Salmonella is an organism which can cause serious and sometimes fatal infections in young children, frail or elderly people, and others with weakened immune systems. Last year the Salinas Valley was in the forefront of a salmonella outbreak, which was traced to bagged baby spinach. That outbreak had killed three people and had sickened hundreds before it was finally contained.

Salmonella is often the culprit in food poisoning. Some of the symptoms include diarrhea, stomach ache as well as insidious fever. Although the bug is not usually fatal, the very old and the very young are at a high risk. Around 40,000 Americans are affected by some sort of food poisoning involving salmonella each year. It is estimated that 600 die as a result of this infection.

In the present case, Metz said that over 90 percent of the spinach was not sent to stores at all. The implicated products are 10- and 16-ounce bags, 4-pound cartons, and cartons containing four 2.5-pound bags. The company said that these cartons bear the tracking codes 12208114, 12208214, or 12208314.

Metz said the cartons that were distributed went to continental United States as well as Canada. It urged consumers who had purchased the suspected products to either throw them away or return them to their nearest store for a refund.

The company said it has complied with the California Leafy Green Products Handler Marketing Agreement. This agreement was put into effect after last year's outbreak.

However consumer advocates are still calling for stricter monitoring of the situation. Produce safety has assumed greater importance in the United States following a slew of product recalls. Just this week Mars Petcare recalled two dry dog food products following fears of contamination by Salmonella Schwarzengrund.

The U.S. Centers for Disease Control and Prevention (CDC) has received reports of 64 cases of illness in humans related to Salmonella Schwarzengrund. However none of these can be attributed to the recalled product.

Earlier this year, salmonella was also implicated in Peter Pan peanut butter across 39 states in the US. Although no casualties were reported, at least 20 percent of the people who were infected had to be hospitalized.

Salmonella is a mean bug if left untreated. The increasing number of product recalls bears testimony to the fact that better detection systems are in place. It also raises the question whether these systems are adequate enough to protect produce from contamination.

According to the Centers for Disease Control and Prevention, the following measures should be undertaken to prevent salmonella infection:

* Cook poultry, ground beef, and eggs thoroughly before eating. Do not eat or drink foods containing raw eggs, or raw unpasteurized milk.
* If you are served undercooked meat, poultry or eggs in a restaurant, don't hesitate to send it back to the kitchen for further cooking.
* Wash hands, kitchen work surfaces, and utensils with soap and water immediately after they have been in contact with raw meat or poultry.
* Be particularly careful with foods prepared for infants, the elderly, and the immunocompromised.
* Wash hands with soap after handling reptiles or birds, or after contact with pet feces.
* Avoid direct or even indirect contact between reptiles (turtles, iguanas, other lizards, snakes) and infants or immunocompromised persons.
* Don't work with raw poultry or meat, and an infant (e.g., feed, change diaper) at the same time.
* Mother's milk is the safest food for young infants. Breast-feeding prevents salmonellosis and many other health problems.