Prosecutors have accused Ghislaine Maxwell of allowing her prison cell to become "dirty and smelly" by not cleaning it and regularly failing to flush her toilet.
In a lengthy letter to a judge they rejected allegations from Ms Maxwell's lawyers that her conditions were "fitting for Hannibal Lecter".
They also disputed suggestions the former socialite had lost 15 pounds, and some of her hair.
Watch: Federal prosecutors hit back at complaint by British socialite Ghislaine Maxwell has to be reminded to clean cell
A claim that she had been physically abused during a pat-down search had been investigated and was "unfounded", they added.
Audrey Strauss, a New York prosecutor, wrote: "Staff directed the defendant to clean her cell because it had become very dirty.
"Among other things, staff noted that the defendant frequently did not flush her toilet after using it, which caused the cell to smell. In addition, the defendant had not cleaned her cell in some time."
Ms Maxwell, 59, has pleaded not guilty to sex trafficking charges and denies grooming girls for sex with Jeffrey Epstein.
A week ago, her lawyers suggested jail was having a "deleterious effect on her health" and she may not be "strong enough" to stand trial in July.
Ms Strauss said Ms Maxwell's lowest observed weight had been 133lb and she was now 137.5lbs, which was "normal" for her height of 5ft 7ins.
She added that Ms Maxwell had "received a Covid-19 vaccine and is now fully vaccinated" and was "physically healthy".
Prosecutors said Ms Maxwell was being given more time to review documents than any other inmate at the jail in Brooklyn - 13 hours a day, seven days a week.
For all that time she had access to a desktop computer, and a laptop, in a day room away from her cell, and was able to email her lawyers.
She also had access to "a television, a phone on which to place social or attorney calls, and a shower".
Her lawyers have complained about a flashlight being shone in her cell every 15 minutes at night by guards.
But prosecutors said it was required to make sure she was breathing, and was shone at the ceiling.
Ms Strauss said: "The defendant wears an eye mask when she sleeps, limiting the disturbance caused by the flashlight."
Prosecutors said they have now disclosed 2.7 million pages of evidence to Ms Maxwell's lawyers, who have the option to visit her in person.
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