SHANGHAI - The Coca-Cola products that tested positive for a banned preservative in Taiwan have been recalled, and the Coca-Cola Co said its products on the Chinese mainland are completely safe to drink.

Recent media reports that a batch of Coke Zero concentrate from Shanghai contained the banned preservative methyl-p-hydroxybenzoate sparked concern about the safety of beverages.

The batch of Coke Zero concentrate was made by Coca-Cola's Shanghai company. Media reports said the chemical may lead to inflammatory lesions of the skin and mucous membranes, and raise female hormone levels.

Coca-Cola Co said the preservative has been used in many areas including the Chinese mainland, Hong Kong and the United States.

"This ingredient is widely used as an acceptable and safe additive in food and drink, but Taiwan's laws and regulations do not permit its use in sparkling beverages," the company told China Daily on Monday.

"Coca-Cola maintains high-quality standards and our products are safe for consumption on the Chinese mainland," Zhai Mei, a public relations director of Coca-Cola, told China Daily.

"The sample tested by Taiwan authorities was Coke Zero concentrate, and the percentage of the preservative would be much lower when diluted," she added.

Reports said 2.062 grams of the preservative was detected per kilogram in the Coke Zero concentrate in Taiwan.

The level of methyl-p-hydroxybenzoate in Coke Zero after final dilution is only 0.015 mg/kg, much lower than the national standard of about 200 mg/kg, according to the company.

The preservative is mainly used in the concentrate of Coke Zero for "post-mix" drinks that are often sold in fast food restaurants like McDonald's. Coke Zero packaged products, including cans and plastic bottles, do not contain the preservative, Zhai said.

McDonald's couldn't be reached for comment on Monday.

Coca-Cola Taiwan Co said the batch of Coke Zero concentrate was transported to Taiwan by mistake, and its products made in Taiwan do not have the preservative, Beijing News reported on Monday.

Meanwhile, two other kinds of preservatives, benzoic acid and hexadienic acid, were also detected in excessive amounts in the sample of Coke products. These chemicals may cause irritation to skin and eyes.

Despite the declaration by Coca-Cola, consumers are still worried about food safety issues.

"This is another alarm following a series of food safety scandals across the country. Taiwan bans this preservative but the mainland doesn't. Why does the mainland have a comparatively more lax standard than Taiwan? I think the mainland should establish the same standard as other areas," said a local resident surnamed Yang.

The Ministry of Health said it has started an investigation on the preservative.

Hu Minghao contributed to this story.