Consumer perceptions of meat quality and shelf-life in commercially raised broilers compared to organic free range broilers

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1 Consumer perceptions of met qulity nd shelf-life in commercilly rised roilers compred to orgnic free rnge roilers C.Z. ALVARADO 1 *, E. WENGER 2 nd S. F. O KEEFE 3 1 Texs Tech University, Box Luock, TX 79409, USA 2 Toulouse University, Frnce 3 Virgini Polytechnic Institute nd Stte University, Duck Pond Rd, Blcksurg, VA 24070, USA *christine.lvrdo@ttu.edu Keywords: free rnge; orgnic; shelf-life; sensory; tenderness Summry Consumers in the United Sttes re incresingly interested in oth free-rnge nd orgnic chicken. Therefore, the ojectives of this reserch were to compre eting qulity nd shelf-life of met from orgnic free rnge roilers to met from commercilly rised roilers. No significnt differences in rest fillet tenderness or proximte composition were noted etween the two tretments. Free-rnge chicken rests were significntly lrger (153 g) thn commercil chicken rests (121 g). Brest fillets from the free rnge irds hd higher ph vlues (5.96 vs respectively) nd were drker (49.14 vs , respectively) thn fillets from the commercilly rised irds. Initil TBARS (dy 0) were significntly higher for the commercilly rised roiler rest fillets (4.96 vs mg mlonldehyde/kg), ut y dy 3 of refrigerted storge the level of oxidtion ws similr. Free rnge fillets hd significntly higher APC nd coliform counts nd exhiited signs of spoilge erlier thn commercil fillets. Consumers evluted rest fillets, using rnking test (1-lest intense to 5-most intense) nd the resultnt dt ws nlyzed using Kruskl-Wllis. Consumers found no difference in fillet juiciness, tenderness or flvour (P>0.05). Commercil rest fillets, however, were preferred over the free-rnge fillets (P<0.05). Trined pnellists evluted drums finding no difference in tenderness or flvour, ut met from free rnge irds ws juicier nd hd stronger ttchment of the met to the one. Commercil nd free-rnge chicken hd mny similrities in met qulity nd sensory ttriutes, ut met from free-rnge poultry hd shorter shelf life thn met from commercilly rised chickens. Introduction All poultry ws rised outdoors until round the 1950s, when poultry producers egn to rise irds inside for protection from predtors, disese control, nd to integrte their control mesures to produce more uniform product. Tody, we cll this indoor production commercil poultry production. Alterntive poultry production systems such s orgnic nd free rnge orgnic re mostly outside production system nd hve creted niche mrket in the poultry industry. Currently, there is quite lot of confusion with consumers etween the terms orgnic nd free rnge. Often, consumers use these terms interchngely. In the USA, Certified Orgnic poultry met must go though rigorous certifiction process s descried y USDA guidelines (USDA Orgnic Stndrds). The certifiction process cn tke months nd is often suject to multiple on-site inspections to continue certified orgnic stndrds. The cost ssocited with orgnic poultry met is often very high due to the cost nd vilility of orgnic grin nd other ingredients used in feed. Currently there re very few mjor poultry processors (~2 specificlly) in the USA tht produce orgnic poultry met in mss production. Most re smll scle orgnic nd free rnge processors which process the irds mostly y hnd with smll pilot scle equipment, hve n exemption sttus (limited USDA inspection) nd cn only sell the orgnic poultry met with-in stte lines. On the other hnd, the USDA definition for free rnge is just simply llowing the irds ccess to the outdoors. There re currently no other stndrds for free rnge chickens. Most ll smll processors tht sell free rnge chickens re lso certified orgnic for mrketing purposes. The sle of orgnic food is growing t rte of t lest 20% which mkes it the fstest growing griculturl mrket (Orgnic Consumer Trends, 2001). Most poultry processors tht rise roilers for the orgnic mrket lso use the lel free rnge for incresed mrketing. These lterntive poultry 257

