Microbiological Assessment of Broiler Compound Feed Production as Part of the Food Chain—A Case Study in a Romanian Feed Mill

Compound feed and the raw materials used in their production are potential vectors of microbiological contamination in the food chain. The purpose of this study was to microbiologically asses raw materials (maize, wheat, soybean meal, and sunflower meal), and broiler compound feed (starter, grower, and finisher) from a representative feed mill in Romania; the microbiological contaminants that were analyzed were yeasts and molds, Salmonella spp., Escherichia coli , and Clostridium perfringens . Our study occured during the years 2019 and 2020; in 2019, 191 samples of raw materials and 360 samples of compound feed were analyzed and in 2020, 143 samples of raw materials and 241 samples of compound feed were analzyed. Among the tested samples of raw materials, the mean values of the yeasts and molds for maize, wheat, soybean, and sunflower meal were 1.3 × 10 3 , 9.5 × 10 2 , 6.4 × 10 2 , and 7.4 × 10 2 cfu/g in 2019 and 1.5 × 10 3 , 1.0 × 10 3 , 5.2 × 10 2 , and 7.1 × 10 2 cfu/g in 2020. In the analyzed compound feed samples, the mean amounts for the starter, grower, and finisher were 5.9 × 10 2 , 4.2 × 10 2 , and 4.2 × 10 2 cfu/g in 2019 and 5.3 × 10 2 , 6.5 × 10 2 , and 5.8 × 10 2 cfu/g in 2020. Potentially toxigenic fungi from Aspergillus , Penicillium , and Fusarium genera have been identified as the most common in all of the samples. In the raw materials, in both years the highest numbers of Aspergillus -positive samples were recorded: 66.6% in 2019 and 100% in 2020 for the maize samples, 50% in 2019 and 75% in 2020 for the wheat samples, 76% in 2019 and 87.5% in 2020 for the soybean meal samples and 71.4% in 2019 and 100% in 2020 for the sunflower meal. In the starter compound feed, the Aspergillus genera was prevailing in 2019 (46.6%), while in 2020, the species of the Penicillium and Cladosporium genera were identified in the majority of the samples (50%); for the grower and finisher compound feed, the Aspergillus genera was predominantly identified in 2019 (60% and 72.2% of the samples, respectively) and 2020 (61.5% and 46.6%, respectively). All of the results of the bacteriological analysis for determining the contamination with Salmonella spp., E. coli , and Clostridium perfringens were negative. Based on the results obtained in this study, monitoring and analysis of microbiological hazards in a feed mill will help to control and prevent contamination and have a direct impact on food safety.