"If you add Salmonella to mashed up leaves, it's not surprising that it grows - anything will. When you damage cells you release nutrients," she said at HorticultureWeek.co.uk.
"But that doesn't reflect what actually happens. The industry doesn't use damaged leaves - they are inspected to ensure leaves are intact, and washed to remove any exudate as well as soil. Good agricultural practice ensures Salmonella doesn't get in in the first place. And it's a chilled, limited-life product."
She added she was "bemused" by the research, which "doesn't add to our knowledge".
The research, by microbiologists at the University of Leicester and Campden BRI, supported by BBSRC and published in Applied and Environmental Microbiology, found that just a small amount of damage to salad leaves could massively stimulate the presence of Salmonella, which could not then be removed by washing.
Lead author Dr Primrose Freestone said: "This strongly emphasises the need for salad leaf growers to maintain high food safety standards as even a few Salmonella cells in a salad bag at the time of purchase could be become many thousands by the time a bag of salad leaves reaches its use-by date, even if kept refrigerated."
Salmonella was the food-borne pathogen that caused the greatest number of hospital admissions in the UK last year.
BBSRC chief executive Professor Melanie Welham said: "Pathogens like Salmonella are serious bacterial threats that affect our health which is why BBSRC invests in research to understand and combat food poisoning."
The NHS Choices website responded to the publication by saying: "The results don't show that all packaged salad leaves are contaminated with gut bacteria like salmonella.
"What they do show is that if the bags have been contaminated with gut bacteria, these bacteria will replicate, even in the fridge, and there's little you can do to remove them. But any risk of food poisoning is far outweighed by the health benefits of eating fresh veg, such as reducing the risk of heart disease, stroke and some cancers."