Didier Gaspard Owen Maximilien, 19, was handed a SG$600 (€406) fine after admitting to posting to social media a video of himself putting a straw he had licked back into the dispenser of an orange juice vending machine.
Maximilien, who is studying in Singapore, posted a video of himself executing the prank on Instagram with the caption "city is not safe".
The clip went viral on Instagram shortly after the incident on March 12, triggering a backlash that led to his arrest in Singapore, which is known for its strict enforcement of public order and hygiene rules.
Handing down the sentence, Judge Kelly Ho said given Maximilien's "age and nature of the offence", alternatives such as probation or a community-based sentence would not be imposed.
Prosecutors agreed to the defence's proposal for a fine, saying the offence was at the "lower end" of its seriousness and while hygiene was compromised, no member of the public used the straw, so there "was no evidence of harm".
They added that Maximilien "pleaded guilty at the earliest possible opportunity."
In Singapore, public nuisance offenders face up to SG$2000 (€1353) fine and three months in jail.
"He is fully sorry for having caused all this trouble," Maximilien's defence counsel Kalidass Murugaiyan told the judge.
iJooz vending machines are a common sight in shopping districts, selling freshly-squeezed orange juice for SG$2 (€1.35) a cup. The company said it replaced all 500 straws in the machine dispenser after the teenager's prank.
Singapore is known for its no-nonsense approach to public stunts.
Last year it deported an Australian man at the end of a nine-day jail term for rushing film star Ariana Grande during the Asian premiere of "Wicked: For Good".
