Salads and spinach, which are sold ready-cut in a plastic bag, significantly increase the possibility of infection with the bacteria salmonella, according to a new study by scientists in Britain, with the participation of a young Greek researcher.
Laboratory analyses showed that the juices secreted from the cut leaves, due to their moisture and nutrients, constitute a suitable medium for the development of the dangerous microorganism, which can even be fatal.
The researchers also discovered that the presence of the juices makes salmonella more aggressive and thus increases the risk of infection to the consumer. The risk can dramatically increase up to 2,400 times.
The researchers, led by microbiologist Dr. Primrose Freestone of the University of Leicester and PhD researcher Yiannis Koukkidis, made the relevant publication in the journal "Applied and Environmental Microbiology".
Scientists have found that even tiny amounts of juice, no larger than one two-hundredth of a teaspoon, that escape from the cut heads of lettuce and spinach and remain inside the plastic bag, make it easier for salmonella to multiply, even when the package is in the fridge.
In fact, the bacterium adheres so firmly to the cut leaves that it does not go away when washed by the consumer. A few salmonella cells at the beginning of the package are enough to have grown to many thousands by the time the consumer eats the product or by the time it expires. The initial 100 salmonella bacteria can have become 100,000 in just five days from the initial cutting of the salads to be packed.
The researchers pointed out the need to eat these packaged cut fresh vegetables as soon as possible after opening them. Once the plastic bag containing them is opened, salmonella bacteria grow even faster than when refrigerated.
In fact, the researchers found that salmonella can grow even when the refrigerator is cooled to 4 degrees Celsius and not 5.2 degrees, as was believed until now.
In recent years, there have been several incidents of food poisoning from salmonella and coliforms in fresh salads both in Europe and in the USA. This fact, according to scientists, means that producers and packers of such fresh packaged products must adhere to the highest standards of hygiene.
Salmonella contamination of lettuce and vegetables can occur from contact with an animal or insect, from soil, from contaminated water during field irrigation, or from contaminated equipment or workers' hands when cutting and packing the produce.
In any case, according to the experts, all fresh products, packaged or not, need to be washed very well before they are consumed. Usually packaged salads are pre-washed with chlorinated water. Chlorine reduces the presence of pathogenic microorganisms, but does not eliminate them.
The researchers recommended that consumers buy freshly cut salads and eat them the same day they are purchased. Researchers in the US who have taken samples have found 0% to 3% of packaged salads to be contaminated, according to the BBC.
Kimonas Andreas Karatzas, also of Greek origin, lecturer in food microbiology at the British University of Reading, emphasized that consumers should prefer uncut salads to pre-cut ones.
Source: Ethnos Online
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