\textit / \emph do not work in bfhbeamer

When using \textit in bfhbeamer, the text is not in italics.

Minimal example:

\documentclass{bfhbeamer}

\begin{document}
\begin{frame}
\textit{this should be in italics}

\textbf{this should be in bold}

\texttt{this should be in typewriter font}
\end{frame}
\end{document}

\textbf and \texttt work. \emph does not work either.