first_page settings Order Article Reprints Open AccessArticle Enterobacteriaceae in Sewage Sludge and Digestate Intended for Soil Fertilization by Angelina Wójcik-Fatla 1,* [ORCID] , Ewelina Farian 1 [ORCID] , Katarzyna Kowalczyk 1 [ORCID] , Jacek Sroka 2 [ORCID] , Piotr Skowron 3 [ORCID] , Grzegorz Siebielec 4 [ORCID] , Jolanta Małgorzata Zdybel 2 [ORCID] , Tamara Jadczyszyn 3 [ORCID] and Tomasz Cencek 2 [ORCID] 1 Department of Health Biohazards and Parasitology, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland 2 Department of Parasitology and Invasive Diseases, National Veterinary Research Institute-State Research Institute, Aleja Partyzantów 57, 24-100 Puławy, Poland 3 Department of Plant Nutrition and Fertilization, Institute of Soil Science and Plant Cultivation State Research Institute, Czartoryskich 8, 24-100 Puławy, Poland 4 Department of Soil Science Erosion and Land Protection, Institute of Soil Science and Plant Cultivation-State Research Institute, Czartoryskich 8, 24-100 Puławy, Poland * Author to whom correspondence should be addressed. Pathogens 2024, 13(12), 1056; https://doi.org/10.3390/pathogens13121056 Submission received: 19 October 2024 / Revised: 26 November 2024 / Accepted: 28 November 2024 / Published: 30 November 2024 Download keyboard_arrow_down Browse Figure Versions Notes Abstract Substances of organic origin are seeing increasing use in agriculture as rich sources of nutrients for plants. The aim of this study was to determine the microbiological contamination of sewage sludge and digestate to assess their safe use as fertilizers in Poland. The assessment of microbial soil, sewage sludge and digestate contamination was based on the total number of mesophilic bacteria and Gram-negative bacteria from the Enterobacteriaceae family. The presence of Escherichia coli and Salmonella spp. was identified via culture and the presence of Enterobacteriaceae species was determined via biochemical and molecular methods. In laboratory conditions, the survival of E. coli in soil fertilized with sewage sludge or digestate inoculated with a reference strain was determined. The average concentration of Enterobacteriaceae in soil, sewage sludge and digestate samples was 1.1 × 104 CFU/g, 9.4 × 105 CFU/g and 5.6 × 106 CFU/g, respectively. Escherichia coli was detected in all sample types. From the soil samples, Serratia, Enterobacter, Pantoea, Citrobacter and Pseudomonas genera were identified the most frequently, while in sewage sludge and digestate, E. coli was predominant. Based on the results of our laboratory experiment, it can be concluded that after three weeks, fertilization with organic waste in acceptable doses does not significantly increase soil contamination with Enterobacteriaceae.