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The aim of this study was to evaluate the physicochemical composition and antibacterial activity of Brazilian propolis extracts from different types, concentrations, and extraction solvents and from different regions in Brazil. A total of 21 samples were analyzed, comprising 14 samples from Apis mellifera (12 green, 1 brown, and 1 red) and 7 samples from stingless bees (3 mandaçaia, 2 jataí, 1 hebora, and 1 tubuna). The analyses performed were dry extract, total phenolic content (TPC) and antioxidant activity (DPPH and ABTS). The antibacterial activity was performed by Determination of Minimal Inhibitory Concentration (MIC) and Minimal Bactericidal Concentration (MBC). The results showed that very low levels of phenolic compounds and antioxidant activity decreased the antimicrobial activity of the propolis extracts from tubuna and jataí. However, there was no correlation between the increase in propolis concentration in the extract, and the increase in antimicrobial activity. The highest TPC and antioxidant activity was obtained for green propolis extract made with 70% raw propolis that presented similar antibacterial activity to the samples formulated with 30% or less raw propolis. The aqueous propolis extract showed lower antimicrobial activity compared to the alcoholic extracts, indicating that ethanol is a better solvent for extracting the active compounds from propolis. It was observed that the MIC (0.06 to 0.2 mg/mL) and MBC (0.2 to 0.5 mg/mL) values for Gram-negative bacteria were higher compared to Gram-positive bacteria (MIC 0.001-0.2 mg/mL, and the MBC 0.02-0.5 mg/mL). The propolis extracts that exhibited the highest antimicrobial activities were from stingless bees hebora from the Distrito Federal (DF) and mandaçaia from Santa Catarina, showing comparable efficacy to samples 5, 6, and 7, which were the green propolis from the DF. Hence, these products can be considered an excellent source of bioactive compounds with the potential for utilization in both the pharmaceutical and food industries.

Salmonella represents one of the most common foodborne pathogens, frequently associated with the contamination of poultry products, constituting a prominent worldwide public health concern. This study determined the prevalence and antimicrobial resistance of Salmonella spp. in chilled chicken meat (115 samples) commercialized at retail in the Federal District, Brazil. Microbiological tests were performed to screen for Salmonella spp. in the chicken meat samples, and the isolated strains were confirmed by the invA gene presence (PCR technique). The strains were evaluated for antimicrobial susceptibility by the disk diffusion technique (Kirby-Bauer method) and tested for the presence of the sul2, blaCTX, and tetB antimicrobial resistance genes. The Salmonella spp. prevalence in chilled chicken meat sold at retail in the Federal District, Brazil, was 46.1% (53 of 115 chicken meat samples analyzed had invA gene-positive strains). Seventy-eight strains of Salmonella spp. isolated from the 53 contaminated samples showed higher resistance to amoxicillin/clavulanic acid (83.3%), followed by sulfonamide (64.1%) and tetracycline (46.2%); 53.8% of the isolates were multidrug-resistant (MDR). The sul2 gene that confers resistance to sulfonamide was found in 53 strains (68.0%), the blaCTX gene that confers resistance to beta-lactams was identified in 39 strains (50.0%), and the tetB gene that confers resistance to tetracycline was identified in 29 strains (37.2%). The high percentage of Salmonella contamination in chicken meat can pose a risk to consumers’ health due to the possibility of causing salmonellosis. In addition, many isolates were MDR and carried antimicrobial resistance genes. Public agencies can use these results to develop effective public health policies and strategies to ensure the safety of these food products.

Resumo O sushi é um alimento pronto para consumo composto de arroz acidificado com vinagre e recheio de peixes crus e vegetais. O ácido acético do vinagre diminui o pH do arroz e auxilia na conservação do sushi por retardar o crescimento microbiano. O objetivo deste estudo foi avaliar o efeito antibacteriano do vinagre de arroz mediante determinação da sua concentração inibitória mínima (CIM) e concentração bactericida mínima (CBM) e determinar a qualidade microbiológica de sushis comercializados na cidade de Brasília, Distrito Federal. Para as análises microbiológicas, dez amostras de sushi foram coletadas em restaurantes especializados em culinária oriental e dez amostras de sushi foram coletadas em locais não especializados em culinária oriental, como supermercados e padarias, totalizando 20 amostras. As análises realizadas foram contagem total de bactérias mesófilas e psicrotróficas, determinação de coliformes totais e coliformes termotolerantes, contagem de Staphylococcus aureus, pesquisa de Salmonella spp. e identificação molecular de S. aureus por PCR. O vinagre de arroz teve efeito antibacteriano tanto para as bactérias Gram-positivas (S. aureus e B. cereus) quanto para as bactérias Gram-negativas (S. enterica e E. coli) testadas neste estudo. Os valores de CBM variaram de 3 a 50 mg de ácido acético/mL e os valores de CIM variaram de 2,5 a 3,5 mg de ácido acético/ mL. A maioria das amostras de sushi avaliadas neste estudo (80%) estava em condições microbiológicas aceitáveis para o consumo, de acordo com a legislação brasileira. No entanto, quatro amostras (20%) excederam o limite aceitável para S. aureus, portanto estavam impróprias para consumo. Essas amostras impróprias para consumo eram provenientes dos restaurantes especializados em culinária oriental. A presença elevada de bactérias S. aureus nessas amostras de sushi indica condições higiênicas inapropriadas, por se tratar de uma bactéria procedente de manipulação humana inadequada.