View metadata,Downloaded citation and from similar orbit.dtu.dk papers on:at core.ac.uk Dec 18, 2017 brought to you by CORE provided by Online Research Database In Technology Rapid Quantification of Viable Campylobacter from Chicken Carcasses, Using Real- time PCR and PropidiumMonoazide Treatment, as a Tool for Quantitative Risk Assessment Josefsen, Mathilde Hasseldam; Löfström, Charlotta; Hansen, Tina Beck; Christensen, Laurids Siig; Olsen, John E.; Hoorfar, Jeffrey Published in: IAFP Annual Meeting 2011 Publication date: 2011 Document Version Publisher's PDF, also known as Version of record Link back to DTU Orbit Citation (APA): Josefsen, M. H., Löfström, C., Hansen, T. B., Christensen, L. S., Olsen, J. E., & Hoorfar, J. (2011). Rapid Quantification of Viable Campylobacter from Chicken Carcasses, Using Real-time PCR and PropidiumMonoazide Treatment, as a Tool for Quantitative Risk Assessment. 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P1-01 Prevalence of Spore-forming Bacteria in Food Using a Multiparametric PCR-based Tool FLORENCE POSTOLLEC, Muriel Bernard, Marie Laure Divanac’h and Danièle Sohier ADRIA Developpement, Quimper, France Introduction: Sporeforming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuffs. Purpose: The state-of-the-art of sporeformers’ prevalence in ingredients and food was investigated using a multiparametric PCR-based tool that enables simultaneous detection and identification of various genera and species mostly encountered in food, i.e.,Alicyclobacillus , Anoxybacillus flavithermus, Bacillus, Bacillus cereus group, Bacillus licheniformis, Bacillus pumilus, Bacillus sporothermodurans, Bacillus subtilis, Brevibacillus laterosporus, Clostridium, Geobacillus stearothermophilus, Moorella and Paenibacillus species. Methods: A total of 90 food products, with or without visible trace of spoilage were analyzed, i.e., 30 egg-based products, 30 milk and dairy products and 30 canned food and ingredients. Detection and identification of targeted species were performed using GeneDisc® Plate. In addition, spore enumeration and isolate 16S rDNA sequencing was used to validate PCR-based tool identification and identify other possible contaminants. Results: Good correlations between the microbiology and molecular-based approach underline the great performance of this multi-detection tool. Most samples contained one or several of the targeted genera and species. For all three tested food categories, 30 to 40% of products were contaminated with both Bacillus and Clostridium. The percentage of contaminations associated with Clostridium or Bacillus represented 100% in raw materials, 72% in dehydrated ingredients and 80% in processed foods. In the last two product types, additional thermophilic contaminants were identified Anoxybacillus( flavithermus, Geobacillus spp., Thermoanaerobacterium spp. and Moorella spp.). Significance: The results suggest that selection, and therefore the observed (re)-emergence of unexpected sporeformer contaminants in food might be favored by the use of given food ingredients and food processing technologies. P1-02 Prevalence and Heat Resistance of Thermophilic Spore-forming Bacteria Contaminating Milk Powder FLORENCE POSTOLLEC, Muriel Bernard, Anne Lochardet and Danièle Sohier ADRIA Developpement, Quimper, France Introduction: Spore-forming bacteria are ubiquitous in the environment and exhibit a wide range of diversity leading to their natural prevalence in foodstuffs. More particularly, thermophilic spore-formers such as Anoxybacillus flavithermus is not detected in raw milk but is frequently encountered in spray-dried milk powder. Purpose: The aim of this study was to investigate the prevalence of spore-formers in milk and milk powder samples and determine wet heat resistances of spores naturally found to contaminate milk powders. Methods: Several raw, pasteurized and processed milk samples were analyzed together with milk powder samples. Detection and identification of spore-forming bacteria was performed using GeneDisc® Plate multi-parametric tool. In addition, spore enumeration and isolate 16S rDNA sequencing was used to validate PCR-based tool identification and identify other possible contaminants. Mixed, naturally-encountered spores were collected from milk powder by filtration and wet heat resistances were evaluated on mixed spore