Ziploc won a minor victory over competitor Hefty when Hefty's parent company was asked to modify claims for its food storage slider bags. Instead of claiming that the Hefty Slider seals are "2X stronger" than Ziploc's, Hefty can only claim that they are "stronger," according to a recommendation from the National Advertising Division, which mediates such disputes.
NAD noted in a press release that in developed product categories, "improving products becomes increasingly difficult as competitors close the performance gap between product lines. Product improvements, even when small, are beneficial to consumers and encourage positive competition in the marketplace."
To check the claims, the NAD reviewed shake, drop and stacking tests that were performed according to industry standards. The results showed that the Hefty seal "demonstrated superior strength to Ziploc under limited conditions" but could not be quantified as twice as strong. Reynolds, which makes Hefty bags, said it will accept NAD's suggestion "to slightly modify Reynolds' future advertising of its proven stronger seal than Ziploc and how it may benefit consumers."
While Ziploc, Hefty and Glad are duking it out for shelf space, some store brands are eating their lunch. Consumer Reports hasn't tested the new Hefty seal but in our last tests of food storage bags, Walmart's Great Value and Target's Up & Up bags were strong and convenient to close and cost considerably less. And most importantly, they didn't leak.
Hefty was a top pick in our recent tests of garbage bags (Ziploc didn't have an entry) as were two varieties of bags from Glad. But again, there were some store brands that were more economical and performed almost as well including Kirkland, Costco's house brand. Whatever bag you prefer, check unit prices. The number of bags per box varies widely and affects the cost per bag.
—Mary H.J. Farrell