SUMMARYNorthern blot hybridization experiments with cDNAs to the four RNA species of a Yugoslavian isolate of beet necrotic yellow vein virus (BNYVV) revealed identical virus RNA patterns in root extracts from field-grown sugarbeets and sugarbeet seedlings grown in soil from rhizomania-afftected fields in various regions in Germany and abroad. In contrast, in leaf extracts from mechanically infected Chenopodium quinoa, Tetragonia expansa and sugarbeet and from a naturally infected sugarbeet we observed great variations in the number, size and relative concentration of the small BNYVV RNAs, which suggests that they may undergo deletion mutations when the virus is propagated in leaf tissues.

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Halophilic and halotolerant bacteria are generally assumed to live in natural environments, although they may also be found in foods such as cheese and seafood. These salt-loving bacteria have only been occasionally characterized in cheese, and studies on their ecological and technological functions are still scarce. We therefore selected 13 traditional cheeses in order to systematically characterize these microorganisms in their rinds via cultural, genomic and metagenomic methods. Using different salt-based media, we identified 35 strains with unique 16S rRNA and rpoB gene sequences, whose whole genome was sequenced. The most frequently isolated species are the halotolerant Gram-positive bacteria Brevibacterium aurantiacum (6) and Staphylococcus equorum (3), which are also frequently added as starters. Their genomic analyses confirm the high genetic diversity of B. aurantiacum and reveal the presence of two subspecies in S. equorum, as well as the genetic proximity of several cheese strains to bovine isolates. Additionally, we isolated 15 Gram-negative strains, potentially defining ten new species of halophilic cheese bacteria, in particular for the genera Halomonas and Psychrobacter. The use of these genomes as a reference to complement those existing in the databases allowed us to study the representativeness of 66 species of halophilic and halotolerant bacteria in 74 cheese rind metagenomes. The Gram-negative species are particularly abundant in a wide variety of cheeses with high moisture, such as washed-rind cheeses. Finally, analyses of co-occurrences reveal assemblies, including the frequent coexistence of several species of the same genus, forming moderately complex ecosystems with functional redundancies that probably ensure stable cheese development.

Aims: Quality evaluation of fresh whitemouth croaker (Micropogonias furnieri) by histamine determination using the HPLC-DAD method and quantification of histamine-forming bacteria using NGS and qPCR. Methods and Results: The histamine content of fresh whitemouth croaker was detected by high performance liquid chromatography with diode array detector with a concentration ranging from 258Á52 to 604Á62 mg kg À1 being observed.

Introduction: The number of registered foodborne diseases involving fresh produce is a preoccupation in many countries. For this reason, the aim of this study was to better understand the growth of Staphylococcus aureus and Escherichia coli, two indicators of hygienic and sanitary conditions, on fruits and vegetables that were exposed at different temperatures. Methodology: The main salads served at the buffets of commercial restaurants were artificially contaminated with separate pools of both pathogens and subsequently exposed at 10, 20 and 30 °C and at different time intervals. Then, the growth potential of S. aureus and E. coli on each fruit and vegetable was determined. Results: There was no significant S. aureus and E. coli growth on all evaluated foods exposed at 10 °C until 6 hours. When comparing both microorganisms, E. coli demonstrated higher growth potential than S. aureus on all analysed salads. Peculiarly, E. coli had the highest growth rate for the tomato (α = 6.43 at 30 °C), a fruit with low pH. Conclusion: We suggest that fruits and vegetables should be distributed at temperatures equal to or lower than 10 °C and should not be kept for more than 2 hours at room temperature.

Primarily formed by the microbial decarboxylation of the amino acid histidine, histamine is the leading global cause of food poisoning from fish consumption worldwide. In the present work, the quality of 12 fresh and 12 frozen marketed sardines ( Sardinella brasiliensis ) were evaluated for histamine concentration using High-performance Liquid Chromatography with Diode-Array Detection (HPLC-DAD), while the detection and quantification of histamine-producing bacteria were performed via quantitative Polymerase Chain Reaction (qPCR), and the microbiota composition of sardines was assessed through amplification of the 16S rRNA gene using high-throughput sequencing (HTS). According to the results obtained by HPLC-DAD, histamine concentration ranged from 226.14 to 583.87 mg kg −1 . The histidine decarboxylase ( hdc ) genes from gram-negative bacteria ( Morganella morganii , and Enterobacter aerogenes ) were identified. The most abundant microorganisms present in fresh sardines belong to the genera Macrococcus spp., Acinetobacter spp., and Pseudomonas spp., while the genera Phyllobacterium spp., Pseudomonas spp., and Acinetobacter spp. were most abundant in frozen sardines.

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