Surface pasteurisation of poultry meat using steam at atmospheric pressure C. James a, * , E.O. G oksoy a , J.E.L. Corry b , S.J. James a a MAFF Advanced Fellowship in Food Process Engineering, FRPERC, University of Bristol, Churchill Building, Langford, Bristol BS40 5DU, UK b Department of Clinical Veterinary Science, Division of Food Animal Science, University of Bristol, Churchill Building, Langford, Bristol BS40 5DU, UK Received 15 October 1999; accepted 22 February 2000 Abstract The eects of various steam treatments on the appearance, shelf-life and microbiological quality of chicken portions were in- vestigated. Application of steam at atmospheric pressure (100°C for 10 s) on naturally contaminated chicken breast portions re- sulted in a 1:65 log 10 cfu cm 2 (S.D. 1.06) reduction in the numbers of total viable bacteria. However, in comparison with untreated controls, this treatment did not extend the shelf-life. Steam treatment for up to 10 s on chicken portions inoculated with a nalidixic acid resistant strain of Escherichia coli serotype O 80 resulted in a maximum reduction of 1:90 log 10 cfu cm 2 (S.D. 0.63). Overall, results indicate that significant reductions in microbiological numbers can be achieved on chicken meat using steam. However, such reductions have little eect on the shelf-life of portioned chicken. Ó 2000 Elsevier Science Ltd. All rights reserved. Keywords: Decontamination; Steam; Poultry; Escherichia coli; Shelf-life 1. Introduction The number of incidences of food poisoning are in- creasing throughout the world. Many of these outbreaks have been associated with red and white meats and meat products. In the UK in 1994 over 40% of frozen and 33% of chilled poultry was found to be contaminated with salmonella (Parliamentary Oce of Science and Technology, 1997). Outbreaks associated with salmo- nella resulting from the consumption of undercooked poultry, or cross-contamination from raw poultry, are of considerable concern. Substantially reducing, if not totally eliminating, pathogens from raw poultry could significantly reduce the incidence of food poisoning. Studies on red meat have shown that the deep tissues of red meat carcasses are intrinsically sterile (Gill, 1979, 1980). It is not unreasonable to assume that the same applies to healthy poultry. During processing, especially defeathering and evisceration, bacteria are spread from the feathers and intestinal tract to the surface of the carcass. Thus, a process that could consistently reduce the numbers of pathogenic microorganisms on the sur- face of poultry without changing the nature of the sur- face would be of considerable use to the industry. James and James (1997) have reviewed surface de- contamination systems for red meat and G oksoy (1999), those specifically for poultry. Many chemical treat- ments, including organic acids, sorbates, chlorine, phosphates, bacteriocins and ozone, have been investi- gated. Chlorine has traditionally been used in wash water and the use of trisodium phosphate (TSP) has been approved in the US, and some EU countries on a case-by-case basis. However, in general, the industry is not keen to add chemicals to raw poultry and is looking at alternatives such as heat based processes. To achieve success, a heat based decontamination system needs to raise the surface temperature rapidly to a value (>70°C) at which pathogens are killed. The heat must then be quickly removed to prevent it penetrating into the muscle and denaturing the proteins, i.e. cooking the meat. One such method of rapidly heating surfaces is the application of steam. The main advantage of using steam is the large amount of heat transferred to the food when steam condenses, which increases the surface temperature rapidly. Steam at 100°C has a greater heat capacity than the same amount of water at that tem- perature (James & James, 1997). In addition steam has the ability to penetrate cavities, crevices and feather Journal of Food Engineering 45 (2000) 111–117 www.elsevier.com/locate/jfoodeng * Corresponding author. Tel.: +44-117-928-9239; fax: +44-117-928- 9314. E-mail address: chris.james@bristol.ac.uk (C. James). 0260-8774/00/$ - see front matter Ó 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 2 6 0 - 8 7 7 4 ( 0 0 ) 0 0 0 4 8 - 0