An Vermeulen, Mieke Uyttendaele, Geert Gins, Anja De Loy-Hendrickx, Hubert Paelinck, Jan Van Impe and Frank Devlieghere

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1 An Vermeulen, Mieke Uyttendaele, Geert Gins, Anja De Loy-Hendrickx, Hubert Paelinck, Jan Van Impe and Frank Devlieghere LFMFP Laboratory of Food Microbiology and Food Preservation, Ghent University, Belgium BioTeC Chemical and Biochemical Process Technology and Control, KULeuven, Belgium KaHo Sint-Lieven, Belgium

2 Introduction L. monocytogenes in RTE-foods (EU-legislation N 2073/2005) (i) RTE foods for infants and for special medical purposes absence in 25 g (ii) RTE foods able to support growth, other than those intended for infants and for special medical purposes absence in 25 g (before the food has left the immediate control of the food producer) 100 CFU/g (products placed on the market during their shelf-life) (iii) RTE foods unable to support growth, other than those intended for infants and for special medical purposes 100 CFU/g (products placed on the market during their shelf-life)

3 Introduction Industrial project in cooperation with 30 manufacturers of processed meat and with interaction with the Belgian food safety authority Need for: Profound validation of existing models Transfer of knowledge to the industry Aim: Reduction in the amount of challenge tests, needed to prove the compliance with EU 2073/2005 Stimulate product innovation in the companies

4 Scheme of the research Overview of existing models Intrinsic and extrinsic properties of meat products Challenge tests to assess growth potential Validation in industrial products Data collection on model products Validation historical data Challenge tests to assess growth rate Challenge tests to assess growth potential Listeria Meat Model

5 Scheme of the research Overview of existing models Intrinsic and extrinsic properties of meat products Data collection on model products Validation in industrial products Validation historical data Listeria Meat Model

6 Intrinsic and extrinsic factors Processed meat divided in 5 categories 1. Cooked meat products with meat structure (e.g. cooked ham) 2. Cooked meat products without meat structure (e.g. frankfurter, pâté) 3. Salted, cured meat products (e.g. bacon) 4. Fermented meat products (e.g. salami) 5. Aspic products

7 Intrinsic and extrinsic factors Data collected from companies: Extrinsic properties: Shelf-life, storage temperature, Intrinsic properties: ph, lactic acid, acetic acid, nitrite Packaging: MAP (gas composition and gas/product ratio), vacuum Data formed the basis for the recipe for model products (decided by the participating companies)

8 Scheme of the research Overview of existing models Intrinsic and extrinsic properties of meat products Data collection on model products Validation in industrial products Validation historical data Listeria Meat Model

9 Log CFU/g Data collection challenge testing Extensive challenge tests to assess growth rate Two monocultures of L. monocytogenes Constant temperature (T ref = 7 C ) 15 data points (for each growth curve) Fysico chemical parameters at day 0 and end shelf-life Analysis of background flora 9 8 µ max µ maxref T T ref T 2 min 2 min T µ max,ref 2 logcfu/g µ max, i d i Time (d)

10 Log CFU/g Results MAP cooked ham: growth rate Batch 1 Batch L. mono 1 L. mono Time (days)

11 Log CFU/g Results MAP cooked ham: growth rate Linear regression Time (days)

12 Log CFU/g Results MAP cooked ham: growth rate COMBASE Linear regression Time (days)

13 Log CFU/g Results cooked ham: growth rate COMBASE Linear regression SSSP with background flora Time (days)

14 Log CFU/g Results cooked ham: growth rate COMBASE Linear regression SSSP with nitrite SSSP with background flora Time (days)

15 Results MAP cooked meat with adaptation factor Category 1: cooked meat products with meat structure Category 2: cooked meat products without meat structure

16 Results other categories Category 3: salted, cured meat products: no growth of L. monocytogenes Category 4: fermented meat products: no growth of L. monocytogenes Category 5: aspic meat products: extra adaptation factor

17 Data collection challenge tests Challenge tests to assess growth potential Cocktail of strains Time-Temperature profile Analyses in threefold at day 0 and end of shelf-life Fysico chemical parameters at day 0 and end of shelf-life

18 Data collection challenge tests N Inoculum Preculturing conditions T-profile 1 Cocktail 4 7 C 7d@8 C+15d@12 C 2 Cocktail 4 7 C 14d@4 C+8d@8 C 3 Cocktail 4 7 C 24d@4 C+12d@8 C EU (1) LFMFP (2-4) Intern 8 4 Retail 12 4 Consumer 12 8

19 Results cooked ham: growth potential N Day 0 THT δ < Models LMM SSSP 1 SSSP 2 SSSP 1: with nitrite without background flora SSSP 2: without nitrite with background flora

20 Results cooked ham: growth potential N Dag 0 THT δ < Models LMM SSSP 1 SSSP SSSP 1: with nitrite without background flora SSSP 2: without nitrite with background flora

21 Conclusions Challenge tests are expensive for companies, particularly if 3 x 3 tests are necessary Predictive models are a very good alternative Should be profoundly validated in products - cooked ham no interaction with background flora - aspic products interaction with background flora

22 Scheme of the research Overview of existing models Intrinsic and extrinsic properties of meat products Data collection on model products Validation in industrial products Validation historical data Listeria Meat Model

23 Listeria Meat Model

24 Listeria Meat Model

25 Listeria Meat Model

26 Acknowledgement You, for your attention