Effect of chitosan treatments on quality parameters of fresh refrigerated swordfish (Xiphias gladius) steaks stored in air and under vacuum conditions. 
The present study examined the effect of chitosan (1.0% w/v) in combination with packaging on the shelf-life of fresh swordfish steaks.  Treatments included the following: A (untreated, control samples stored in air), A-CH (treated with chitosan 1.0% w/v, stored in air), VP (untreated, stored under vacuum packaging) and VP-CH (treated with chitosan, stored under vacuum packaging).  VP-CH significantly affected Total Viable Counts (TVC), Pseudomonas spp.,  H(2)S-producing bacteria (including Shewanella putrefaciens), lactic acid bacteria and Enterobacteriaceae.  Production of TMA-N and TVB-N for A-CH, VP and VP-CH swordfish samples was significantly lower than for control (A) samples at day 8 of storage.  Histamine formation for all treatments was low.  A-CH and VP-CH resulted in significantly lower levels of putrescine, cadaverine and tyramine (day 8) as compared to A and VP swordfish samples.  Results of this study indicate that the shelf-life of swordfish steaks can be extended using, either aerobic or vacuum packaging and in combination with chitosan, by approximately 4 (A-CH), 8 (VP) and 12 (VP-CH) days.  Swordfish steaks treated with chitosan and stored under VP were sensorially acceptable up to 17days.  The presence of chitosan (A-CH and VP-CH) did not negatively influence the taste of cooked swordfish.