NHS Lanarkshire confirmed yesterday that health officials were investigating nine confirmed and nine suspected cases of the infection.
A spokesman said patients had either been discharged or were currently in Monklands Hospital. All were “well and responding to treatment”, he added.
Officials said initial investigations indicated a possible link to the JB Christie bakery in Airdrie.
Environmental health and public health staff are working with the bakery to carry out further investigations.
Hepatitis A is a viral infection which leads to inflammation of the liver and can cause mild to severe illness.
Officials said the infection “will clear with time and there are no long-term effects”.
Dr Josephine Pravinkumar, NHS Lanarkshire consultant in public health medicine, said: “Our initial investigations have indicated that there may be a link between these cases and the bakery.
“While the risk is very low, if anyone does experience a flu-like illness, loss of appetite, nausea, fever, abdominal pains or jaundice (a yellowing of the eyes or skin), they should contact NHS24 on 111 or their GP in the usual way.”
Dr Pravinkumar added: “We would like to thank everyone at the bakery for helping us with the investigation to identify any possible source.
“Once informed of the matter, the bakery owners took the decision to temporarily close their bakery and their two retail outlets in Airdrie and Coatbridge immediately and are fully cooperating with environmental health officers and public health staff.”
NHS Lanarkshire said the bakery owners had contacted outlets it supplies in North Lanarkshire as well as one in Cambuslang and one in West Lothian, asking them to withdraw their products from sale.
JB Christie managing director Andrew Chisholm said: “The health and safety of our customers and staff are of paramount importance.”