Andrea Osimani is a PhD Associate Professor in Agricultural Microbiolgy, he is author of 71 international scientific papers indexed in Scopus (874 citations; h-index 17) or ISI Web of Knowledge and has been serving as an editorial board member of reputed Journals. He is currently Professor for the Courses of Hygiene, Microbiological Risk Management and Laboratory of Microbiology at the Department of Agricultural, Food and Environmental Sciences - Polytechnic University of Marche, Italy. His research activity is focused in the study of microbial dynamics in conventional and unconventional foods and environmental matrices.
Fermented marine-based products are currently consumed by several cultural groups worldwide. Brilliant examples of traditional fermented fish products are represented by surstroomming and rakfisk, produced in Sweden and Norway, respectively, and hakarl, produced in Iceland. Hakarl is produced by curing of the Greenland shark (Somniosus microcephalus) flesh that, before fermentation, is toxic for the high content of trimethylamine (TMA) or trimethylamine N-oxide (TMAO). Despite its long history of consumption, there is a lack of knowledge on the microbial consortia involved in the fermentation of this fish. In the present study samples of ready-to-eat hakarl were subjected to viable counting of bacteria and eumycetes on different selective growth media. The DNA extracted directly from the hakarl samples was further subjected to Polymerase Chain Reaction-Denaturing Gradient Gel Electrophoresis (PCR-DGGE) and 16S rRNA gene amplicon based sequencing (Illumina sequencing). Viable counting revealed by the presence of total mesophilic aerobes, lactic acid bacteria, and Pseudomonadaceae. The dominance of closest relatives to Tissierella creatinophila was evidenced by PCR-DGGE. Moreover, the main operational taxonomic units (OTUs) shared among the data set were Tissierella, Pseudomonas, Oceanobacillus, Abyssivirga, and Lactococcus. The detection of Pseudomonas by Illumina sequencing supports the hypothesis of a possible role of this microorganism on the detoxification of shark meat from TMAO or TMA during fermentation. Further studies are needed to establish the role and the viability of the detected microbial species during shark fermentation, as well as their interactions and correlation with physical-chemical and rheological traits of hakarl.
Maha Usama Abdelhaseib received her bachelor of veterinary medicine degree (BVSc) from Egypt, completed her Master dergee in Food Hygiene at 2009 Egypt and her PhD as Visiting scholar in the Food Science departement at Purdue University IN USA in 2014, Right after, she has started her postdoctoral studies at Purdue University in 2016. She is Lecturer at Food Hgiene departement Assiut University, Egypt. She is motivated researcher working in the core and interdisciplinary area of molecular microbiology, pathogen detection, biosensors, food microbiology and safety.
Aim: To investigate the use of a light scattering sensor, BARDOT (BActerial Rapid Detection using Optical scattering Technology) coupled with a multi-pathogen selective medium, SEL (Salmonella, Escherichia, and Listeria) for concurrent detection of the three major foodborne pathogens in a single assay. Methods and Results: BARDOT was used to detect and distinguish the three major pathogens, Salmonella enterica, Shiga-toxin producing Escherichia coli (STEC) and Listeria monocytogenes on colony scatter signature patterns on SEL agar (SELA).Multiple strains of three test pathogens were grown on SELA, and BARDOT was used to generate colony scatter image libraries for inclusive (SEL-Library) and exclusive (non-SEL Library) bacterial group. These pathogens were further differentiated using the SEL scatter image library. The BARDOT sensor successfully detected and differentiated Salmonella, STEC, and Listeria on SELA with high classification accuracy 92-98%, 91-98%, and 83-98% PPV, respectively; whereas the non-target strains showed only 0-13% PPV. BARDOT identified colonies were further confirmed by multiplex PCR targeting inlB gene of L. monocytogenes, stx2 of STEC and sefA of S. Enteritidis. Conclusions: The results show that BARDOT coupled with SELA can efficiently detect and differentiate the presence of three pathogens. Significance and Impact of the Study: This innovative SELA-BARDOT detection platform can reduce turn-around-time and economic burden on food industries by offering a label-free, non-invasive on-plate multi-pathogen screening technology for reducing microbial food safety and public health concerns.