Hawking food and cooking in the open have been banned by the county government as part of measures to manage the cholera scare.
The county administration has also said it will unveil new guidelines on catering services in the city to tighten the loose ends on hoteliers' operations.
County Health Executive Bernard Muia directed that no catering service providers would be allowed to offer services at any event of any class without a public health officer giving them the green light.
The directive follows an outbreak of suspected cholera at a conference organised last week by the Ministry of Trade at the Kenyatta International Convention Centre (KICC).
Six cases were reported, among them Industrialisation Cabinet Secretary Adan Mohamed and Treasury's Henry Rotich, who have threatened to take legal action against the conference organisers who outsourced catering services from San Valencia Restaurant.
Already, samples, among them environmental, food and stool swabs from the food handlers have been taken for culture and sensitivity testing at the National Public Health Laboratories.
However, the county health boss maintained that it had not been conclusively confirmed that the six delegates did actually have cholera despite the preliminary rapid tests showing the presence of cholera-causing bacteria.
"We are expecting culture results by Wednesday (this week)," said Dr Muia.
Speaking to The Standard, the Kenya Association of Hotel Keepers and Caterers have insisted they are not to blame for the cholera scare as the national government has remained cagey about the spread of the disease and its actual impact.
The association argued that the city county government could not conclusively point out the root cause of the disease.
Mike Macharia, the KAHC boss, said the move by the county administration to impose new directives was simply a 'knee jerk' reaction that was not proportionate to the actual scare facing Kenyans.
"The underlying question is; have they established the root cause of the spread? They need scientific proof and this starts with isolating the cases," said Mr Macharia.
He said it was unnecessary for the county government to come up with another set of regulations on catering services when public health officials visit catering premises monthly for inspection.
Muia however said the new directives would only apply to those businesses that were not licensed.