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The objectives of this study were to determine the microbial ecology of “blown-pack” fresh beef obtained from a federally inspected facility and to use biopreservation to prevent spoilage of vacuum packaged chilled beef. Organic acids and alcohols in the purge obtained from the “blown” beef packages were detected using HPLC. PCR analysis indicated that Clostridium spp. were present in the purge of the commercial sample. Biochemical tests, RFLP and 16S rDNA sequencing were used to identify organisms isolated from the meat. Out of 66 isolated strains, 26 isolates were strict anaerobes and RFLP indicated that all were clonal isolates. Based on sequence analysis, the isolate was identified as Clostridium putrefaciens. The isolate caused “blown-pack” spoilage and produced butyric and propionic acids when inoculated onto fresh meat and Carnobacterium maltaromaticum UAL307 prevented the production gas and obvious signs of spoilage. / Food Science and Technology

This diploma thesis is focused on the problematic of the smart packaging and deals with the preparation of disposable ammonia sensors/indicators and the subsequent color measurement of prepared sensors/indicators using the CIE L* a* b* color space. The theoretical part of the diploma thesis focuses on active and intelligent packaging, using ammonia sensors/indicators. The emphasis is placed on the main components of the sensor/indicator, i.e., chitosan as a polymer and curcumin as a dye. The theoretical part also includes the problematic of meat degradation, which plays a very important role in this thesis. The experimental part was divided into two parts. The first part was to prepare layers that will respond in different colors based on the concentrations of ammonia. Prepared layers were sensitive to ammonia across all concentrations, and based on this result, ascorbic acid was applied to compositions to achieve a calibration retention of the selected amount of ammonia. The second minor part of the experiment was the application of selected layers to packages with real meat.