2 production systems offer opportunities for smll scle producers to infiltrte niche mrket nd to provide specilty product for consumers. Most rticles deling with orgnic nd free rnge poultry re from Europe nd del strictly with the production of these pstured poultry systems (how to, disese control, feeding nd met qulity of orgnic nd free rnge orgnic production of chickens utilizing met from ctul orgnic nd free rnge production systems). The Europen production system is much more dvnced for free rnge production when compred to the USA. There re very few reserch studies in the USA regrding these methods. It is importnt for processors nd consumers tht unised reserch detiling consumer perceptions re determined nd ctul met qulity comprisons re conducted to determine differences etween met purchsed form commercil processor nd met purchsed from n orgnic nd free rnge producer. Therefore, the ojective of this study ws to determine ojective met qulity, composition, nd sensory differences mong commercil nd free-rnge orgnic roiler rest fillets. Mterils nd methods The commercil irds were 42 dys of ge efore slughter nd the orgnic free rnge irds were 10 weeks prior to slughter. A totl of 200 roiler rest fillets in 2 trils were e otined from commercil processor nd n orgnic free rnge processor. The rest fillets rrived t the Texs Tech University Met Lortory within 24 hours of slughter. At 24 hours post-mortem, the fillets were weighed, nd colour (Minolt colorimeter) nd ph (IQF Scientific proe nd meter) dt were collected on ll the smples. Hlf of the rest fillets from ech tretment (commercil nd free rnge orgnic) will e cooked in convection oven ccording to the procedures of Sms (1990) for cook loss determintion. Following cook loss determintion, cudl portion of the cooked smple ws nlyzed for cooked totl moisture ccording to stndrd oven dry methodology (AOAC, 1993). The remining crnil portion of the rest fillet ws nlyzed for tenderness with non-destructive rzor lde method (Cvitt et l., 2004). Since this method is non-destructive, the remining crnil portion of the fillet ws used for the sensory testing. Oxidtion (TBARS) ws determined in the smples from ech of the tretments on Dy 0 (24 hr post slughter) nd 4 (5 dys post slughter) ccording to Spnier nd Trylor (1991). Since differences in production method, especilly feed, cn result in different nutritionl components in the met, proximte nlysis of the roiler rest met from the 3 tretments ws lso determined in this study using AOAC methods (1993) to determine differences in protein (FP200 Leco Nitrogen nlyzer), ft (Bligh nd Dyer, 1982), sh (AOAC 1995), nd moisture. On the remining roiler rest fillets not used for the ove nlyses, microiologicl (APC nd coliforms) shelf-life dt ws conducted using Petri-film pltes. For the consumer sensory testing on the roiler rest fillets, n 8 point hedonic scle ws used to determine preference testing on tenderness, juiciness, flvour, nd overll preference on the commercil nd orgnic free rnge chicken rest fillets. A minimum of 60 consumer pnellists were used in this study. The legs were evluted y trined pnel of 6 memers. The memers were trined on flvour, tenderness, juiciness, nd ttchment of the met to the one. The dt will e sujected to the GLM procedure of SAS nd mens will e seprted using Duncn s Multiple Rnge Test. The sensory dt will e sujected to non-prmetric test (Kruskl- Wlis). A significnce level of P< 0.05 will e used to determine significnt differences. Results Tle 1 Qulity prmeters of commercil nd free rnge chicken rest fillets 1. Tretment Pre-cook Weight (g) Cook Loss (%) ph Tenderness Commercil Free Rnge Mens within column with different superscripts re different (P<0.05) (N) 258

3 Tle 2 Hunter colour vlues of commercil nd free rnge chicken rest fillets 1. Colour Tretment L* * * Commercil Free Rnge Mens within column with different superscripts re different (P<0.05) Tle 3 Proximte nlysis of commercil nd free rnge chicken roiler rest fillets 1. Tretment Protein (%) Ft (%) Ash (%) Commercil Free Rnge Mens within column with different superscripts re different (P<0.05) Tle 4 Oxidtion mesurements of the commercil nd free rnge chicken roiler rest fillets 1. TBARS (mg mlonldehyde/kg ft) Tretment Dy 0 Dy 3 Commercil Free Rnge Log CFU/g Free Rnge Commercil 0 APC Dy 4 APC Dy 6 Coliforms Dy 4 Coliforms Dy 6 Microorgnisms Figure 1 Shelf-life of commercil nd free rnge chicken rest fillets t Dys 4 nd 6 post slughter. 259

