Confectionery giant Cadbury has pleaded guilty to six charges under food and hygiene regulations.
The firm's Dairy Milk bars were removed from UK shelves
More than one million chocolate bars were recalled in the UK after salmonella was found in some products between January and March 2006.
The charges on Tuesday related to conditions at the company's Marlbrook site near Leominster in Herefordshire.
The case at Hereford Magistrates' Court was adjourned for sentencing at Crown Court in Birmingham on 13 July.
Last month, Cadbury said pleaded guilty at Birmingham Magistrates' Court to three offences under food and hygiene regulations in connection with a salmonella scare that led to the recall of the chocolate bars.
On Tuesday the company admitted charges relating to the state of a drainage pipe, a roof vent, the layout of the factory and drainage and disinfection equipment.
The company has said the bill for dealing with the contamination may reach £30m.
Birmingham City Council, which alleged the firm put "unsafe" chocolate on the market for a period in 2006, is responsible for enforcing health and safety laws at Cadbury's plant in Bournville.
In a statement Cadbury said the company did not "sufficiently review and update certain aspects of production to meet the changing requirements of best practice."
"We sincerely regret these lapses and are focused on ensuring that this can never happen again," the spokesman added.
A review of quality and health and safety procedures has since taken place.