SummaryWe performed in vitro, animal, and human studies to clarify the effect of mayonnaise on ␤ -carotene intake and its mechanism. In an artificial gastric juice model, we examined the transfer of ␤ -carotene from grated carrot to mayonnaise or vegetable oil. Mayonnaise was more easily dispersed in artificial gastric juice than vegetable oil. The ␤ -carotene concentration was greater in mayonnaise than vegetable oil. In rats, the postprandial serum ␤ -carotene concentration in the mayonnaise group ( ␤ -carotene with mayonnaise) was higher than that in the control ( ␤ -carotene only) and vegetable oil ( ␤ -carotene with vegetable oil) groups. Continuous feeding of dietary ␤ -carotene (14 d), employing mayonnaise or egg yolk, resulted in an increased accumulation of ␤ -carotene in the liver. In a human study, diets were provided in the form of (1) carrot as a control (CON), (2) carrot juice (JU), (3) carrot with oil (OIL) and (4) carrot with mayonnaise (MS). Following collection of fasting blood samples, nine adult males consumed one of the four diets in random order. Fasting and postprandial changes in serum ␤ -carotene were assessed at 2, 3, 4, 6 and 8 h following ingestion of each diet. The incremental areas under the curves of serum ␤ -carotene concentration were higher following MS than following both CON and JU. In conclusion, we suggest that mayonnaise contributes to raising the serum ␤ -carotene concentration when consumed with carrots rich in ␤ -carotene, and that its mechanism is related to the emulsifying property of the egg yolk contained in mayonnaise.

This study developed a method for extracting infectious prions from Class B biosolids and subsequently evaluated the survival of infectious prions under the influence of mesophilic (37°C) and thermophilic (60°C) temperatures in Class B biosolids. Unlike other studies, this study utilized a scrapie cell assay to determine infectivity and quantity of infectious prions. The best method for extraction was exposing the biosolids to 4 M urea at 80°C for 10 minutes followed by a membrane centrifugation to reduce the concentration of urea. The recovery efficiency of the infectious prions from the biosolids for this method was 17.2%. In the survival study, a 2.43-log(10) reduction in prion infectivity was observed under mesophilic temperatures after 15 days and a 3.41-log(10) reduction after 10 days under thermophilic conditions. The reduction of infectious prions was greater in the biosolids than the control in phosphate buffered saline, suggesting factors other than temperature were also playing a role in the loss of infectivity of the prions in the biosolids.

The objective of this study was to evaluate the fate of infectious prions in water. Known concentrations of infectious prions were added to deionized water, tap water, and wastewater. Samples were incubated at 25°C, 37°C, and 50°C for 1 to 8 weeks. The standard scrapie cell assay (SSCA) which includes the ELISPOT (Enzyme Linked Immuno-Spot) reaction was performed to determine prion infectivity and quantity as a function of time. A reduction of infectious prions was observed at 25°C, 37°C, and 50°C ranging between 0.5-log₁₀ and 1.4-log₁₀ in one week. Results suggest that organic matter was instrumental in protecting infectious prions, allowing them to remain infectious for a longer period of time. Thus, our data effectively show a quantifiable reduction of infectious prions in water and identifies some of the components that may influence infectivity.

No abstract

The ASTM Method D4994-89 has been used in the United States for almost two decades to assess the virological quality of biosolids. However, the efficiency of this method for recovery of different enteric viruses has never been determined. The method was found to recover several different enteroviruses and adenovirus 2 with an efficiency ranging from 18.1 ± 5.5 to 24.6 ± 7.8%.