Hershey has determined that a soy ingredient used in chocolate making was the source of contamination that prompted a recall of two dozen products.

A variety of popular chocolate bars and candies were voluntarily recalled on Nov. 9 because of fears of salmonella contamination at its Smiths Falls, Ont., factory.

Hershey now says soy lecithin was the contaminant, but would not confirm if the soy was contaminated with salmonella.

Soy lecithin is used to help chocolate flow more easily during manufacturing.

The company said that according to the supplier, this ingredient was shipped exclusively to the Smiths Falls plant, though Hershey has not revealed the supplier's identity.

The company, which employs 500 workers in the eastern Ontario town, shut down production and issued a recall of 25 products after a routine inspection inside the plant detected salmonella on Nov. 9.

The Canadian Food Inspection Agency said the plant will remain closed until an investigation has been completed.

Most of the recalled candy is believed to have been contained at distribution and warehouse centres and was not sent to retailers, according to the CFIA.

The products involved in the recall can be identified by date codes — ranging from 6417 to 6455 — found on the back of each package.

The other recalled products are:

• Hershey Chipits Milk Chocolate Chips, 270 g.
• Hershey Creamy Milk Chocolate With Almonds, 43 g.
• Hershey Creamy Milk Chocolate, 45 g.
• Oh Henry! 62.5 g; 62.5g/4 bars, 145 g.
• Oh Henry! Bites, 130 g.
• Oh Henry! Peanut Butter, 60 g.
• Hershey Chipits Semi-Sweet Chocolate Chips, 350 grams, 2 kg.
• Hershey Chipits Semi-Sweet Mint Chocolate Chips, 300 g.
• Hershey Semi-Sweet Chocolate Chips, 300 g.
• Hershey's Special Dark Chocolate, 45 g.
• Hershey's Special Dark Chocolate with Almonds, 43 g.
• Reese's Peanut Butter Cups, 51 g, 68 g, 51 g/4 bars.
• Lowney Cherry Blossom, 45 g.
• Glosette Peanuts, 45 g.
• Glosette Almond, 42 g.
• Glosette Raisin, 50 g; 145 g.
• Hershey's Chocolate Shell Topping, 177 ml.
• Eat-More Dark Toffee Peanut Chew, 56 g; 56 g/4 bars.
• Lowney Bridge Mix, 52 g; 340 g.
• Hershey Assorted 16 count, 728 g.
• Hershey Assorted 50 count, 2.5 kg.
• Hershey Chipits Mini Chocolate Chips, 300 g, 10 kg (bulk), 175 g, 500 g.
• Hershey Chipits Chocolate Chip Bulk, 10 kg (bulk).
• Nut Roll, 5 kg (bulk).
• Hershey Semi-Sweet Chocolate Chips, 10 kg (bulk).
• Chocolate-coated almonds sold between Oct. 23 and Nov. 10 at the Hershey Chocolate Shoppe at the factory.

No products produced for Halloween or Christmas are affected, the company said.

Foods tainted with salmonella may not look or smell spoiled, but the bacteria can cause symptoms such as high fever, severe headache, vomiting, nausea, abdominal pain and diarrhea. People with weak immune systems are particularly vulnerable to salmonella poisoning.

There have been no reported illnesses associated with the consumption of the Hershey products.