How to register date / time a product was updated?

-- HikaShop version -- : 2.6.1
-- Joomla version -- : 3.4.8

There is a field product_created that I understand stores the time string when the product was created.

But can't see the same field for product_updated.

I would like to know how can I identify via a query or a mass action what products have been updated since a certain date/time.

And I need to avoid that the Hits Counter update is influencing the product update date as this is not a voluntary data update.