suspensions. Milk powder major contaminants, i.e., Geobacillus and Anoxybacillus, were used to produce spores, for which heat resistance was determined. Results: Native spores concentrated from raw milk samples show low spore counts with high spore-former diversity while processed and milk powders show lower diversity. Bacillus coagulans, Bacillus licheniformis, and Ureibacillus thermosphaericus were recovered in raw milk and processed milk. Species found in milk powders were mainly composed of thermophilic species such as Geobacillus stearothermophilus, Anoxybacillus flavithermus and Ureibacillus spp. Heat resistance of dominant spore-former contaminants in milk powder enable spore survival to industrial processes. Significance: These results suggest that selection, and therefore the observed (re)-emergence of unexpected spore-former contaminants in food might be favored by the use of given food processing technologies. P1-03 Modeling the Impact of Temperature and Water Activity on the Growth of Aspergillus flavus, Cladosporium cladosporoïdes, Eurotium herbariorum, Penicillium chrysogenum and Wallemia sebi Thibaud De Broucker, Mohammed El Jabri, FLORENCE POSTOLLEC, Danièle Sohier and Dominique Thuault ADRIA Developpement, Quimper, France Introduction: Development of molds such as Aspergillus flavus, Cladosporium cladosporoïdes, Eurotium herbariorum, Penicillium chrysogenum and Wallemia sebi is responsible for various food spoilage. Poster Purpose: The aim of this work is to develop a predictive model to simulate mold growth in bakery foodstuffs taking into account the impact of temperature and water activity (aw) on fungal development. Methods: Potato Dextrose Agar medium with a wide range of aw (from 0.8 to 0.99) was performed after glycerol adjustment. Temperature was studied in the range of 10 to 40°C. Two parameters of fungal development were taken into account, i.e., growth rate, expressed as the increase of colony diameter per day, and the lag time or apparition time of molds. The Rosso model (1993) was used to describe the influence of temperature and aw on growth rate. Cardinal values were determined for water activity (awmin, awopt and awmax) and temperature (Tmin, Topt, Tmax) for each studied mold. Results: Molds tested presented different optimal growth temperatures, i.e., Wallemia sebi had the lowest Topt (21°C) and Aspergillus flavus the highest (31°C). Great differences were also observed for the minimum aw values for growth (awmin): Eurotium herbariorum had the lowest awmin value (0.70) and Wallemia sebi had the highest awmin value (0.74). Great correlations were observed between this study and published cardinal values for temperature. Except for Wallemia and Eurotium, for which it was shown lower awmin value than published data. Using the developed model, optimal growth rates (µopt) of the five species of mold were also evaluated on bakery products during storage at 25°C (with various formulations and various aw). No impact of the formulation on the growth rate was observed. Significance: This study shows that predictive models developed for the simulation of bacterial growth may be used to describe the development of molds on bakery product matrices. 1 P1-04 Tolerance of Bacillus cereus against Low-dose γ-Irradiation and Cold Temperature Storage ADELARD B. MTENGA, Neema Kassim, Wongyeong Lee, Jeon-Eon Song and Duck-Hwa Chung Gyeongsang National University, Jinju, Gyeongsangnam-do, Republic of Korea Introduction: Gamma irradiation has been highly recommended as a sanitary treatment to ensure the safety of food and food products from microbiological contamination. Bacillus cereus has been implicated in foodborne outbreaks. The majority of bacteria barely withstand γ-irradiation up to 5 kGy and cold temperature treatment. Purpose: The objective of this study is to investigate the level of tolerance of Bacillus cereus strains KCCM 40138 to the combined treatment of low-dose γ-irradiation and storage at 0°C for 24 h after irradiation. Methods: B. cereus at a concentration of 1.5 x 107 CFU/ml were exposed to the γ-irradiation dose of 0, 1, 1.5, 3 and 5 kGy and immediately stored at 0°C for 24 h. The optical density and the antimicrobial sensitivity profile were measured to compare the changes in between before and after the radiation treatment. PCR analysis that targets B. cereus gyrB gene