Alpha hydrogen and hyperconjugation
To remember:

Hyperconjugation is the stabilising interaction that results from the interaction of the electrons in a σ-bond (usually C-H or C-C) with an adjacent empty or partially filled p-orbital or a π-orbital to give an extended molecular orbital that increases the stability of the system. Further information.

The proposed systems to take into account.

Looking at the resonance structures (which is a synonym of mesomeric effect) of the propene


(source: tutorvista.com)  

and acetic acid


(source: nonsibihighschool.org)  

Therefore, in hyperconjugation analysis you need to look at the position of the electron density. Not the vicinal hydrogen. 

Moreover and with the aim to give a complete answer, the hyperconjugation of the acetic acid can be very well understood at here.