Numbers ofSalmonella recovered by sponge or low volume whole carcass rinse sampling of inoculated commercial turkey carcasses

Abstract

Processed turkey carcasses are sampled for Salmonella via sponge sampling, whereas broilers are sampled via whole carcass rinses. Because different sampling methods have been reported to produce different results, sponge sampling and whole carcass rinsing (WCR) were performed on turkey hen carcasses inoculated with a known amount of nalidixic acid-resistant Salmonella enterica serovar Enteritidis. Five turkey hen carcasses were collected from the shackle line in a commercial processing plant in each of 4 replicate trials. Carcasses were placed in a cooler with a small amount of ice and transported to the laboratory for approximately 1.5 h. Salmonella inoculum was applied by spreading 0.5 mL on the back and 0.5 mL on the thigh. After 10 min, the carcasses were sampled via a premoistened 4×8-cm sponge, swiping 10 times vertically and 10 horizontally on the back, and then repeating the same sequence on the thigh using a 10×5-cm template. After sponge sampling carcasses were placed in a clean plastic bag, 200 mL of buffered peptone was added, and bags were manually shaken for 60 s for a low volume whole carcass rinse (WCR). Liquid from stomached sponges and from WCR rinsate was serially diluted in 0.85% saline and plated onto Brilliant Green agar with sulfapyridine containing 200 ppm of nalidixic acid. Plates were incubated at 37°C for 24 h and colonies indicative of Salmonella were counted and transformed from cfu/mL to log cfu/cm2. The low volume WCR recovered significantly more Salmonella than sponge sampling in trial 3 (log 3.1 vs. 2.3, respectively) and trial 4 (log 3.1 vs. 2.2, respectively). No differences were observed in trials 1 and 2 due to sample method. Low volume WCR is equal to or more effective than sponge sampling for recovering inoculated Salmonella from turkey carcasses.