Here's the continuing saga on the Listeria outbreak associated with melons. Very Sad - 2 more deaths:

The death toll has risen to 8 in an outbreak of listeria traced to Colorado-grown cantaloupes, officials said Wednesday [21 Sep 2011].

The CDC said that a person in Maryland died from eating the tainted produce. Four deaths have been reported in New Mexico and 2 in Colorado, and one person has died in Oklahoma.

The CDC said 55 people in 14 states have now been confirmed as sickened from eating the cantaloupes. On Mon 19 Sep 2011, the CDC reported 4 deaths and 35 illnesses in 10 states.

The death count, the highest in a known food outbreak since tainted peanuts were linked to 9 deaths almost 3 years ago, could go even higher. The CDC said illnesses in several other states potentially connected to the outbreak were under investigation.

Health officials have said they think the number of illnesses and deaths could continue to grow because the incubation period for listeria can be up to a month. Unlike many pathogens, listeria bacteria can grow at room and refrigerator temperatures. The FDA and CDC recommend anyone who may have one of the contaminated cantaloupes throw it out immediately.

About 800 cases of listeria are found in the United States each year, according to CDC, and there usually are 3 or 4 outbreaks. Most of these are traced to deli meat and soft cheeses, where listeria is most common. Produce has rarely been the culprit, but federal investigators say they have seen more produce-related listeria illnesses in the past 2 years. It was found in sprouts in 2009 and celery in 2010.

While most healthy adults can consume listeria with no ill effects, it can kill the elderly and those with compromised immune systems. It is also dangerous to pregnant women because it easily passes through to the fetus. In the current outbreak, the median age of those sickened is 78, according to the CDC.

Here's a gram stain of Listeria: small gram positive rods. Interestingly enough...it LIKES to grow at room temperatures and does just fine in the refrigerator, just grows slower. it's named after Joseph Lister who promoted the idea of sterile surgery while working at the Glasgow Royal Infirmary. He successfully introduced carbolic acid (now known as phenol) to sterilize surgical instruments and to clean wounds, which led to reducing post-operative infections and made surgery safer for patients.
It's a small world. Speaking of which....here is a wonder blog: Small Things Considered (from the ASM website. ASM=American Society for Microbiology). link: http://schaechter.asmblog.org/schaechter
I highly recommend it.