Statistical Methodologies in Confectionery W. Peñaloza and A. Bousbaine

1. Statistical Methodologies in Confectionery W. Peñaloza and A. Bousbaine Nestlé Research Center, P.O. Box 44, 1000 Lausanne 26, Switzerland

2. Background & Objectives Business trend for low fat and reduced calorie to bring guilt free indulgence to consumers Project objectives • Evaluate the microbiological safety and stability of confectionery products • Provide guidance for microbiological challenge testing for the development of similar products

3. Aw 0.8 Aw 0.3 Background & Objectives What do we know • Praline concept & technology developed at NRC (P. Rousset) with industrial potential • Industrial feasibility (Darryl Barwick)

4. Background & Objectives Production End of shelf life • Thorough understanding of product stability against fungal growth (mycotoxins/spoilage) • Challenge testing • (at conditions as close as possible to industrial production) X Shelf life of product & conditions

5. Background & Objectives What needs to be defined for the challenge testing ( likely industrial production) • Recipe (“canada”) – polishing & approval • Product format/presentation praline, moulded or enrobed • Storage e.g. refrigerated, ambient, warm? • Major impact for planning: • Water migration kinetics • Challenge testing (Experimental design)

6. Generic Design Run No Sorbate (%) aW 1 0 0.76 2 0 0.84 3 0.2 0.76 4 0.2 0.84 5 0.1 0.8 Experimental Design • Other Parameters • Format: Bâton and Perforated • Cocktail: None, Safety and Spoilage • Storage Temperature: Refrigerated (10 °C), Ambient (22°C) • and Warm (32 °C)

7. Cocktails • None: no inoculation, but natural contamination • (air, raw materials, clean equipment surfaces, …) • Safety: micotoxigenic moulds (aflatoxines, ochratoxins, …) • Spoilage: moulds found in production line, storage tests, • contaminated raw materials, inadequate hygene • in the production line, …

8. Measurements • Response • Visual Mould Growth • Codification • 0: No growth seen even under the stereomicroscope • 1: Incipient Mycelium growth normally detected after careful inspection and • frequently under the stereomicroscope, detected by specialist • 2: Mycelium growth clearly noticeable as white hairy areas by any • consumer (not specialist) • 3: Abundant mycelium growth and sporulation with or without change of • colour

9. Format: Bâton, Cocktail: NoneResults After 24 Weeks of Storage

10. Format: Bâton, Cocktail: SafetyResults After 24 Weeks of Storage

11. Format: Bâton, Cocktail: SpoilageResults After 24 Weeks of Storage

12. Format: Perforated, Cocktail: NoneResults After 24 Weeks of Storage

13. Format: Perforated, Cocktail: Safety Results After 24 Weeks of Storage

14. Format: Perforated, Cocktail: SpoilageResults After 24 Weeks of Storage

15. Format: Bâton & Perforated, Cocktail: SpoilageResults After 24 Weeks of Storage

16. I Index Response Let be the categories defined to characterize the degree of visual moulds, where Let k be the number of replicates for each combination Formula-Format-Cocktail-Storage Temperature. For each combination Formula-Format-Cocktail-Storage, let be the number of samples with a degree of visual moulds It follows that

17. I Index An index I can be defined as follows: Properties of the I index Situation 1 then Situation 2 then

18. I Index • Statement • Proof • By definition, it is clear that • We have to show that • We have • Since • It follows that because

19. Weights Visible mould growth (spoilage) stationary phase Completely mouldy 3 high aw noticed by consumer 2 exponential phase noticed by expert 1 low aw lag phase Storage time

20. Weights Growth 10 Abundant 7.5 Consumer 2.5 Specialist Initial Inoculation 0 Time Germination Growing

21. Modelling • Response • I index • Modelling • A model relating the I index to the 2 parameters Sorbate and aW is • established for each combination Format-Cocktail-Storage Temperature. • The contour plots of the established models are given in the next slides.

22. Results After 24 Weeks of Storage

23. Results After 24 Weeks of Storage

24. Results After 24 Weeks of Storage

25. Results After 24 Weeks of Storage

26. Results After 24 Weeks of Storage

27. Results After 24 Weeks of Storage

28. Results After 24 Weeks of Storage

29. Results After 24 Weeks of Storage

30. Results After 24 Weeks of Storage

31. Conclusions • After 24 weeks of storage, visual mould growth appears mainly when the • cocktail is spoilage and when the storage temperature is ambient. • Visual mould growth is seen on the combinations No 2 and 4. • Visual mould growth is more pronounced when the samples are perforated. • Combination No 2 does not contain Sorbate and has an aW of 0.84. • Combination No 4 contains 0.2% Sorbate and has an aW of 0.84. • The results show that: • aW plays an essential role • Sorbate plays also a role, but less pronounced • Storage temperature plays also a role. Ambient temperature increases the • degree of visual mould growth. • Format plays as well a role. Perforation increases the degree of visual • mould growth.

32. Conclusions • The established I index characterizes very well the degree of visual moulds, • and allows a very easy and understandable way of communicating the • results. • From the modelling using the I index, it appears that: • Cocktails: None and Safety • aW is the key parameter, and this parameter should be as low as possible. • Sorbate plays a slight role. It helps a little bit. • 2. Cocktail: Spoilage • aW is the key parameter, and it should be kept at its lowest value. • Sorbate plays a negligible role. It brings more or less nothing! • The effect of Format is also highlighted in the modelling results.

33. Acknowlegements • The authors wish to thank all the people involved in the whole project, in • particular: • V. Meunier • P. Rousset • A. Rytz

34. Thank you for your attention !