The link between Nestlé’s Toll House refrigerated cookie dough and an E. coli outbreak in the US demonstrates the need for more frequent and better food safety testing methods, a leading food safety expert has suggested.

Nestlé USA voluntarily recalled about 300,000 cases of refrigerated Toll House cookie dough products due to a link between the product and an outbreak of illnesses caused by E. coli in more than 25 states.

“The mystery of this situation is how this strain of bacterium, which normally lives in animals like cattle, deer and sheep, is connected with a product like cookie dough,” said Purdue University’s Bruce Applegate.

“Factors like plant equipment, factory workers’ health and hygiene, water sources, bulk ingredients, and packaging material must be examined to determine the source of the outbreak. The unusual circumstance of the Nestlé recall suggests the need for increased routine testing of the nation’s food supply before products are sent to market.”