and Veterinary Office (FVO) audit.

Further risk based official control sampling after positive samples is necessary to enhance official controls, said the agency.

Danish Veterinary and Food Administration (DVFA) guidelines state sampling should be done during production and/or after cleaning.

The FVO audit team also identified weaknesses in hazard analysis and procedures to avoid cross-contamination in several sites including those producing ready to eat products.

Listeria caused 40 cases and 17 deaths last year from a type of meat, known as ‘Rullepoelse’ which was traced back to Jørn A. Rullepølser in Hedehusene.

DVFA response to audit findings

The DVFA said the approach to official microbiological control is risk based.

“The DVFA has initiated a new system to enhance a uniform follow up upon laboratory results which ensures fast and accurate follow up in a uniform way,” said the agency.

“The specific matter of sampling of further products after positive official samples is handled in the context of “The Critical Review on the Danish Listeria monocytogenes effort”.

“Procedures for follow up by the CA in case of withdrawal of foodstuffs and foodborne outbreaks will be reviewed. The review will include in which cases official sampling should be performed.”

The FVO audit team noted there was a delay of three weeks in initiation of official sampling after the match of a Listeria monocytogenes outbreak to a meat producer.

In a review of the handling of the outbreak investigation the competent authority acknowledged that this delay was not justified.

“The CA identified a positive Listeria monocytogenes in a ready to eat meat product which resulted in a recall of the involved product. The CA follow up of this case did not include further official sampling of other products produced in the same establishment,” said the FVO.

“The CA stated that this is not envisaged in the procedures in place. The Danish authorities, through genome-sequencing were able to link the positive official sample to a Listeria monocytogenes outbreak that resulted in 17 deaths.”

The last audit concerning the safety of food of animal origin (mammals) in Denmark was from 19 to 29 January 2010.

In response to findings from this audit, national guidelines were updated and came into force in November 2014 – however, the FVO could not assess implementation of the changes in its December audit.  

In meat product establishments, processing areas and equipment were sampled for Listeria monocytogenes after cleaning.

When to do sampling

The EURL Lm guidelines on this establish that, to increase the probability of detecting persistent strains, sampling should be done during or at the end of production.

In the large meat product establishment visited positive Listeria monocytogenes samples in areas coming in contact with ready to eat product were documented after cleaning. In one case the corrective action was delayed by 11 days.

“The updated version of the guideline on microbiological criteria…states that samples must be taken in the food processing area and equipment under production and/or after cleaning and it is emphasized that sampling under production  should be the chosen approach if the purpose is to reveal contamination with Listeria,” said DVFA.

The DVFA said it will organise a sampling project in autumn/winter 2015 with focus on sampling the processing area and equipment to enhance focus on the matter.

Due to a political agreement to reduce documentation burden on food business operators (FBOs) the competent authority does not require they have a documented prerequisite programme.

Prerequisites that do not require documentation include cleaning, maintenance, pest control, training, personal hygiene and intake controls of incoming goods (only documented temperature controls need to be kept and storing temperature records).

Documented procedures preventing cross contamination, traceability and product recall must be available.