I’m an ex-USDA food expert – here’s how to avoid stomach bugs when eating on vacation and cruises

A stomach virus is the last thing anyone wants on vacation – forced to spend their days off huddled over a toilet. 

But a food safety expert told DailyMail.com that could be the reality for hundreds of people getting away on cruise ships. 

Dr Darin Detwiler, leading food safety expert in the US, told DailyMail.com viruses like E.coli, salmonella and norovirus are common on cruise ships because of cramped quarters, the thousands of people on board and the high volume of communal food. 

The highly contagious infections are spread through contaminated food, water or improper food handling, and cause abdominal cramps, vomiting, diarrhea, fever, chills and fatigue. 

In severe cases, those sickened may become dehydrated or go into organ failure and need to be hospitalized.

The CDC’s Vessel Sanitation Program (VSP) tracks and inspects outbreaks of gastrointestinal illnesses on cruise ships and in 2024, the agency has recorded 10 incidents, affecting 1,040 passengers.

Of those outbreaks, seven were caused by norovirus, while three were caused by either salmonella or E. Coli.

These viruses are commonly caused by ingesting water or food that has been contaminated with feces, or consuming undercooked food, such as meat, eggs or fish. The viruses can then spread when someone comes into contact with an infected person or a surface a sick person has touched.

Overall, the CDC estimates between two to four percent of cruise passengers experience these illnesses each year. 

And with an estimated 31.7million people sailing globally, more than 500,000 could be sickened.

Cruise ships face ‘unique challenges’ when it comes to food safety, Dr Detwiler notes, ‘particularly because they serve large numbers of passengers in enclosed spaces where illnesses can spread quickly. They are like floating cities.’

He added: ‘Cruise ships also typically source food internationally, stopping at various ports to replenish supplies. This can result in varying safety standards, especially when it comes to fresh produce, meats, and seafood.’

While most gastrointestinal illnesses involve mild symptoms, vulnerable populations – such as young children, the elderly, and pregnant women – can face more serious complications like severe dehydration, organ failure, ‘or in extreme cases, death.’

To reduce the chances of getting sick while at sea, the university professor told this website his seven safety measures.

WASH HANDS OFTEN, THE OLD FASHIONED WAY

The most effective way to prevent infections on cruise ships, Dr Detwiler said, is by washing your hands with soap and water on a regular basis for 20 seconds, or the length of two happy birthday songs. 

He noted this is a particularly important thing to do before meals. 

While alcohol-based hand sanitizers are ‘helpful,’ these can be ‘less effective against norovirus, so prioritize handwashing.’ 

In a bid to get young children into the habit of washing their hands, Dr Detwiler recommended educating them around stomach bugs and the possibility of getting sick. 

AVOID THE BUFFET AT PEAK TIMES  

Buffets are known to be hotspots for contamination, especially when food is left out for long periods. 

To minimize risk, Dr Detwiler advises dining during off-peak hours ‘when food turnover is higher, or opt for made-to-order items.’

During peak times, there is more risk of contamination as people crowd around food stations.  

The CDC stresses hot food should be ‘steaming,’ while the cold food should be visibly chilled. 

The agency said: ‘Germs that cause food poisoning grow quickly when food is in the danger zone, between 40 degrees Fahrenheit and 140 degrees Fahrenheit.’

These temperatures allow bacteria to multiply more quickly, with norovirus and E. Coli germs set to flourish.

Norovirus is the most common type of stomach bug and typically occurs when a sick person touches food before serving it. However, foods like fish and seafood can be naturally contaminated with it. 

While most people recover without any complications, severe vomiting and diarrhea can lead to dehydration, requiring medical care. 

E.coli is a bacteria that causes similar symptoms. It can also be in raw and undercooked meats. Most strains are mild but some may cause severe cramping and bloody diarrhea. 

OBSERVE HOW FOOD IS BEING PREPARED

While visiting buffet stations on the ship or other dining areas, Dr Detwiler told DailyMail.com it’s important to look at how the food and drinks are being prepared. 

Some of his pet peeves are servers not wearing gloves, unclean serving spoons and foods stored at the wrong temperatures. 

Meanwhile, at the cruise ship bars, he said drink garnishes should be avoided.

A 2007 study published in the Journal of Environmental Health found almost 70 percent of lemon slices used as bar garnishes were contaminated with bacteria.

Dr Detwiler says if you see unsanitary activities while cruising, ‘it is very important to speak up and say something.’

SKIP THE OYSTERS AND STEAK TARTARE

While raw bars, stocked with everything from oysters to clams, are considered an extravagant dining option at sea, Dr Detwiler advises keeping clear of them. 

In fact, he recommends skipping raw or undercooked foods all together because of possible contamination.

He explained: ‘Raw seafood and undercooked meats, such as steak tartare or ribeyes cooked rare, are more likely to carry pathogens. You even run a risk with runny eggs. 

‘Opt for well-cooked dishes to reduce the risk of exposure to salmonella or listeria.’ 

People with salmonella develop stomach issues and a fever, which can become severe and require hospitalization.

Many of these foods can also harbor Listeria, which is usually found in unpasteurized milk, soft cheeses, ready-to-eat foods, fish, cured meats and pre-cut fruit.

Most people with listeria will not fall seriously ill. But in some cases, it can cause confusion and seizures, miscarriage in pregnant women, and even death.

STICK TO BOTTLED WATER AND BE WARY OF ICE 

Even though cruise ships purify their water, Dr Detwiler said bottled water is a ‘much safer option and worth paying a bit extra for.’ 

This is because cruise ship water could be contaminated with enterotoxigenic Escherichia coli (ETEC), a type of E. coli bacteria that can cause diarrhea. It can also be the source of legionella, a bacteria that can cause legionnaires’ disease.

Legionnaires’ is a serious type of pneumonia that can cause shortness of breath, as well as gastrointestinal symptoms. About 10 percent of people who contract the disease die.

For this reason, you should also consider forgoing ice in your drinks if you can, Dr Detwiler told DailyMail.com.  

He added: ‘Be cautious about drinking tap water or using ice, particularly when docked in foreign ports where water quality may vary.’

CUT AND PEEL YOUR OWN FRUIT

While slices of melon and chunks of pineapple might look alluring on the buffet counters, Dr Detwiler reveals that ‘pre-cut fruits carry a risk of being exposed to bacteria.’

In recent years there have been several outbreaks of bacteria linked to fruit. Most recently, in 2023, there was a nationwide outbreak of salmonella linked to cantaloupes, with 407 people sickened and six deaths.

For this reason, Dr Detwiler says he will ‘always avoid cantaloupe due to how often it becomes contaminated and causes illnesses and deaths.’

Instead of cut fruit, he recommends selecting whole fruits from dining areas and ‘cutting or peeling it yourself to avoid contamination.’

SKIP STREET FOOD ON LAND

The risk of stomach illnesses on cruises extends beyond the ship.

Most cruise companies offer shore excursions, where vacationers leave the ship and explore an area for the day, giving people an opportunity to sample local cuisine.

But Dr Detwiler warned against street food, especially when high temperatures can serve as a breeding ground for harmful bacteria.

He says: ‘When exploring at port stops, be mindful of food safety standards in local markets. 

‘Stick to reputable restaurants and avoid street food that may not meet the same hygiene levels as the cruise.’