Israel’s Health Ministry and the Weizmann Institute of Science will conduct random sample coronavirus tests in supermarkets to determine where the virus is spreading.

The tests had been scheduled to start Monday in branches of three major supermarket chains, but were delayed after the locations of the tests leaked to the public. That raised fears of people with COVID-19 symptoms rushing to the supermarkets in order to get a test, potentially infecting others, the Israeli business daily Globes reported.

The ministry had coordinated the visits with supermarket managers but now will not provide advance warning.

The random samples will be taken from shoppers and cashiers, according to the report.

While most businesses in Israel have been shuttered due to directives from the Health Ministry, supermarkets remain open since they are considered an essential service.