The final report on the salmonella outbreak that affected at least 32 residents in Muskegon and Ottawa counties last year, according to Michigan Live, lists no precise reason for the incident.

The 68-page document released by Public Health-Muskegon County this month formed nine hypotheses and suggested raw eggs, cross contamination or poor food handling were likely the cause of the outbreak that affected patrons and employees at Pints & Quarts Pub and Grill and C.F. Prime Chophouse and Wine Bar between Oct. 30 and Nov. 2.

Investigators said the restaurants’ salads — including those with grilled chicken — and Pints & Quarts’ Thai Chicken Lettuce Wraps appetizer were strongly associated with the illness.

The epidemiological investigation began on Nov. 8 and included a case-control study to determine the extent of the outbreak, the associated risk-factors and the necessary steps to control and prevent further infection.

The department interviewed 121 people. Nearly 60 people represented either confirmed cases or probable, unconfirmed cases and about 60 more represented the study’s “controls,” — those who dined out but did not get sick during the four-day exposure period.

The owners of the Roosevelt Park-based, Harris Hospitality-owned eateries said in a statement on Friday, Jan. 24 that they were “deeply disappointed” by the report’s findings.

Restaurant manager and owner Andy Harris said the company reviewed the document “in great detail” and characterized it as “repeatedly critical” of its policies and procedures leaving the reader with the impression that it did something wrong to make people sick.

Harris said management was frustrated the agency could not pinpoint a precise origin of the outbreak and said it should have concluded that raw eggs were to blame.

“We deeply regret that anyone was made ill eating at one of our restaurants,” Harris said. “However, the fault lies with the use of already-contaminated eggs and not with any of our food-handling practices or procedures.”

Restaurant spokeswoman Mary Ann Sabo said she did not know the name of the supplier.

The final report noted that raw eggs were used in the restaurants’ original Caesar and Citrus salad dressings and its béarnaise sauce, a classic French condiment made with butter and spices. Harris said the company has since modified the salad dressing recipes to exclude eggs.

The restaurants are allowed to use the raw eggs in condiments under the Michigan Modified Food Code of 2009 and its menus had noted the risks associated with consumption, he said.