Walmart and its unit Sam's Club said on Monday leafy greens suppliers will be asked to implement real-time, farm-to-store tracking using blockchain technology by next September, as the retailer tackles food-safety incidents.

Walmart is among several other retailers such as Nestle SA trying to tap blockchain, a shared record of data kept by a network of computers to track food supply chain and improve safety.

Last year, Nestle, Unilever Plc, Tyson Foods Inc and other large food and retail companies joined IBM's blockchain technology project.

Walmart said on Monday that the Centers for Disease Control and Prevention (CDC) has consulted with the company to improve traceability of food products to help public officials investigate and find the source of food-borne disease outbreaks.

The United States has seen several disease outbreaks in the past few years related to food products.

At least five people died and dozens were taken ill earlier this year due to an outbreak of E.coli linked to Romaine lettuce, the CDC said here in June.

First US death in romaine lettuce E.coli outbreak

In 2016, Walmart collaborated with IBM and Tsinghua University to track food products movement using blockchain technology in China.