Realistically, even a good cold water wash will so greatly reduce the bacterial count by cavitation (e.g. mechanicl removal from the substrate) that only people with badly compromised immune systems would ever stand a change of getting infected. It's all about probability.
Realistically, you are wrong on many levels. Hepatitis A is not a bacteria, it a virus. There is a difference.
Secondly, many people have had Hepatitis A and are completely unaware. It doesn't matter the state of ones immune system.