A trainee chef at a leading public school recalled her surprise yesterday at seeing a kitchen aide allegedly try and poison the pupils' carrot and coriander soup.
Louise Samples, 21, was so shocked to see Maxwell Cook pouring a cleaning product into the soup at Stowe School in Buckinghamshire she did not immediately tell anyone else about it, she told Aylesbury Crown Court.
Mr Cook, 58, denies attempting to administer poison with intent to injure, aggrieve or annoy.
Miss Samples said she had seen him in the kitchen on 11 March last year pouring a product into the soup that is usually used to unblock drains.
"I was extremely shocked at what I saw and I carried on walking," she said. "I didn't feel comfortable enough to approach him."
She only told colleagues after hearing one of them commenting that the soup "didn't taste right", she added.
Mr Cook's barrister, Henry James, asked the trainee if she had poisoned the soup herself to discredit the main chef.
Miss Samples denied this, telling the court: "Everyone I work with is like a second family to me."
The soup was not eaten by any of the pupils at the £27,000-a-year school, as the cleaning product was detected during a standard tasting.
If ingested, it can cause irritation, vomiting and swelling of the throat.
Mr Cook, from Brackley, Northamptonshire, was suspended by the school after the incident.
The trial continues.