Does danger lurk in salad bags?

does danger lurk in salad bags

Salad bags are quick and easy.  BUT, that convenience might come at a price, say the experts.

The bagged salad leaves in the supermarket fridge look nice and crisp, they are pre-washed, and they have a distant sell-by date. What’s not to like? It saves time and it seems healthy.

Food producers worldwide are under pressure to deliver more food and to do so cheaply. Customer appeal and profit margins are major motivators – not necessarily customer health or the nutritional value of the produce. Sometimes food safety regulations are also overlooked.

Unsafe food containing harmful bacteria, viruses, parasites or chemical substances can cause more than 200 diseases and kill 230 000 people every year, says the World Health Organisation. But only in a perfect world can there be perfect food safety.

Here’s why bagged salads are in the health spotlight:

  • The minute produce is picked, it starts losing nutrients. Salad in the supermarket fridge might look great even after five days, but its nutritional value might be significantly reduced.
  • The main aim of the so-called modified atmospheric pressure (MAP) process is to reduce the spoilage of the salad and to extend the shelf life of the food.  It is certainly not to protect the nutrients. This process can reduce levels of certain antioxidants such as vitamin C and vitamin E.
  • All produce – not just salads – are at risk of carrying micro-organisms from the environment. This goes for organic produce as well. Bagged salads are often washed in low-chlorine rinse to inhibit bacterial growth (such as E.coli and salmonella).  At the same time, however, it also affects the nutrients negatively. But, any rinsing of leaves, even in your own kitchen, will reduce nutrient levels.
  • This chlorine rinse doesn’t always kill the bacteria in salads.  In fact, the ones that survive the chlorine rinse can sometimes thrive inside plastic bags. Researchers from Tufts University found that after five days juice released from crushed leaves in salad bags nourish the salmonella bacteria, which also attach to the sides of the plastic bags.

The final verdict

Bagged salads are better than no salad at all, but the fresher the better.

Always check the sell by dates. Don’t keep the salad in the fridge for more than a day or two before using it. Always steer clear of bags that appear too puffy – the contents may be off. Give the bagged salad contents a quick rinse before serving it.

And if you can find fresh, unbagged produce, choose that.


By Susan Erasmus


UC Berkeley School of Public Health

World Health Organization

Applied and Environmental Biology

Chilled Food Association


The Content on this site is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.


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