Gonzales-Barron, UrsulaCadavez, VascoButler, Francis2018-05-092018-05-092013Gonzales-Barron, Ursula A.; Cadavez, Vasco; Butler, Francis (2013). An alternative framework to conduct inferential statistics for low microbial counts in foods: the poisson-gamma regression. In Proceedings of International Conference on Food and Biosystems Engineering - FaBE 2013. Skiathos Island, Greece. Vol. 1, p. 522-531. ISBN 978-960-9510-09-7978-960-9510-09-7http://hdl.handle.net/10198/17612The objective of this article was to compare four Poisson-gamma regression models to assess the effect of chilling on the concentration of coliforms from beef carcasses. A total of 600 carcasses were sampled before and after chilling at eight large Irish abattoirs, and the total coliforms were determined. With a coded variable (pre-chill/post-chill) as treatment, and extracting the variability of batches nested in abattoirs, random-effects models confirmed that chilling had a decreasing effect on the overall recovery of coliforms. Furthermore, the expected coliforms concentrations on pre-chill and post-chill carcasses were estimated on a CFU/cm2 scale, as well as their between-batch variability. This study introduced an alternative conceptual framework that can find interesting applications in stochastic risk assessment and in the design of more efficient sampling plans.engNegative binomialChillingColiformsCarcassconference object