Police said they are also still investigating other lines of inquiry in the case, which may lead to additional arrests.
Israel Police arrested a man in his 40s from southern Israel on Monday in connection with the baby food sold in Jerusalem grocery stores, which was found to contain strong sedatives when tested earlier this year.
Police arrested the suspect at his home and took him for questioning, police added. He will be brought before the Jerusalem Magistrate's Court on Wednesday, where police will request an extension of his detention.
Police said they are also still investigating other lines of inquiry in the case, which may lead to additional arrests.
At the outset of the investigation in June, the Health Ministry confirmed that laboratory tests found clonazepam (sold under the brand names Klonopin or Klonex) and lorazepam in jars of Prinok baby fruit puree sold at two branches of Zol Begadol, a discount supermarket chain in Jerusalem.
The products were purchased at the chain's Mahaneh Yehuda branch at 113 Jaffa Street, and at another branch at 214 Jaffa Street, both in the center of the capital.
Clonazepam (sold under brand names Klonopin or Klonex) and lorazepam (sold under brand names Ativan or Lorivan) belong to the benzodiazepine family, a class of prescription drugs used as sedatives, anti-anxiety medications, and other treatments.
According to the Health Ministry, a total of five tainted products were found during the investigation, with three handed over by customers and two found on store shelves. All five showed signs of tampering prior to purchase.
Three small children, aged 3 years and under, were hospitalized in June after consuming the purees; doctors found traces of benzodiazepines in their blood and were ultimately able to discharge them from the hospital in stable condition.
KAN News reported that police actually opened an investigation into the matter in May after two other children were hospitalized after consuming Prinok baby food. The report claimed that the Health Ministry did not ask police to test a suspicious jar of the puree. Police added that they alerted the Health Ministry to the issue after the May incident and did not receive further instructions on how to handle the tainted product.
Tzvi Jasper and Goldie Katz contributed to this report.