Google says it is ramping up enforcement of its new unique product identifier feed specification for Google Shopping. Google announced the changes in May.

In case you missed it, Google said it was improving support for merchant-defined multipacks. The feed specification now clarifies how multipack products should be submitted. As it moves toward high-resolution displays, Google also started recommending higher-quality images with at least 800 pixels in height and width.

For products like custom goods, vintage items, collectibles, etc., which don’t have unique product identifiers, Google introduced the “identifier exists’ attribute, and updated its requirements on unique product indentifiers.

Google also updated its guidance for the description and color attributes to make them “more precise and actionable,” and started providing dedicated support for energy efficient labels and unit pricing for merchants targeting countries in the European Union and Switzerland.

Additionally, Google launched the ability for merchants promoting non-family safe items on family-safe websites to tag individual items as such.

When Google announced all of these changes, it said that for accounts that were exempted from requiring unique product identifiers, it would start enforcing the new requirements on July 15th in the U.S., and on September 16th elsewhere. For all other accounts, enforcement would start on July 15th in the U.S., France, Germany, and the U.K., and September 16th for everywhere else.

Non-compliant items face disapproval, and will disappear from Google Shopping, Google said.

Google now says enforcement of the new specs has begun, and will continue to ramp up over the coming weeks, and that by September, all violating offers will be rejected, and will not be served through product listing ads.

“These new feed specifications will affect all accounts in the United States and non-exempt accounts in France, Germany, and the United Kingdom,” says Google Shopping program manager Angelika Rohrer. “Beginning September 16th, all previously exempt accounts in France, Germany, and the United Kingdom as well as all other targeted countries will be subject to these new requirements.”

Google has pages for unique product identifier requirements and product feed specifications here and here respectively.

On Friday at 12PM Eastern, Google will host a Hangout to help merchants with the changes and answer questions about feeds.