The objective of this study was to determine important chemical characteristics of a full-strength liquid smoke, Code 10-Poly, and three refined liquid smoke products (AM-3, AM-10 and 1291) commercially available (Kerry Ingredients and Flavors, Monterey, TN). The pH of the products were significantly different (P < 0.05) and ranged from 2.3 (Code 10-Poly) to 5.7 (1291). The pH was inversely correlated with titratable acidity (R2 = 0.87), which was significantly different (P < 0.05) among products ranging from 10.3% acetic acid (Code 10-Poly) to 0.7% acetic acid (1291). Total phenol content was quantified using the Gibbs reaction; the only liquid smoke containing appreciable level of phenolic compounds was Code 10-Poly at 3.22 mg mL−1. Gas chromatography-mass spectrometry (GC-MS) analysis of liquid smoke dichloromethane extracts revealed that carbonyl-containing compounds were major constituents of all products, in which 1-hydroxy-2-butanone, 2(5H)-furanone, propanal and cyclopentenone predominated. Organic acids were detected by GC-MS in all extracts and correlated positively (R2 = 0.98) with titratable acidity. The GC-MS data showed that phenolic compounds constituted a major portion of Code 10-Poly, and were detected only in trace quantities in 1291. The refined liquid smokes had lighter color, lower acidity, and reduced level of carbonyl-containing compounds and organic acids. Our study revealed major differences in pH, titratable acidity, total phenol content, color and chemical make-up of the full-strength and refined liquid smokes. The three refined liquid smoke products studied have less flavor and color active compounds, when compared with the full-strength product. Furthermore, the three refined products studied have unique chemical characteristics and will impart specific sensorial properties to food systems. Understanding the chemical composition of liquid smokes, be these refined or full-strength products, is an important step to establish their functions and appropriate use in food systems.

Five commercial liquid smokes were tested in vitro and the most inhibitory to Listeria monocytogenes ATCC 19115 and L. innocua ATCC 33090 was Charsol Supreme. Chum salmon samples (100‐g each) were brined, dipped for 15 s at varying concentrations of liquid smoke, inoculated with L. innocua, cold‐processed and analyzed. Liquid smoke concentrations of 60–100% reduced L. innocua by 3‐log10/g in the final product. Dwell times of 15 s to 5 min using 60% liquid smoke gradually decreased Listeria survival with an optimum 5‐min dip. Isoeugenol was antilisterial in vitro but lacked synergism with liquid smoke in cold‐smoked salmon. An immunoassay kit detected low inoculum levels (< 100 CFU/g) of L. innocua in one of three samples that were treated with liquid smoke for two and four minutes. Charsol Supreme was antilisterial but could not be relied on to totally eliminate Listeria in cold‐smoked salmon. Panelists found the 0 to 2‐min dipped sockeye salmon slightly desirable with no significant (p < 0.05) differences. The 5‐min treatment was significantly (p < 0.05) darker, scored lower in desirability and flavor and contained 93 ppm of phenolic compounds.

Aims: To investigate factors in¯uencing bacteriocin production and bacteriocin stability of the bioprotective culture Carnobacterium piscicola strain A9b. Methods and Results: Maximum activity was obtained in MRS7 broth (MRS adjusted to pH 7á2), with or without glucose. No bacteriocin was produced in APT broth when a low inoculum level (0á001%) was used. In contrast, inoculum level did not in¯uence bacteriocin production in BHI and MRS7 without glucose. Bacteriocin production in APT was induced by the presence of an extracellular compound present in the sterile, ®ltered, cell-free supernatant uid of a stationary-phase culture. Increasing concentrations of NaCl (2±7%) reduced bacteriocin production and maximum cell density of C. piscicola A9b when grown in cooked ®sh juice at 4°C. Conclusions: Media composition, inoculum level and sodium chloride concentration affected production. Signi®cance and Impact of the Study: The in¯uence of NaCl on bacteriocin production may negate the inhibitory effect of C. piscicola A9b against Listeria monocytogenes in salty foods.

The objective of this project was to provide relevant information to Alaska shellfish growers regarding the intrinsic quality of their farmed oysters. A 1‐y study was conducted to determine the condition indices, proximate composition, fatty acid content, and microbial load of commercially harvested oysters from 3 different mariculture regions in the state of Alaska. Oysters from farms located in the regions of Prince William Sound, Kachemak Bay, and Southeast Alaska were sampled according to the farmers' harvest schedules. Our results suggest that Alaskan maricultured oysters have slight seasonal and regional differences. The condition indices of Alaska oysters were high, indicating an excellent quality product. The chemical composition and fatty acid profile of C. gigas from Alaska waters are in agreement with the values reported for mariculture oysters of same species from different parts of the world. The microbial content of Alaskan oysters varied widely between shipments from each specific geographic region and could not be correlated to either harvest time or transit time.

Pink salmon were stored up to ten days in ice, chilled seawater (CSW), transferred from ice to CSW and from CSW to ice, and evaluated by chemical, physical, microbiological, and sensory methods. The sensory quality of CSW-held fish declined at a faster rate than for iced fish. CSW-held fish had higher weight gain, higher salt and hypoxanthine levels and had softer texture than iced fish. Microbial counts were highest for iced fish and a two-log increase occurred during storage. Moraxelia species were predominanr in the microbial flora of iced fish whereas Pseudomonas species were predominant in the microbial flora of CSW-held fish. Ice was superior to CSW for maintaining salmon quality.