Effects of polyethylene film wrap on cooler shrink and the microbial status of beef carcasses Guilherme S.L. Sampaio a, ⁎, Sérgio B. Pflanzer-Júnior b , Roberto de O. Roça c , Leandro Casagrande d , Elaine A. Bedeschi e , Carlos R. Padovani f , Giulianna Z. Miguel g , Carolina T. Santos g , Lucio V.C. Girão h , Zander B. Miranda a , Robson M. Franco a a Universidade Federal Fluminense — UFF, Faculdade de Veterinária, Rua Vital Brazil Filho, no 64, CEP 24230-340 Niterói, Rio de Janeiro, Brazil b Universidade Estadual de Campinas — UNICAMP, Faculdade de Engenharia de Alimentos — FEA, Rua Monteiro Lobato, no 80, CEP 13083-862 Campinas, São Paulo, Brazil c Universidade Estadual Paulista — UNESP, Faculdade de Ciências Agronômicas — FCA, Rua José Barbosa de Barros, no 1780, CEP 18610-307 Botucatu, São Paulo, Brazil d Fiscal Federal Agropecuário, Ministério da Agricultura Pecuária e Abastecimento — MAPA, Brazil e Centro Universitário da Fundação Educacional de Barretos — UNIFEB, Faculdade de Engenharia de Alimentos, Avenida Professor Roberto Frade Monte, no 389, CEP 14783-226 Barretos, São Paulo, Brazil f Universidade Estadual Paulista — UNESP, Instituto de Biociências — IBB, Distrito de Rubião Jr., s/n, CEP 18618-970 Botucatu, São Paulo, Brazil g Universidade Estadual Paulista — UNESP, Faculdade de Medicina Veterinária e Zootecnia — FMVZ, Distrito de Rubião Jr., s/n, CEP 18618-970 Botucatu, São Paulo, Brazil h Universidade Federal de Uberlândia — UFU, Faculdade de Medicina Veterinária — FAMEV, Avenida Pará, no 1720, CEP 38400-902 Uberlândia, Minas Gerais, Brazil abstract article info Article history: Received 7 February 2014 Received in revised form 8 August 2014 Accepted 20 October 2014 Available online 23 October 2014 Keywords: Bos indicus Carcass chilling Plastic film covering Weight loss Hygiene indicators Petrifilm The present study evaluated the use of polyethylene film wrapping of beef half carcasses and its effects on cooler shrink, cooling characteristics and microbial status of the half carcasses. Film wrapping reduced cooler shrink by 55.2%, 43.1%, 36.0% and 30% after 24, 48, 72 and 96 h of cooling, respectively, compared to the unwrapped half carcasses, whereas the surface water activity showed no significant differences among the time periods. The wrapped half carcasses had a lower cooling rate and higher surface and internal temperatures. The highest values of the aerobic mesophiles, Staphylococcus aureus and Enterobacteriaceae were found in the half carcasses wrapped in film. No significant differences were found in the values of Escherichia coli. The polyethylene film was effective in reducing cooler shrink; however, it caused a delay in cooling, thereby enabling greater microbial occurrences and counts and impairing the hygienic and sanitary conditions of the carcasses, which may be an impediment to the practical application of this technology. © 2014 Elsevier Ltd. All rights reserved. 1. Introduction Brazil is the second largest producer and largest exporter of beef worldwide, and in 2013, Brazil accounted for over 20% of the world trade by exporting 18.5% of the 9.67 million tons of beef produced throughout the year (USDA-FAS, 2014). However, the preservation of this position is subject to the continuance of scientific and technological innovations in all sectors of the supply chain (Ferraz & Felicio, 2010). Beef is one of the main foods involved in the incidence of zoonoses and food-borne outbreaks in humans (EFSA, 2013a,b). The most impor- tant pathogens are Escherichia coli O157:H7, E. coli STEC non-O157 and Salmonella spp., which are present in the gastrointestinal tract of cattle and may be transferred to the carcass during slaughter (Buncic et al., 2014; Duffy, Burgess, & Bolton, 2014; EFSA, 2013b). Indicator bacteria are used in slaughterhouses and meat-processing facilities during the assessment and validation process of the Hazard Analysis and Critical Control Points (HACCP) system. Although the correlation of indicator bacteria with the prevalence or level of pathogens has not been con- firmed, indicator bacteria suggest the possibility of pathogen occurrence because they indicate hygienic conditions and fecal contaminations (Milios, Drosinos, & Zoiopoulos, 2014). Fast chilling and maintenance of the cold chain are among the primary approaches used to control microbial growth, delay deteriora- tion and extend beef shelf life. Carcass chilling is considered a critical control point in HACCP systems because of its capacity to reduce bacte- rial counts through thermal and osmotic stress effects that occur with the reduction of temperature and water activity (Milios et al., 2014; Zhou, Xu, & Liu, 2010). However, the slaughter and processing industries may experience significant losses during chilling as a result of the depreciation process ‘cooler shrink’, which is characterized by water loss from dripping, tissue exudation and surface evaporation that results in carcass weight loss and lower beef cut yield. Surface desiccation and color deterioration may also occur, and they impair shelf life and consumer acceptability (Savell, Mueller, & Baird, 2005; Smith & Carpenter, 1973). In Brazil, recent studies on beef carcasses Meat Science 100 (2015) 164–170 ⁎ Corresponding author at: Rua Vital Brazil Filho, no 64, Bairro Vital Brazil, CEP 24230- 340 Niterói, Rio de Janeiro, Brazil. Tel.: +55 21 2629 9529; fax: +55 14 9 8176 4576. E-mail addresses: guilhermesampaio@id.uff.br, guilhermeslsampaio@yahoo.com.br (G.S.L. Sampaio). http://dx.doi.org/10.1016/j.meatsci.2014.10.018 0309-1740/© 2014 Elsevier Ltd. All rights reserved. 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