Automated Extraction and Analysis of Salmonella enterica From Ground Turkey and Kitchen Surfaces

Abstract

Salmonella enterica is a gram negative bacterium commonly associated with raw poultry and food borne illness. Evogen has developed a fully Automated Sample Preparation (ASP) instrument which was used to extract and purify DNA from ground turkey meat cultures and kitchen surface swabs. DNA purified on the ASP was then amplified using loop‐mediated isothermal amplification (LAMP). Five gram samples of fresh ground turkey were placed in 50 mL of culture media in sterile culture flasks, inoculated with S. enterica at 3800 cfu/mL and placed in a 37°C incubator for 24 hours. Kitchen surfaces which had been in contact with the fresh turkey were inoculated at 3800 cfu/mL and allowed to dry for 30 minutes. Swabs were used to sample surfaces and placed in 1 mL of culture media and cultured at 37°C for 24 hours. Following incubation, a 200 μl aliquot from each sample was placed in an ASP cartridge for DNA extraction and purification. DNA concentration was measured after extraction. 5.0μl of extracted DNA was then used for LAMP. The LAMP reactions were held at 65ºC for 30 minutes and an annealing curve was performed at 98–75ºC. All culture and swab samples extracted on the ASP provided positive results via LAMP within 12 minutes. The mean concentration of DNA recovered from the samples was 21.0 ng/μl ± 2.8 ng/μl. This new sample preparation system provides high quality DNA that was rapidly detectable by LAMP.Private Funding