In this study, the microbiological and sensory quality of cultivated mushrooms (Pleurotus ostreatus and eryngii and Lentinula edodes) available at the Austrian retail level were determined. Aerobic mesophilic bacteria (AMC), Enterobacteriaceae (EB), Pseudomonadaceae (PS), lactic acid bacteria (LAB), yeast, moulds and presumptive Bacillus cereus were enumerated at the day of purchase and after storage at 4 °C for 7 or 12 days. Additionally, the presence of Salmonella spp. and Listeria monocytogenes was investigated. Isolates of presumptive spoilage bacteria were confirmed by partial 16S rRNA sequencing. At the day of purchase, 71.2% of the samples were of high microbiological quality and grouped into the low contamination category (AMC < 5.0 log cfu/g), while the sensory quality of 67.1% was categorized as “very good or good”. After storage, the number of samples with high microbial quality was 46.6%, and only 37.0% of the samples scored as “very good or good”. The most abundant species across all mushroom samples were the Pseudomonas fluorescens species complex (58.4%) and the potential mushroom pathogen Ewingella americana (28.3%). All mushroom samples tested negative for Salmonella spp., L. monocytogenes and Bacillus cereus. The microbiological and sensory quality of the analysed mushrooms at the day of purchase and after storage was considered to be good overall. Longer transport distances were found to have a significant influence on the microbiological and sensory quality.

Pathogenic microorganisms surviving in dry products have regularly led to recalls and foodborne disease outbreaks. Therefore, the microbiological quality of 61 dried mushrooms samples purchased online and in supermarkets were analyzed. Counts of aerobic mesophiles (AMCs), Enterobacteriaceae (EB), yeasts and molds, presumptive Bacillus cereus (pBC), the presence of Salmonella spp., and L. monocytogenes were investigated. Isolates of pBC were screened for their partial panC gene sequences and their toxin genes’ profiles. The microbiological quality of the dried mushrooms investigated in this study was generally found to be acceptable. Average AMCs, EB, yeasts, and molds were 3.9 log, 1.1 log, 1.6 log, and 1.5 log cfu/g, respectively. All mushroom samples tested negative for Salmonella spp. and L. monocytogenes. Presumptive BC were detected in 59.0% of the samples, but the contamination level was low (1.0 to 3.4 log cfu/g). None of the isolates were positive for the ces gene. Incomplete labeling was found in 45.9% of the samples, mainly in the form of missing heating instructions (31.1%) and/or country of origin (16.3%). Contamination by pathogens can occur in dried mushrooms. Adequate information on home cooking practices is essential to reduce the risk of foodborne illness to the consumer and to provide a safe food product.

Cold-smoked and Graved salmon are perishable foods that are very popular among consumers. In 2017, 15 samples of cold-smoked and 10 of Graved salmon from the Leipzig retail trade were tested for microbiological and sensory quality as well as pH-value on the last day of consumption date. The microbiological investigations included the parameters total viable count, lactic acid bacteria, Enterobacteriaceae, Listeria (L.) monocytogenes and sulfite-reducing Clostridia. In smoked salmon a mean total viable count of log10 4.50 was found and for Graved salmon of log10 5.34 cfu/g. The median value for the number of lactic acid bacteria was log10 4.46 (smoked salmon) and log10 5.21 cfu/g (Graved salmon), for Enterobacteriaceae at log10 3.60 (smoked salmon) and at log10 3.52 cfu/g (Graved salmon). L. monocytogenes was detected in 2 samples of each sort of salmon and sulfite-reducing clostridia in one of the Graved ­salmon samples. Maldi-TOF MS was used for the differentiation of the main germ flora. Lactobacillus curvatus, Carnobacterium maltaromaticum, Brochothrix thermosphacta, Candida zeylanoides and Serratia spp. were most frequently found. Sensory examinations were performed based on the DLG sensory score (DLG, 2016). As a result, 44 % of the samples achieved scores of 4.8 to 4.0 and 3.9 to 3.1 respectively. 84 % of the samples showed deviations in taste, which were significant in 16 % of them. Only one smoked salmon sample was of impeccable quality and scored 5 points. The pH values of the salmon samples varied between 5.70 and 6.11. The results show that cold ­smoked and Graved salmon may be contaminated with various spoilage microorganisms. L. monocytogenes monitoring must be implemented at all stages of production with the aim to reduce its contamination during manufacturing and in the final products.

Introduction: In Austria, veterinary medicinal products (VMPs) containing penicillin G or cefoperazone are frequently used to treat dairy cows, which leads to the production of non-saleable waste milk. This study aimed to determine the loss of detectable antimicrobial activity of penicillin G and cefoperazone using a commercial ß-lactamase preparation, Antipen®. Methods: Ultra-high-temperature (UHT) processed and raw unpasteurized milk were spiked with penicillin G and cefoperazone (both pure pharmaceutical substances and VMPs), and the effects of temperature (37 °C, 25 °C, and 10 °C), storage time, and pH on Antipen® treatment on antibiotic activity were investigated. The aerobic mesophilic count (AMC) and Enterobacteriaceae before and after enzyme treatment in raw milk were also examined to assess the microbiological quality of milk that is potentially fed to calves. Results: The VMPs containing penicillin G (Vanapen®) or cefoperazone (Peracef®) in 50 mL of UHT or raw milk showed a higher stability after Antipen® treatment compared to pure antibiotic substances. Concentrations of 300 μg/mL of Vanapen® tested negative by Delvotest® T under all experimental conditions (12- and 6-h treatment, at natural pH and pH 5.5, at 37–10 °C). Treatments of milk with natural pH spiked with 10 μg/mL of Peracef® tested negative for the antibiotic after 12 and 6 h at 37 °C, while after acidification of the milk to pH 5.5, 10 μg/mL Peracef® was undetectable at all temperatures and time periods. In milk with natural pH treated with Antipen® for 12 h at 10–37 °C, the values of AMC always exceeded 5.0-log cfu/mL, indicating that the milk is not suitable for use as calf feed without prior acidification or subsequent pasteurization. Reducing the exposure time to 6 h or acidifying the milk to a pH of 5.5 during 12-h treatment significantly reduced bacterial growth. Discussion: This study demonstrated that Antipen® can effectively degrade penicillin, although its efficacy is lower and slower on cephalosporins. Since the study was conducted in a laboratory setting, extrapolation of the effective treatment durations to on-farm application requires validation in practical, real-world conditions.