Ross made the argument during a CNBC appearance , shortly after the administration had announced it would slap a 25 percent levy on steel imports and 10 percent tariff on aluminum. Responding to fears that the duties would be inflationary, Ross said they actually would have little effect on prices, even in a worst-case scenario.

In an earnings call Friday, a Campbell official held up the tariffs as a negative factor in the company's future profitability.

In March, Commerce Secretary Wilbur Ross held up a can of Campbell's Soup to demonstrate how benign the effects would be of steel and aluminum tariffs.

"What I'd like to do, though, is to emphasize again the limited impact," he began. "This is a can of Campbell's Soup. In the can of Campbell's Soup, there's about 2.6 cents, 2.6 pennies, worth of steel. So if that goes up by 25 percent, that's about six-tenths of 1 cent on the price of a can of Campbell's Soup.

"Well, I just bought this can today at a 7-Eleven down here, and the price was $1.99. So who in the world is going be bothered by six-tenths of a cent?"

It turns out the company is being bothered by it plenty.

Campbell said it now expects profits to decline by 5 percent to 6 percent this year, worse than earlier projections of between 1 percent and 3 percent.

In addition, CEO Denise Morrison stepped down as the company announced a strategic review to try to reverse the sales slump.

Chief Financial Officer Anthony DiSilvestro pointed directly to the tariffs as a cause of the company's expected woes going forward. The tariffs did not actually take effect until March 23, near the end of the quarter.

"At this stage, given what we know about accelerating cost inflation in part due to the anticipated impact of import tariffs and the continuing headwind on transportation and logistics cost, we expect our margins will be down in fiscal 2019," he said.

Later, when facing tough questioning from an analyst on why the company's "tone is so negative" on its outlook, DiSilvestro responded that he was just "trying to be transparent" about the obstacles Campbell faces.

Again, he cited tariffs as a major factor in a broader scenario of rising costs.

"The issue is primarily one of cost inflation and we're seeing and expecting an acceleration on the rate of inflation across a number of ingredient and packaging items," DiSilvestro said. "For example, we expect double-digit increases on steel and aluminum. A lot of that [is] driven or all of it's driven by the impact of anticipated tariffs."

Shares plunged 12 percent on the comapany's forecast and the posting of a $393 million loss and were down more than 28 percent for the year as of afternoon trading.

Ross told CNBC on Friday that Campbell may be overstating the effect of the tariffs.

"It is physically impossible that a few days of a tariff resulted in a $393 million loss. They are using [the tariffs] as a cover-up for other problems," he said.

But a company spokesperson reiterated to CNBC that the comments about tariffs related to forward-looking results and not the loss for last quarter. CNBC followed up with Ross to see if he wanted to amend his statement, but had not yet heard back.

— With reporting by CNBC's Lori Ann LaRocco