Inactivation of Listeria monocytogenes in raw and hot smoked trout fillets by high hydrostatic pressure processing combined with liquid smoke and freezing

High hydrostatic pressure (HHP; 200 MPa for 15 min), liquid smoke (0.50%, v/v) and freezing (−80 °C, overnight) was used to eliminate Listeria monocytogenes in BHI broth, raw and smoked trout. The bactericidal effect of liquid smoke solutions (L9 and G6), HHP and their combinations was evaluated against L. monocytogenes LO28, EGD-e and 10403S and further continued with the most resistant strain (10403S) to the combined treatment. For first time, a synergistic effect of liquid smoke and HHP was observed and was further enhanced by freezing prior to HHP. The effect of HHP and liquid smoke, prior to freezing was highest in BHI compared to raw and smoked trout. A major synergistic effect of HHP, liquid smoke and freezing was observed, reaching a 5.48 or 1.93 log CFU/g reduction when smoked or raw trout was used respectively. Furthermore, high injury levels occurred, among treatments reaching up to 55.98%

Oxidative stability of previously frozen ostrich Muscularis iliofibularis packaged under different modified atmospheric conditions

This study investigated the aptness of modified atmospheric packaging (70:30, O2:CO2 (O-MAP); 70:30, N2:CO2 (N-MAP)) and traditional overwrap (control) for previously frozen ostrich steaks, stored at 4±1°C for 10days. The N-MAP showed the least oxidation, O-MAP the highest and the control moderate. The redness (CIE a*) decreased to 3.67±0.83 by day 10 in the O-MAP, the N-MAP and control initially had lower values indicating slower oxidisation. The free carbonyl production was higher in the O-MAP than the N-MAP and control. TBARS remained relatively constant for the N-MAP and control, but increased to 9.70±3.26 (day 10) in the O-MAP. Drip loss (non-cumulative), was initially high (5-6%) for N-MAP and control, followed by a decrease on day 2 (2%) that increased to day 10 (4-6%). In conclusion, the traditional overwrap was not suited; N-MAP holds potential under a true anoxic atmosphere whilst O-MAP was limited by protein and lipid oxidation. © 2011 The Authors. International Journal of Food Science and Technology © 2011 Institute of Food Science and Technology.Articl

Impact of freezing and thawing on the quality of meat: Review

This comprehensive review describes the effects of freezing and thawing on the physical quality parameters of meat. The formation of ice crystals during freezing damages the ultrastructure and concentrates the solutes in the meat which, in turn, leads to alterations in the biochemical reactions that occur at the cellular level and influence the physical quality parameters of the meat. The quality parameters that were evaluated are moisture loss, protein denaturation, lipid and protein oxidation, colour, pH, shear force and microbial spoilage. Additionally mechanisms employed to mitigate the effects of freezing and thawing were also reviewed. These include the use of novel methods of freezing and thawing, ante and post mortem antifreeze protein inclusion and vitamin E supplementation, brine injection and modified atmospheric packaging. © 2012 Elsevier Ltd

Meat quality comparison between fresh and frozen/thawed ostrich M. iliofibularis

A pairwise comparison of the meat quality between fresh and frozen/thawed Musculus iliofibularis was conducted. Thirty-two (16 left; 16 right) muscles were collected and allocated to two treatments: fresh and frozen/thawed. Frozen vacuum-packed samples were stored for 1. month at -20. °C before thawing. The fresh samples had higher pH (P< 0.05), water binding capacity (P< 0.05), CIE L* (P< 0.0001), CIE a* (P< 0.05) and Chroma values (P< 0.05) than the frozen/thawed samples, indicating the fresh samples were bright red in appearance and had minimal exudate. The frozen/thawed samples lost 5.09 ± 0.21% moisture during thawing and had a greater drip loss (P< 0.0001) and shear force (P< 0.001). No differences were obtained with regard to cooking loss, CIE b*, hue and TBARS. Protein oxidation (mM carbonyls/mg protein) was lower (P< 0.05) in the frozen/thawed samples, which was attributed to the higher (P< 0.0001) protein concentration negating the higher (P< 0.001) carbonyl content. Industrial freezing and thawing regimes negatively affected the quality of ostrich meat. © 2012 Elsevier Ltd

Protein and lipid oxidative stability of fresh ostrich M. Iliofibularis packaged under different modified atmospheric packaging conditions

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Protein and lipid oxidative stability of fresh ostrich M. Iliofibularis packaged under different modified atmospheric packaging conditions

This study investigated the aptness of modified atmospheric packaging (70:30, O:CO (O-MAP); 70:30, N:CO (N-MAP)) and traditional overwrap (control) for fresh ostrich steaks, stored at 4 ± 1 °C for 10 days. N-MAP showed the least oxidation, O-MAP the highest and the control moderate. Myoglobin (CIE a) was gradually oxidised in all packaging atmospheres, but the O-MAP oxidised at the slowest rate, remaining significantly more bloomed from day 0 (17.86 ± 1.17) to 8 (9.78 ± 1.12). Free carbonyls were constant in all packaging environments. TBARS remained constant for the N-MAP (2.39 ± 0.21 mg MDA/kg meat) and the overwrap (3.06 ± 0.29 mg MDA/kg meat), but the O-MAP increased significantly (9.96 ± 1.02 mg MDA/kg meat) to day 10. The pH increased in the control but remained constant in the MAP treatments. The control also showed the greatest drip loss (>5%). The success of MAP application to ostrich will depend on the ability of the consumer to detect the by-products of lipid oxidation

Oxidative stability of previously frozen ostrich Muscularis iliofibularis packaged under different modified atmospheric conditions

This study investigated the aptness of modified atmospheric packaging (70:30, O:CO (O-MAP); 70:30, N:CO (N-MAP)) and traditional overwrap (control) for previously frozen ostrich steaks, stored at 4±1°C for 10days. The N-MAP showed the least oxidation, O-MAP the highest and the control moderate. The redness (CIE a*) decreased to 3.67±0.83 by day 10 in the O-MAP, the N-MAP and control initially had lower values indicating slower oxidisation. The free carbonyl production was higher in the O-MAP than the N-MAP and control. TBARS remained relatively constant for the N-MAP and control, but increased to 9.70±3.26 (day 10) in the O-MAP. Drip loss (non-cumulative), was initially high (5-6%) for N-MAP and control, followed by a decrease on day 2 (2%) that increased to day 10 (4-6%). In conclusion, the traditional overwrap was not suited; N-MAP holds potential under a true anoxic atmosphere whilst O-MAP was limited by protein and lipid oxidation. © 2011 The Authors. International Journal of Food Science and Technolog