4 Discussion QUALITY PARAMETERS AND COLOUR VALUES Qulity prmeters including cook loss (%), ph, colour nd tenderness were evluted in this study to compre commercil chicken to orgnic free rnge chicken rest fillets (Tle 1). Pre-cook weights were significntly higher in the free rnge irds. In the USA, free rnge irds re slughtered round weeks of ge where commercil irds re slughtered 5-6 weeks of ge. Even though the free rnge irds re slower growing ird due to decresed feed efficiency, they re rised for longer period nd therefore hve lrger rest fillet compred to the commercil irds. Cook loss (%) nd tenderness of the rest fillets were similr indicting tht neither the commercil or orgnic free rnge irds lost significnt mount of moisture during cooking. However, the free rnge chicken rest fillets hd significntly higher ph nd lower L* vlue (Tle 2) indicting drker colour thn the commercil rest fillets. This drk fillet colour is expected with high ph. The free rnge rest fillets lso hd significntly more intense red colour (*) nd more intense yellow colour (*) thn the commercil chicken rest fillets. The differences in colour of the rest fillets from the orgnic free rnge irds my e due to feed differences. The commercil irds were fed diet sed on the NRC guidelines (NRC, 1994) while the free rnge irds were fed diets with similr NRC guidelines except the irds were fed certified orgnic feed. Free rnge irds were lso rised outdoors nd llowed ccess to grss nd other outdoor feed which could hve ffected rest colour. PROXIMATE ANALYSIS AND OXIDATION Protein (%), % ft nd % sh were similr for the free rnge nd commercil chicken rest fillets. Previous preliminry dt hs indicted tht there re no nutritionl differences etween free rnge nd commercil chicken rest met. However, even thought the percentges of the proximte nlyses (specificlly ft) re not significntly different there my e differences in the ftty cid profiles. Currently ftty cid profiles re eing nlyzed for oth commercil nd free rnge chickens used in this study to determine if ny differences exist. There were significnt differences in oxidtion (TBARS) levels on Dy 0 (24 hr post slughter) with the commercil rests hving higher oxidtion level thn the free rnge rests. This sme pttern ws noted in the trined sensory evlution with higher oxidtion or n incresed wrmer over flvour in the commercil rest fillets. Also, y Dy 4 there were no noticele differences in oxidtion. The differences t Dy 4 could e due to different ftty cid profile or higher vitmins nd minerls tht re ntioxidnt present in the feed or grsses ville to the free rnge irds. However, y Dy 4 (5 dys post slughter) the oxidtion levels were not significntly different etween the 2 tretments. This lck of difference is nturl occurrence following cooking of the roiler rest fillets nd extended storge times. SENSORY ANALYSES Sensory nlysis ws conducted on the commercil nd free rnge chicken rest fillets. However, no differences were found for the ttriutes: juiciness, tenderness, nd flvour. Differences were oserved in the overll preference of the chicken; the commercil chicken rest fillets were preferred over the free rnge chicken rest fillets ecuse the free rnge chicken rest fillets hd more grin-like flvour. Sensory nlysis ws lso conducted on the drums. Tenderness nd flvour were similr. However, the free rnge drums were juicier nd hd stronger ttchment to the one thn did the commercil chicken drums. SHELF-LIFE The microiologicl dt indicted tht the free rnge chicken rest fillets hd significntly higher APC counts on oth Dy 0 (24 post slughter) nd Dy 4 (Dy 5 post slughter) thn the commercil chicken indicting erlier spoilge. The free rnge chicken rest fillets lso hd significntly higher coliform vlues on oth Dy 0 nd Dy 4 thn did the commercil chicken rest fillets. These high APC nd coliform counts mye indictive of smll processors not hving s dequte microiologicl control methods compred to lrge commercil processors. 260

5 Conclusions Commercil nd free-rnge chicken hd mny similrities in met qulity nd sensory ttriutes, ut met from free-rnge poultry hd shorter shelf life thn met from commercilly rised chickens. References Assocition of Officil Anlyticl Chemists Officil methods nd of nlysis, 16th ed. Arlington, CA. Cvitt, L.C., G.W. Youm, J.S. Meullenet, C.M. Owens, nd R. Xiong Prediction of poultry met tenderness using rzor lde sher, Allo Krmer sher, nd srcomere length. J. Food Sci. 69(1). Christie, D Modifiction of Bligh nd Dryer. Cn. J. Biochem. Physiol. 37:911. Downes, F.P. nd K. Ito Compendium of methods for microiologicl exmintion of foods. 4th ed. Americn Pulic Helth Assocition, Wshington, D.C. Lohr, L Fctors ffecting interntionl demnd nd trde in orgnic food products. Economic Reserch Service USDA Ntionl Reserch Council, Nutrient Requirements of Poultry. Ninth Revised Edition. Ntionl Acdemy Press, Wshington, D.C. Sms, A. R Electricl stimultion nd high temperture conditioning of roiler crcsses. Poultry Sci. 69: SAS SAS/STAT User s Guide. Version 8.2, Sttisticl Anlysis Systems Institute, Inc., Cry, N.C. Spnier A.M. nd R.D. Trylor A rpid, direct chemicl ssy for the quntittive determintion of thiorituric cid rective sustnces in rw, cooked, nd cooked/stored muscle foods. J. Muscle Foods 2: