Salmonella on Turkey Skin

March 2015

According to the 2013 USDA Food Safety and Inspection Service (FSIS) data, Salmonella prevalence in ground turkey is 15%, which is about six times higher than that on turkey carcasses (2.3%). Identifying potential sources and predictors of Salmonella in ground turkey is therefore important to the turkey industry for controlling and preventing contamination, and releasing ground turkey into commerce.

For ground turkey production, various types of turkey meat, along with skin as a source of fat, are used. It is well known that Salmonella is present on turkey skin. Therefore, skin can serve as a route of Salmonella entry to ground products. Since characteristics of skin on various parts of turkey carcasses are different, we expect variation in Salmonella contamination levels, depending on the part. Common skin parts used as sources of fat in ground turkey production include those from drumsticks, thighs, and wings.

In our previous research work, prevalence and mean numbers of Salmonella on turkey neck skin were 42% and 2.5 log MPN/sample, respectively. Although, neck skin is not currently used in ground turkey production, it may serve as a source of cross contamination with Salmonella. The goal of this study was to determine the prevalence and numbers of Salmonella on skin of turkey drumsticks, thighs, and wings collected at post-chill in a commercial turkey processing plant.

Twenty turkey flocks expected to be highly contaminated with Salmonella based on results of boot-sock tests were selected for the study. From each flock, fifteen carcasses were collected at the exit of the chiller. A drumstick, thigh, and wing from the right half of each carcass was removed and individually placed in sterile bags. Skin from each sample was combined with 300 ml of buffered peptone water and stomached for 2 minutes. A 3-tube, 3-dilution Most Probable Number (MPN) method was used to quantify Salmonella. Primary enrichment and delayed second enrichment were done to recover injured Salmonella.

To date, skin samples from 13 flocks have been analyzed. There was a significant difference (P ≤ 0.05) in Salmonella prevalence in skin of drumsticks (13.3%), thighs (16.4%), and wings (23.6%). The mean numbers of Salmonella/g of skin were 0.22 MPN/g (drumstick), 0.18 MPN/g (thigh), and 0.36 MPN/g (wing). However, these means were not significantly different (P > 0.05).

Based on preliminary results, turkey wing skin is more frequently contaminated with Salmonella than are thigh and drumstick skins. If this continues to be the case through completion of the study, processors may want to reduce the use of wing skin in ground turkey production in an attempt to reduce the number of Salmonella in the final product.