The structure of six Irish kefir samples was studied in the electron microscope, and the microbial composition and fermentation kinetics during growth in 10% reconstituted skim milk at 21°C. The microbial composition of the six samples was similar; at the end of the fermentation the counts of lactococci, leuconostocs, lactobacilli, acetic acid bacteria and yeasts were 109, 108, 5 × 106, 105 and 106 ml−1 respectively; the levels of acetic acid bacteria and lactobacilli showed some intersample differences. Lactate was the major metabolite followed in order by ethanol, acetate and acetoin. The final concentrations of L‐lactate produced (66–90 mmol kg−1) were 10‐fold higher than those of D‐lactate. Acetate and ethanol concentrations varied from 4 to 14 and 2 to 40 mmol kg−‘1 respectively. The rates of citrate utilization and concentration of acetoin produced during growth differed between samples. Scanning electron microscopy showed not only variation between the interior and exterior of the sample but also large variation between different sections of the interiors and exteriors of the same sample. Long and short, and straight and curved rods and yeasts were seen in all samples, the curved rods observed in the interior, but lactococci were seen on the surface of only one sample. There were no gross differences in structure between samples.

The effect of a controlled lactic fermentation on textural and ultrastructural properties of salmon ®llets was evaluated. When compared with a non-inoculated cured sample, fermented salmon had unique textural properties since it exhibited signi®cantly higher force (p`0.05) and work (p`0.001) values in a penetration test on two sampling days but a consistently lower hardness (p`0.05) in a Texture Pro®le Analysis (TPA) rheological test. Study of the myo®brillar ultrastructure showed that basic structures were drastically damaged during processing and storage of fermented and cured salmon. Nevertheless, Z-lines were better preserved in fermented samples. It is suggested that the slight protective effect of lactic fermentation with the starter L sake may be the consequence of a lower pH, by putatively inhibiting neutral or alkaline proteolytic enzymes.

No abstract

The articular tissue generated on carbon fiber rods in rabbit knee joints after 75 days of intermittent active motion was compared with tissue generated on carbon fiber rods whose articular surfaces were covered with a free reversed periosteal graft. Both methods were effective in generating articular tissue; however, tissue with ultrastructural characteristics similar to those of hyaline cartilage was noted more frequently on the composite implants. If such composite implants were clinically effective then they might be useful in treating symptomatic osteochondral defects.

No abstract