The bubble for online grocery sales in the US appears to be deflating, according to recent data from insight firm Brick Meets Click.

The firm found total US online grocery sales in May were down 16 percent to $7 billion (€5.9 billion) versus a year ago. That stands in stark contrast to March, when sales were at $9.3 billion (€7.8 billion), a 43 percent increase over a year ago.

"Once people get a chance to go back to the store, they are going back to the store," Michael Swanson, chief agricultural economist at US financial giant Wells Fargo, told IntraFish.