Growth of Salmonella Typhimurium DT104 at 30°C is not affected by anatomical location on the chicken carcass.
Development of models for growth of Salmonella in the chicken food matrix is time-consuming and expensive. The current study was undertaken to examine growth of Salmonella on different anatomical locations of the chicken carcass. The purpose was to determine whether anatomical  location should be included as an independent variable in predictive models for chicken. Eleven anatomical locations were studied: skin (wing, breast, drumstick, and thigh), meat surface (wing, breast, drumstick, and thigh), and meat interior (breast, drumstick, and thigh). Background microflora,  pH, and growth (lag time, λ; growth rate, μ; and time for a 3-log increase, t(3)) at 30°C for a small inoculum size (0.92 ± 0.30 log per portion) of Salmonella Typhimurium DT104 were examined. Four or six replicate storage trials were conducted per  anatomical location (n = 46 growth curves). Portion sizes were 1.12 ± 0.17 g (mean ± standard deviation) for meat and 0.25 ± 0.08 g for skin. A two-phase linear model was used to determine λ and μ. The effect of anatomical location on dependent variables  was assessed by one-way analysis of variance. pH values differed (P < 0.001) among anatomical locations, with skin (6.86 ± 0.20). dark meat (6.39 ± 0.20) . white meat (5.97 ± 0.20). Background microflora (4.32 ± 1.66 log per portion) was variable and not  affected (P > 0.05) by anatomical location. Likewise, λ (1.90 ± 0.75 h), μ (0.648 ± 0.120 log/h), and t(3) (6.71 ± 0.82 h) at 30°C were not affected (P > 0.05) by anatomical location. Although there were differences in  pH among anatomical locations, these differences were not sufficient to affect growth of Salmonella Typhimurium DT104 at 30°C. If this observation holds for other storage conditions and strains, then anatomical location does not need to be included as an independent variable in  predictive models for chicken. This would save significant time and money for the predictive microbiologist.
U.S. Department of Agriculture, Agricultural Research Service, Chemical Residue and Predictive Microbiology Research Unit, Room 2111, Center for Food Science and Technology, University of Maryland, Eastern Shore, Princess Anne, Maryland 21853, USA. thomas.oscar@ars.usda.gov
Thomas P
TP
Oscar
D000818:Animals; D002645:Chickens / Q000033:anatomy & histology / Q000382:microbiology*; D015169:Colony Count, Microbial; D005506:Food Contamination / Q000032:analysis*; D005516:Food Microbiology; D006358:Hot Temperature; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008954:Models, Biological; D011237:Predictive Value of Tests; D012486:Salmonella typhimurium / Q000254:growth & development*