The Massachusetts Department of Public Health on 27th December issued a warning to consumers who bought Whittier Farms dairy foods not to consume any of their milk products for the time being because there is a risk they could be contaminated with listeria bacteria.

©Chestnut Labs

Whittier Farms is a family run dairy business based in Shrewsbury, Massachusetts , USA, that provides fresh farm milk to consumers mostly via home delivery in the greater Worcester/Shrewsbury area.

Products affected include the following Whittier brands:
Balance Rock,
Spring Brook, and
Public health officials have identified four cases of listeriosis (infection by listeria bacteria) in a pregnant woman and three elderly residents, two of whom have died. DNA tests on the bacteria showed they came from a common source, and samples of dairy produce showed they were contaminated.

Whittier Farms has voluntarily suspended milk production and distribution. They said they were "extremely concerned about the situation", and were fully cooperating with the investigation to track down the source of the contamination. They were also alerting all their customers.

One infection happened in June, another in October and two in November, this year.

Dr Al DeMaria, Director of Communicable Disease Control at the Massachusetts Department of Public Health, said:

"Although evidence suggests that contamination is likely to be at a low level and the risk of infection low, even in those at high risk, it is recommended that consumers do not consume these products and discard any of these products they have."

Listeriosis can be life-threatening to certain vulnerable groups such as pregnant women, those with compromised immune systems, the elderly, new born babies, and sometimes healthy individuals.

The illness is usually mild and symptoms, which are often described as flu-like, include fever and muscle aches. In some cases these are accompanied by gastrointestinal symptoms such as nausea or diarrhea.

The bacterium's full name is Listeria monocytogenes. It is commonly found in soil and water, and farm products become contaminated in various ways.

For example, vegetables can become contaminated from the soil or from manure used as fertilizer. Animals can become contaminated without showing symptoms and in turn contaminate animal products such as milk and meat.

Listeria is found in raw foods such as uncooked meats and vegetables, and also in processed foods that become contaminated after processing. These include soft cheeses and cold deli cuts. Unpasteurized or "raw" milk or its products can also be a source.

The bacteria are normally killed when contaminated foods are pasteurized or cooked, but these can become contaminated again after processing. This is probably how listeria gets into ready to eat foods such as hot dogs and deli meats.

The US Centers for Disease Control and Prevention (CDC) suggest you take the following precautions to avoid listeria infection:
Cook raw meat such as beef, pork, chicken, thoroughly.

Wash raw vegetables thoroughly before you eat them.

Keep uncooked meat separate from cooked and ready to eat foods and from vegetables.

Avoid eating unpasteurized milk and milk products.

Wash hands, cutlery, kitchen tools, cutting boards after handling uncooked foods.

Eat perishable and ready to eat food as soon as possible.
There are some 2,500 reported cases of listeriosis in the US every year. Last year (2006) there were 22 cases in the state of Massachusetts.

Whittier Farms operate 500 acres of New England farmland, 300 head of registered Holstein cattle, a processing plant, and two milk stores.