How does Salmonella contaminate pre-cut melon?

A recent outbreak in the US of Salmonella-contaminated pre-cut melon infected at least 93 people (reported). This was unfortunately not the first outbreak due to contaminated pre-cut melon with pathogenic bacteria. This prompts the question of how does Salmonella contaminate pre-cut fruits?

Salmonella outbreaks are generally associated with foods such as raw chicken and eggs. Fruit is not considered a “natural” vehicle for Salmonella. This means that the fruit had to become contaminated at some point in the production process. Meaning somewhere between farm to fork.

Farm workers or handlers that are ill are amongst some of the possible causes of such contamination.

Possible Causes of Salmonella Contamination

  • Contaminated irrigation water
  • Contact from animals of animal products
  • Poor handling, processing or transport
  • Contaminated equipment could have presented the opportunity for the bacteria to get on the fruit.

Most people infected with Salmonella develop the following signs and symptoms 12 to 72 hours after eating a contaminated product:

  • Diarrhoea
  • Fever
  • Abdominal cramps

The surface of melon fruits are webbed, and offer perfect hiding places for pathogens. As such they are difficult to clean since bacteria attach to rough surfaces and in small crevices. Bacteria such as Salmonella can form biofilms, which is a protective film or layer that bacteria form, which can shield them from cleaning.

When the fruit is sliced, cut or processed the bacteria has access to the flesh or inside of the fruit, which allows the bacteria to grow and contaminate the produce.

Melons are typically not cooked and eaten raw, thus providing no opportunity to kill the bacteria using heat. Food manufacturers must be aware of the risk of Salmonella contamination of foods, and should, therefore, take preventative measures.

Washing fruits and vegetables before cutting and slicing is a critical way to prevent contamination of these food products. Ensuring a good hygiene and food safety system is in place with regular microbiological testing are essential ways to manage possible outbreak risks.

Lastly, instilling a food safety culture in the food industry will go a long way in preventing future outbreaks from happening.


Learn More About Salmonella

kitchen hygiene audits
microbiology testing

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Hygiene Consultant