RESUMEN
This study evaluated the effects of incorporating the probiotics Bifidobacterium animalis subsp. lactis Bb-12 (B. lactis) or Lactobacillus acidophilus La-05 (L. acidophilus) into goat ricotta on the technological, physicochemical, physical and sensory parameters of this product during refrigerated storage, as well as the protective effects of the goat ricotta on the survival of the tested probiotics during exposure to simulated gastrointestinal conditions. Incorporating the tested probiotics did not affect the yield or syneresis of the obtained goat ricotta. The counts of L. acidophilus and B. lactis during the chosen storage period were approximately 6 log CFU/g. The ricotta samples containing a probiotic strain presented smaller and greater amounts of lactose and lactic acid, respectively, and exhibited greater hardness and lower brightness after storage compared with the samples lacking a probiotic. No differences were observed in the fatty acid profiles of the goat ricotta containing or not containing a probiotic. All of the ricotta samples were described as a soft cheese with a homogeneous texture; however, the goat ricotta cheeses containing L. acidophilus or B. lactis were described as having a more acidic flavor. At the end of a challenge using experimental human digestive conditions, the counts of each of the tested probiotic strains were approximately 6 log CFU/g if it had been incorporated into goat ricotta. These results demonstrated the feasibility of incorporating L. acidophilus or B. lactis into goat ricotta because these probiotics did not negatively affect the quality characteristics of this product and suggested that goat ricotta is an efficacious food matrix for maintaining the viability of these probiotics during storage and under the stressful conditions imposed by the human gastrointestinal tract.
RESUMEN
This study assessed the capacity of adhesion, the detachment kinetic and the biofilm formation by Staphylococcus aureus isolated from food services on stainless steel and polypropylene surfaces (2 × 2 cm) when cultivated in a meat-based broth at 28 and 7 °C. It was also to study the efficacy of the sanitizers sodium hypochlorite (250 mg/L) and peracetic acid (30 mg/L) in inactivating the bacterial cells in the preformed biofilm. S. aureus strains adhered in high numbers regardless the assayed surface kind and incubation temperature over 72 h. Cells detachment of surfaces revealed high persistence over the incubation period. Number of cells needed for biofilm formation was noted at all experimental systems already after 3 days. Peracetic acid and sodium hypochlorite were not efficient in completely removing the cells of S. aureus adhered on polypropylene and stainless steel surfaces. From these results, the assayed strains revealed high capacity to adhere and form biofilm on polypropylene and stainless steel surfaces under different growth conditions. Moreover, the cells in biofilm matrix were resistant for total removal when submitted to the exposure to sanitizers.
Asunto(s)
Biopelículas/crecimiento & desarrollo , Desinfectantes/farmacología , Microbiología Ambiental , Manipulación de Alimentos , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/fisiología , Adhesión Bacteriana , Pruebas de Sensibilidad Microbiana , Ácido Peracético/farmacología , Hipoclorito de Sodio/farmacología , Staphylococcus aureus/aislamiento & purificación , Temperatura , Factores de TiempoRESUMEN
This study assessed the capacity of adhesion, the detachment kinetic and the biofilm formation by Staphylococcus aureus isolated from food services on stainless steel and polypropylene surfaces (2 x 2 cm) when cultivated in a meat-based broth at 28 and 7 ºC. It was also to study the efficacy of the sanitizers sodium hypochlorite (250 mg/L) and peracetic acid (30 mg/L) in inactivating the bacterial cells in the preformed biofilm. S. aureus strains adhered in high numbers regardless the assayed surface kind and incubation temperature over 72 h. Cells detachment of surfaces revealed high persistence over the incubation period. Number of cells needed for biofilm formation was noted at all experimental systems already after 3 days. Peracetic acid and sodium hypochlorite were not efficient in completely removing the cells of S. aureus adhered on polypropylene and stainless steel surfaces. From these results, the assayed strains revealed high capacity to adhere and form biofilm on polypropylene and stainless steel surfaces under different growth conditions. Moreover, the cells in biofilm matrix were resistant for total removal when submitted to the exposure to sanitizers.