Atlanta (CNN) -- The number of deaths linked to a listeria outbreak in cantaloupe has risen to 29, the Centers for Disease Control reported Wednesday, topping a 1985 mark for the most deaths among adults and children.
The outbreak, first detected in September and traced back to a Colorado farm, has sickened a total of 139 people in 28 states, the CDC says. In addition to the 29 deaths, one woman who was pregnant at the time she fell ill suffered a miscarriage.
The toll makes the current outbreak the deadliest among adults and children since the agency started keeping track of listeria cases in 1973, though a 1985 outbreak in California involved 28 deaths and another 20 stillbirths and miscarriages, CDC spokeswoman Lola Russell said, according to CDC figures.
The U.S. Food and Drug Administration has said it is unable to pinpoint the reason for the outbreak, but unsanitary conditions in a packing facility in the Granada, Colorado, farm is a suspected contributing cause.
The agency notified Jensen Farms in October that likely causes included packing equipment that "was not easily cleaned and sanitized" and the use of washing and drying equipment for cantaloupe packing as well as other raw agricultural commodities.
In addition, the agency said in a statement, the facility lacked a "pre-cooling step" to remove field heat from the cantaloupes before cold storage, possibly leading to condensation in the cooling process that promoted growth of the listeria bacteria.