Efficient production of mould-free dry cured lamb ribs (pinnekjøtt) and other dry cured meat products

In 2013, 200 tons of Pinnekjøtt had to be withdrawn from the market due to mould growth on the product. To increase the knowledge about problem moulds in the production of pinnekjøtt and cured meat products and to identify infection sources and problem areas as well as to find effective and feasible measures to reduce the risk of mould growth on the products, the project “Efficient production of mould-free pinnekjøtt and cured meat products” was started up in 2015.

The project consisted of six work packages:
WP1: Identification of mycobiota in production facilities
WP2: Effect of production conditions on mould growth
WP3: Use of novel methods for mould detection
WP4: Evaluation of production chains
WP5: Implementation of cost-efficient measures
WP6: Dissemination of results

Two production facilities were selected, their mycobiota was identified throughout three production seasons and the main problem organisms were identified. Selected isolates were examined for toxin production potential and store-bought products were analysed to rule out the presence of undesired toxins in the products.

Experiments on growth media, pinnekjøtt and cured ham and sausages identified humidity in production and storage facilities, salt concentrations in the product, packaging atmosphere and use of antifungals (potassium sorbate) as critical control factors for mould growth on the product while freezing and the use of protective cultures did not have any implications on mould growth.

Since moulds spread easily through the air, it is impossible to keep a production environment mould-free at any time. However, there are great differences between mould species, and many species do not pose a problem for product quality and safety. It is therefore important to have good detection tools that can identify early increases in occurrence of the undesired mould species. FTIR and MALDI-TOF were tested as methods for early detection of problem moulds and results showed that especially FTIR might be suited to screen large amounts of samples for specific mould species. While this method alone is not sufficient to identify all mould species, it might help identifying increases in toxin-producing mould species.

Furthermore, the production chains in the two plants were evaluated and areas with potential for improvement were identified. These included procedures for salting, rinsing and salt removal and storage conditions (room solutions, humidity, adaptations for specific product types). All points were reviewed with quality management and project management and several upgrades have been made in the facilities, especially to reduce humidity, resulting in reduced mould growth in the respective areas.

The final project meeting was held at one of the production facilities in October 2018 with participants from VI, Nofima, Nortura and the involved producers. At this opportunity, employees were invited and participated in an educational lecture and discussion about mould.

Producers reported a number of positive results of the project , including reduced visible mould growth at the facilities (resulting in reduced manpower needed to control mould growth), increased collaboration between facilities, increased awareness among employees and reduced numbers of customer complaints related to mould growth.

Project facts:
Name: «Efficient production of mould-free pinnekjøtt and dry cured meat products»
Duration: September 2015-November 2018
Participants: Nortura (project owner), the Norwegian Veterinary Institute (project leader), Nofima, Animalia, the Technical University of Denmark

The mycobiota of the production environments of traditional Norwegian salted and dried mutton (pinnekjøtt). International Journal of Food Microbiology 2018; 276; 39-45