[OS X TeX] Beamer, columns within itemize

[Oliver Buerschaper]

Dear folks,

I'm preparing a presentation (due on Monday) with the beamer class and  
I'd like to have two columns for each item in an itemize environment.  
I've tried

---
\documentclass{beamer}


\begin{document}


\begin{frame}
     \frametitle{Title}
     \begin{itemize}
         \item Fruit
             %\rule{\linewidth}{.4pt}
             \begin{columns}[totalwidth=\linewidth,t]
                 \begin{column}{.5\linewidth}
                     Enter text into the left column
                 \end{column}
                 \begin{column}{.5\linewidth}
                     Enter text into the right column
                 \end{column}
             \end{columns}
         \item Vegetable
     \end{itemize}
\end{frame}


\end{document}
---

Unfortunately, while the rule (if uncommented) recognizes the current  
(local) linewidth of the item and is correctly left aligned with  
"Fruit" the columns environment isn't. Does someone know how to fix  
this?

Many thanks for your help,
Oliver