Software for risk assessment of Listeria in ready-to-eat meat products.

Companies producing ready-to-eat meat products, which are products that are consumed without cooking by the consumers, are responsible for determining the shelf lives for their products. The shelf life is estimated based on the possible growth rate of the Listeria and is defined as the time a product can be stored before the number of Listeria has multiplied to the legal limit value. This can be done either by testing the Listeria growth in experiments, where Listeria is added to the product and the growth rate is measured (expensive to perform), or companies can use software for estimation. There are some software on the market, but they are rarely used by FBOs. This is due to poor user friendliness and they require that product analyzes have been carried out in advance. Several software are based on experiments with Listeria in broths and not in products. In broth, Listeria grow faster, and the calculated shelf lives are shorter. A more correct and longer shelf life can give less food waste. ListWare aims to be more user-friendly, based on product groups, processes, and packaging methods, and key criteria are identified and included in the calculation of shelf life. This will contribute to more accurate risk assessments. Many analyzes have been performed for different meat products, for identifying the level and range of pH, water activity, inhibitory additives such as acetate, lactate and nitrate and amount of background flora with competing lactic acid bacteria. In 2018, a growth study with cold cuts (roast beef) was performed at the Veterinary Institute. The main experiment had experimental design with high, low and medium levels of five factors in 51 factor combinations; storage temperature, core temperature at boiling, packing method and added acetate and lactate. It involved a total of 622 samples. The results were read every second-third day for 3-4 weeks, depending on how quickly the bacteria grew in the factor combination. The design provided a lot of information for the modeling. Two models were developed; a polynomial model based on linear regression analysis, and a more advanced Gamma model. There are different input factors for the two models. Statisticians from Animalia, Veterinary College, with contributions from foreign researchers have developed the models. The models were then tested in validation studies, in laboratories at the universities of Bologna in Italy, Leon in Spain and NMBU in Oslo. In this way, different products, laboratories, Listeria strains, etc. were tested. This autumn, new growth studies are performed at the Veterinary Institute with different kinds of cold cuts. New models are developed. A first version of software designed for food companies has been programmed. Product groups with their characteristics are included in tables. Users must enter the packaging type and storage temperature. The two models are used to calculate shelf life. The result is presented as the number of days and a graph with a growth curve and a graph with a curve for the uncertainty. This is useful input for risk assessments. The user can print a report that can be used as documentation to the Norwegian Food Safety Authority. The project group consists of 5 large food producing companies in Norway and these are involved in the development and testing of software. It is a clear advantage that future users will also help develop the program. When planning the software, a working group tested existing software on the market, to provide input and advice for our programming. Data for results and product information from previous studies and from the literature are collected in a database. This data is used to validate the models and to compare product characteristics. There is high activity in the project with regular project group meetings with participants from Norwegian food companies, the Veterinary Institute, and Animalia. Several posters have been created about ListWare and presented; at the Predictive Modeling Congress in Braganza September 2019 and Cordoba in 2017, FoodMicro Congress in Berlin in September 2018. In addition to the project team, international Listeria researchers from Spain, Italy, France, Switzerland, Germany and Norway also participate in planning, validation studies, statistics and writing articles. They have attended two workshops in Oslo in addition to regular skype meetings.

Målgruppen for software er bedrifter som produserer spiseklare matvarer. Disse matbedriftene har ansvaret for risikovurdering av Listeria-vekst i sine produkter og sette holdbarheter som gir trygg mat. Ved å ta i bruk nytt software vil matbedriftene kunne redusere kostnader til eventuelle vekststudier av Listeria for sine produkter, få sikrere input i sine risikovurderinger, og de kan vurdere bruk av aktuelle tilsetninger som acetat og lactat, som kan hemme Listeriavekst og forlenge holdbarhetene. Beregning av en mer korrekt (lengre) holdbarhet, vil man redusere matsvinn hos forbruker og butikk. Det vil også bidra til å redusere antall tilbaketrekninger av produkter. Softwaregrensesnittet vil være et nyttig verktøy for produktutvikling, beslutningsstøtte, vurderinger av konsekvenser av utilsiktet variasjon og benchmarking av produkter, samt redusere sykdomstilfeller på grunn av Listeria. ListWare vil dermed være en bærekraftig økonomisk og helsemessig fordel for samfunnet.

The project will develop a web based software for assessing growth of Listeria in meat products and mixed products where meat is a main ingredient, which will give more accurate and specific results for shelf lives than the tools food business operators have available today. Listeria is a challenge in ready-to-eat foods, and the risk management involve large expenses and time spent for the FBOs. The software will mean saving of time and costs for the FBOs. EU regulation establishes that food safety is the responsibility of FBOs, and they must assess the risk of listeriosis for their products, to make sure that the maximum limit set in the legislation is not exceeded at any time during the shelf life. Long shelf lives are positive for both environmental and economic reasons. The options for FBOs are either performing expensive laboratory challenge tests or apply predictive modelling. However, available softwares for predicting Listeria growth do not cover the huge variety of products, ingredients and additives, which might result in incorrect estimation of growth. ListWare project will establish a database with quality assured data collected from previously challenge tests, identify gaps in existing data regarding factors and hurdles affecting Listeria growth, set up criteria for acceptable variation for categorization of products, perform new challenge tests based on experimental design, and develop better predictive models and algorithms, verified by microbial analyses. Leading European experts will participate in the project. When the database and interface is ready, licenses for access will be sold in both Norway and international. A business model will be made, which also include consultancy from ListWare team for the users.