The effects of stunning methods on product qualities in force-fed ducks and geese. 1. Carcass downgrading and meat quality

Abstract

This study investigated the effects of various stunning methods on the quality of carcass and meat in ducks and geese force-fed for the production of French ' foie gras'. The ducks (n 5 30 per group) were stunned with one of the following techniques: electrical stunning in a water bath (50 Hz AC, 130 mA, 4 s), head-only electrical stunning (50 Hz AC, 600 mA, 4 s), mechanical stunning (captive bolt) and controlled atmosphere stunning (CAS: phase 1, CO 2 (40%)-O 2 (30%)-N 2 (30%), for 2 min followed by phase 2, CO 2 . 85% in air, for 2 min). The same methods (except head-only stunning which was not applied) were used in geese (n 5 40 per group). During the first 5 min after slaughter, the stunning techniques that did not kill the animals were associated with a high incidence of head movements (mechanical and electrical head-only stunning), convulsions and convulsive wing flapping (mechanical stunning), in both species. Consequently, the rate of post-mortem pH fall in breast muscle was enhanced and the meat was paler when measured at 24 h or 6 days post mortem ( L*, a*, b* coordinates). In ducks, the animals stunned in the water bath showed the lowest bleeding efficiency, compared to the three other procedures. In geese, the mechanical stunning allowed the highest recovery of blood compared to the CAS and the water-bath methods. Meat texture assessed instrumentally and fluid losses during storage and processing were not affected by the stunning method in any species. Sensory analysis showed a higher score for bloody appearance of raw meat in ducks stunned with the methods that kill before neck cutting (water-bath and CAS). This effect was, however, not linked to the rate of bleeding. The sensory properties of cooked meat were not affected by the stunning method. In both ducks and geese, CAS was associated with the lowest rate of fractures of humeral bone but CAS-stunned geese showed the most engorged wing veins. Overall, these results show the positive effect of CAS on the appearance defects of carcass and meat of ducks and geese, and, on the contrary, they confirm the detrimental effects of water-bath stunning on these criteria. However, the incidences on meat sensory qualities were scarce.

Serbest Çiftlik Koşullarında Yetiştirilen Türk Yerli Kazlarında Cinsiyet ve Yaşın Et Kalitesi Üzerine Etkisi

“…Supporting the current result, similar L* value in male and female birds were reported by numerous authors for chicken 27,41 and for quail 48 . On the other hand, meat lightness values of the current study (40.15-40.59 for breast meat, 43.72-44.20 for thigh meat) were comparable with previous reports for geese meat 33,49 .…”

“…Supporting this result, Saláková et al 50 also reported significant influence of meat ultimate pH on meat redness. The redness values found in the current study (12.30-13.61 for breast meat, 9.79-10.38 for thigh meat) were lower than those reported by Okruszek et al 33 for Polish geese and by Fernandez et al 49 for French Landes grey breed. This difference indicate darker meat colour in Polish geese and French Landes grey breeds, and might be explained by difference in breed of geese, slaughter age and feeding system between studies.…”

Proximate Composition, Color and Nutritional Profile of Raw and Cooked Goose Meat with Different Methods

“…However, these results were higher than the reports of 19.2–20.5 by Fernandez et al . () for geese. The differences in cooking losses between the researches could be attributed to the differences in the cooking conditions, pH of the meat, muscle used and various other factors, which are often not reported.…”

Qualité des carcasses et de la viande des palmipèdes gavés

“…En revanche, la résistance de la viande crue à une force de compression augmentait avec la durée d'attente sur quai (47,8 vs 37,8 N/cm 2 ). Fernandez et al (2010) ont comparé différentes techniques de narcose lors de l'abattage d'oies et de canards mulards gavés : électronarcose en bain (50 Hz en courant alternatif, 130 mA, 4 s), électronarcose bitemporale (50 Hz en courant alternatif, 600 mA, 4 s), étourdissement mécanique avec un pistolet à tige perforante et étourdissement en atmosphère modifiée (phase 1, 40% CO 2 -30% O 2 -30% N 2 ) pendant 2 min suivie de la phase 2, CO 2 > 85% dans l'air pendant 2 min). Chez les deux espèces, l'étourdissement en atmosphère modifiée était associé à une vitesse de chute du pH post-mortem plus lente et à une moindre accumulation d'acide lactique dans le magret.…”