TAIPEI (CNA) -- Taiwan has begun checking all passengers arriving in the country from Vietnam for possession of pork products after a pork sandwich brought into Taiwan by a traveler from Ho Chi Minh City tested positive for African swine fever (ASF).



It was the latest step taken by Taiwan to keep the ASF virus out of the country after a widespread outbreak in China.



The government has already imposed 100 percent checks of carry-on bags of passengers arriving from China and raised fines for having undeclared pork products to NT$200,000 (US$6,486) for first time offenders and NT$1 million for multiple offenders.



Authorities fear the spread of ASF, which is deadly to pigs, could destroy Taiwan's pig-farming industry, which contributes more than NT$100 billion (US$3.24 billion) a year to the domestic economy.



The pork that tested positive for ASF was discovered in a random check of a Taiwanese passenger at Tainan Airport after the individual arrived from Ho Chi Minh City on Feb. 5, the Council of Agriculture (COA) said.



The passenger was only fined NT$30,000 rather than NT$200,000, however, because Vietnam is classified as being affected by foot-and-mouth disease but not ASF.



Laboratory testing confirmed on Friday the presence of ASF in the sandwich, the COA said.



It was the first time a pork product brought into Taiwan from a country other than China has tested positive for the virus, triggering the tightening of the government's pork restrictions.



"Beginning from 6 p.m. Friday, Taiwan has implemented a 100 percent check of hand luggage carried by passengers arriving from Vietnam, and the measure will be in place until we can confirm that there is no ASF outbreak in Vietnam," COA chief Chen Chi-chung (陳吉仲) said at a press conference Friday.



Chen said Taiwan has informed the Vietnamese government and the World Organisation for Animal Health (OIE) of the ASF-confirmed case.



Authorities suspect the pork sample may actually have originated from China, however, because it contained genetic sequences identical to those of the swine fever virus strain found in China.



Passengers who arrived at Taiwan Taoyuan International Airport on VietJet Air 942 from Hanoi at 6 p.m. became the first group of passengers to have their carry-on bags fully checked.



But while stricter inspections have been imposed, the penalties for bringing in meat products from Vietnam will not be increased since it is not classified as an ASF-infected area, said Feng Hai-tung (馮海東), head of the Bureau of Animal and Plant Health Inspection and Quarantine.



Under existing rules, passengers found with meat products from countries and areas with foot and mouth disease or highly pathogenic avian influenza are fined NT$30,000 for a first offense, NT$300,000 for a second offense and NT$1 million for multiple offenses.



Meanwhile, two more pork products brought into Taiwan from China tested positive for the virus on Friday, bringing the total number of ASF-confirmed cases from China to 22, the Emergency Operation Center for African swine fever said.



Since the number of meat products illegally brought into Taiwan from Vietnam ranks only second to those from China, customs officials have been collecting samples of Vietnamese pork products obtained in random checks of passengers since November last year.



As of Feb. 13, 54 such products had been tested but none were found to have the ASF virus, the COA said.