Hong Kong custom officials arrested 45 people trying to smuggle baby milk formula across the border into mainland China.

Among those detained for carrying more than permitted amount of baby milk formula were 26 Hong Kong residents and 18 people from the mainland. One person had a foreign passport and some of the alleged smugglers were cross-border drivers, officials said.

A total of 115 cans of milk powder believed to be worth about $4,500 were seized by authorities on Friday and Saturday, Hong Kong’s Secretary for Security Lai Tung-Kwok said.

Hong Kong implemented strict measures to tackle shortages of baby milk formula caused by food-safety-conscious mainland Chinese hoarding the product across the border, usually by train.

People carrying more than 1.8kg of infant formula into China are subject to a maximum penalty of two years in jail and a fine of 500,000 Hong Kong dollars ($64,500).

Lai said the government anticipated that traders may change their tactics to get the product out of Hong Kong, with a move towards using cars for cross-border trips and in some cases ships to take the product to Vietnam and from there to China, reports Financial Times.

Chen Zhu, China’s health minister, expressed “deep concern” over the increasing reports of baby milk smuggling to the mainland but said it is only a “temporary problem”.

“The milk powder problem is something we don’t need a long time to solve,” Chen said Monday.

Mothers from mainland China have been opting to buy baby milk in Hong Kong after a scandal revealing that Chinese companies were found to be mixing melamine into baby formula. More than 300,000 infants suffered kidney problems and six died after consuming the formula in 2012, according to Financial Times.

Beijing is considering creating a food and drug safety agency to deal with increasing concerns about food safety in mainland China, reports South China Morning Post.