We have compared the efficacy of continuous ultraviolet (UV‐C) (254 nm) and pulsed UV light in reducing the viability of Salmonella Enteritidis, Listeria monocytogenes, Staphylococcus aureus, enterohemorrhagic Escherichia coli, Pseudomonas spp., Brochothrix thermospacta, Carnobacterium divergens, and extended‐spectrum β‐lactamase producing E. coli inoculated on chicken fillet surface. Fluences from 0.05 to 3.0 J/cm2 (10 mW/cm2, from 5 to 300 s) used for UV‐C light resulted in average reductions from 1.1 to 2.8 log cfu/cm2. For pulsed UV light, fluences from 1.25 to 18.0 J/cm2 gave average reductions from 0.9 to 3.0 log cfu/cm2. A small change in the odor characterized as sunburnt and increased concentration of volatile compounds associated with burnt odor posed restrictions on the upper limit of UV treatment, however no sensory changes were observed after cooking the meat. Treatments under modified atmosphere conditions using a UV permeable top film gave similar or slightly lower bacterial reductions.Practical applicationsUltraviolet (UV) light may be used for decontaminating the surface of food products and reduce viability of pathogenic and spoilage bacteria. Exposure of raw chicken fillet surface to various doses of continuous UV‐C or pulsed UV light proposed in the present work represent alternatives for microbiological improvement of this product. Chicken fillets can be treated in intact packages covered with UV permeable top film, thus avoiding recontamination of the meat. UV‐C light treatment is a low cost strategy with low maintenance, whereas pulsed UV light involves more elaborate equipment, but treatment times are short and less space is required. Both methods can be helpful for producers to manage the safety and quality of chicken fillets.

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Sour beer is beer with an intentionally sour taste. In traditionally produced sour beer, the acidic character results from spontaneous, mixed fermentation where different bacteria and yeast species participate. These complex fermentations take years to complete and can be difficult to control. Owing to the increasing interest in sour beer and challenges related to commercial sour beer brewing, alternative production methods are being explored. In the current paper, pre‐fermentation with lactic acid bacteria (LAB) was investigated as a timesaving and controllable strategy for the production of sour beer. Four beers were produced with either biological or chemical acidification of wort, and a reference beer was produced with no acidification. Volatile compounds and organic acids were analysed by headspace gas chromatography and high‐performance liquid chromatography to explore any contribution from LAB to the composition of beer. Finally, descriptive sensory analysis was performed to evaluate the sensory contribution from LAB. A significant effect was observed from LAB pre‐fermentation, with respect to both volatile compounds (e.g. reduced production of 2‐methyl‐1‐butanol) and organic acids (e.g. production of acetic acid). Biological acidification by LAB pre‐fermentation had a significant impact on the sensory character of beer. This sensory impact did, however, not surpass that obtained by chemical acidification, as few significant differences were found between biologically and chemically acidified beers. © 2019 The Institute of Brewing & Distilling

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