Viologen-inspired aromatic molecules, polymers, and functional materials and their versatile applications will be introduced in this review.

The objective of this study was to establish a multiplex real-time PCR for the simultaneous quantitation of Escherichia coli O157:H7, Salmonella, and Shigella. Genomic DNA for the real-time PCR was extracted by the boiling method. Three sets of primers and corresponding TaqMan probes were designed to target these three pathogenic bacteria. Multiplex real-time PCR was performed with TaqMan Universal PCR Master Mix in an ABI Prism 7700 Sequence Detection System. Final standard curves were calculated for each pathogen by plotting the threshold cycle value against the bacterial number (log CFU per milliliter) via linear regression. With optimized conditions, the quantitative detection range of the real-time multiplex PCR for pure cultures was 10(2) to 10(9) CFU/ml for E. coli O157:H7, 10(3) to 10(9) CFU/ml for Salmonella, and 10(1) to 10(8) CFU/ml for Shigella. When the established multiplex real-time PCR system was applied to artificially contaminated ground beef, the detection limit was 10(5) CFU/g for E. coli O157:H7, 10(3) CFU/g for Salmonella, and 10(4) CFU/g for Shigella. Immunomagnetic separation (IMS) was further used to separate E. coli O157:H7 and Salmonella from the beef samples. With the additional use of IMS, the detection limit was 10(3) CFU/g for both pathogens. Results from this study showed that TaqMan real-time PCR, combined with IMS, is potentially an effective method for the rapid and reliable quantitation of E. coli 0157:H7, Salmonella, and Shigella in food.

Microorganisms play a crucial and unique role in fish and fish product safety. The presence of human pathogens and the formation of histamine caused by spoilage bacteria make the control of both pathogenic and spoilage microorganisms critical for fish product safety. To provide a comprehensive and updated overview of the involvement of microorganisms in fish and fish product safety, this paper reviewed outbreak and recall surveillance data obtained from government agencies from 1998 to 2018 and identified major safety concerns associated with both domestic and imported fish products. The review also summarized all available literature about the prevalence of major and emerging microbial safety concerns, including Salmonella spp., Listeria monocytogenes, and Aeromonas hydrophila, in different fish and fish products and the survival of these pathogens under different storage conditions. The prevalence of antibiotic‐resistant bacteria (ARB) and antibiotic‐resistant genes (ARGs), two emerging food safety concerns, is also reviewed. Pathogenic and spoilage microorganisms as well as ARB and ARGs can be introduced into fish and fish products in both preharvest and postharvest stages. Many novel intervention strategies have been proposed and tested for the control of different microorganisms on fish and fish products. One key question that needs to be considered when developing and implementing novel control measures is how to ensure that the measures are cost and environment friendly as well as sustainable. Over the years, regulations have been established to provide guidance documents for good farming and processing practices. To be more prepared for the globalization of the food chain, harmonization of regulations is still needed.

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The survival of Salmonella, Escherichia coli O157:H7, and Listeria monocytogenes was determined on almonds and pistachios held at typical storage temperatures. Almond kernels and inshell pistachios were inoculated with four- to six-strain cocktails of nalidixic acid-resistant Salmonella, E. coli O157:H7, or L. monocytogenes at 6 log CFU/g and then dried for 72 h. After drying, inoculated nuts were stored at -19, 4, or 24°C for up to 12 months. During the initial drying period after inoculation, levels of all pathogens declined by 1 to -log CFU/g on both almonds and pistachios. During storage, moisture content (4.8%) and water activity (0.4) of the almonds and pistachios were consistent at -19°C; increased slowly to 6% and 0.6, respectively, at 4°C; and fluctuated from 4 to 5% and 0.3 to 0.5 at 24°C, respectively. Every 1 or 2 months, levels of each pathogen were enumerated by plating; samples were enriched when levels fell below the limit of detection. No reduction in population level was observed at -19 or 4°C for either pathogen, with the exception of E. coli O157:H7-inoculated almonds stored at 4°C (decline of 0.09 log CFU/g/month). At 24°C, initial rates of decline were 0.20, 0.60, and 0.71 log CFU/g/month on almonds and 0.15, 0.35, and 0.86 log CFU/g/month on pistachios for Salmonella, E. coli O157:H7, and L. monocytogenes, respectively, but distinct tailing of the survival curves was noted for both E. coli O157:H7 and L. monocytogenes.