"At home we eat a lot of raw vegetables," Lucka tells news agency AFP, speaking of the most likely cause mentioned by German authorities for the outbreak.
"But both my husband and I are fit and well," adds this nurse who still cannot understand how her boys, Johannes, 12, and Maximilian, 14, could have fallen ill to the virulent E.coli bacteria which has so far killed 16 in Germany and one in Sweden.
"It all started with bad tummies, and then came diarrhoea. But you don't just run to the doctor because of such things," she says. But the boys quickly got worse.
On May 22, they were rushed to the Eppendorf University Clinic where Johannes was immediately operated on and placed him on dialysis because of failing kidneys.
Contamination at its worst develops into a full-blown disease - known as haemolytic uraemic syndrome (HUS) - with bloody diarrhoea, kidney failure and
In Hamburg, the city most affected by the outbreak, officials on Wednesday put the figure of confirmed and suspected bacteria cases at 668, with 124 of these HUS.
Maximilian has since returned home, but Johannes remains in hospital - one of 20 children struck by the disease which has felled mainly women. Some 60 adult patients are also hospitalised here.
"I'm slowly starting to eat again, the worst is over," says Johannes, looking pale lying in his hospital bed.
The clinic's first floor, reserved for emergency treatment, is closed to the public, with only the relatives of those ill allowed in.
At the front door, a notice urges visitors to donate blood as many patients require plasma treatment.
"I know how important it is for a hospital to have enough blood, especially now when the need is so great because of the bacteria," says Jürgen Hentschel, a 61-year-old retired policeman who turned up to give blood.
In Hamburg and the neighbouring region of Schleswig-Holstein, also badly hit by the contamination, the Red Cross is running short of blood.
"We've delivered 7,000 bags of plasma over the past week. Normally we deliver 800 a month," says regional Red Cross spokesman Jens Lichte.
"A victim of this bacteria needs daily blood transfusions from 10 to 15 donors," he added.
Hamburg health officials say they have so far been able to cope, but the situation, they add, is deeply worrying.