Saturday, February 26, 2011
WHY ARE CRUISE SHIPS RISKY PLACES TO EAT?
Alright, I still haven't really explained in recent blogs why cruise ships are among the riskiest places to eat. Mea culpa. So here goes.
Not every food borne illness originates on board a cruise ship. Some of the foods purchased for the cruise already carry contaminants (as was believed to be the case with contaminated shrimp served at the embarkation buffet on board one recent cruise). But the studies I have looked at suggest that most get into the food on board the vessel. Often people - crew or passengers - are involved in the spread of illness.
Here are some reasons:
• The mass preparation of food which is usually more prone to contamination ( whether done for catered events, nursing homes, schools, restaurants, conferences or cruise ships).
• The confined area and non-stop socializing among passengers, leading to close contact between people. This means that a crew member handling food can contaminate it, with several passengers (and maybe crew) becoming ill, and then these sick people will pass it on to others (as often happens in the case of Norovirus-caused illness), or, even contaminate more food (if crew members are involved, as they usually seem to be).
• The popularity of buffet service (often with passengers serving themselves): buffets are known to be especially risky type of food for a number of reasons (see future blog).
Investigation of on-board outbreaks has sometimes traced them back to just one ill crew member, which, by the end of the cruise, resulted in over a hundred, or several hundred, illnesses. The original carrier of an illness may also have been a passenger who came on board while ill (not wanting to miss a pre-paid cruise). He or she may then have passed it on to a crew member (cleaning up the mess) and from there to other crew members, including kitchen staff, and on to food and more passengers and crew.
Norovirus - the most common cause of gastrointestinal illness on board - is so very easy to pass on. Just a few viruses on a table surface, a fork or a lettuce leaf will do it. It is also extremely difficult to deep sanitize an infected ship if Norovirus is involved. I have looked at numerous cases in CDC records where the same ship was involved in repeated outbreaks in spite of all the efforts made.