Effect of culture media on Lactobacillus hydrophobicity and electrophoretic mobility

Dairy products are suitable vehicles for delivering beneficial microorganisms to consumers. Both Lactobacillus reuteri RC-14 and Lactobacillus rhamnosus GR-1 are considered as probiotic agents with therapeutic properties. The objective of this study was to monitor growth and survival of these bacteria in milk during storage period. Four formulations of milk (1 % fat) with 0.33% yeast extract (Y), 0.4% inulin (I), 0.33% yeast extract and 0.4% inulin (YI) and one with no additives (N) were prepared. The mixtures were autoclaved for 15 min, cooled to 37 °C and inoculated with 1 % of starter culture. They were then incubated anaerobically at 37 °C overnight. Viable numbers of L. reuteri RC-14 and L. rhamnosus GR-1 were determined after 1, 7, 14, 21 and 28 days of storage at 4 °C. Both bacteria were able to grow and survive in all samples; however, they showed a higher survival rate (P \u3c 0.05) in YI treatment. After 1 day of storage, the total colony counts of treatment YI for L. reuteri RC-14 and L. rhamnosus GR-1 were 2 × 10 and 1 × 10 CFU mL , respectively. The total colony counts for treatment YI decreased by 1 log cycle for both bacteria after 28 days of storage. The results of this study indicate that these bacteria can remain viable over the storage period, and there is potential for incorporating them into fermented dairy products. © 2007 Institute of Food Science and Technology Trust Fund. 8 9 -

Redução da força de retenção e abertura de grampos a barra em "I" de Roach e sua correlação Retention drop and opening of I-bar partial denture clasps, and their correlation

A pesquisa utilizando grampos a barra em "I" de Roach teve por objetivo determinar a diminuição da força de retenção após 20 mil ciclos de inserção e remoção. Também determinou-se a abertura dos grampos durante a ciclagem e a correlação com a diminuição da retenção. Usaram-se 2 ligas à base de Co-Cr (Vera PDI e Wironit) e 4 tipos de grampos (CF, curto-fino; CG, curto-grosso; LF, longo-fino; LG, longo-grosso). Ainda os corpos-de-prova foram cobertos ou não, parcialmente, com resina acrílica. Os resultados permitiram concluir que: as ligas apresentaram diminuição de retenção semelhantes; as aberturas dos grampos foram semelhantes nos diversos tipos de grampos, mas a perda de retenção menor foi para o longo-fino e maior para o curto-grosso; a cobertura parcial dos grampos com resina não influiu em sua abertura mas aumentou significantemente a perda de retenção; não foi encontrada correlação significante entre abertura e diminuição de retenção dos grampos.<br>The purpose of this research was to determine the retention drop of I-bar clasps, their possible opening during mechanical cycling and their correlation. Two Co-Cr alloys were used and the design of clasps were: short-thin; short-thick; long-thin; long-thick. Clasps were also partially covered or not with resin. Measurements were made at the initial stage and after 20 thousand cycles. The results led to the following conclusions: the alloys presented similar retention drop; opening of the several types of clasps were similar, but retention drop was minor on long-thin clasp and major on short-thick ones; resin did not influence the opening of clasps but increased retention drop; correlation between retention drop and opening of clasps was not significant