Researchers have described the first outbreak of apple juice-related cryptosporidiosis reported outside the United States.

Although it did not involve many people, it serves as a reminder that apple juice, and other beverages, may serve as transmission vehicles for cryptosporidiosis and appropriate hygiene measures are essential in the production of juice, according to the study published in Epidemiology and Infection.

All apple juice associated outbreaks have been reported from the U.S., with the last one in 2003. More recent outbreaks of foodborne cryptosporidiosis have been linked to salad vegetables or herbs.

In the autumn of 2018, an outbreak of cryptosporidiosis affected six employees from the same company in Western Norway. The organism was Cryptosporidium parvum. All those infected had drunk from the same container of self-pressed apple juice.

Patients were absent due to illness and had similar symptoms including violent diarrhea, abdominal pain with severe colic, cough, pain in the thighs, pelvis, and back, exhaustion and fatigue. Cryptosporidiosis was diagnosed in individuals via samples provided to their general practitioners. In all of those infected, diarrhea and other symptoms continued for at least one week, before gradually subsiding and for some symptoms persisted for up to two to three weeks.

Those ill had drunk freshly pressed apple juice brought in to work the previous Monday by one of those who was sick. Apple juice had been made by the employee during the previous weekend, with apples picked in the orchard of her family’s farm, and pressed at a neighboring farm. How the juice became contaminated was not identified.

The 5-liter container of apple juice had been left in a communal area for everyone. Retrospective questioning of employees identified seven who had cups of juice from the container. All six cases were among those who had the apple juice.

In early November, a fecal sample from one of the patients and a 1.5-liter sample of apple juice not from the same container from the workplace were received at the Parasitology Laboratory, Norwegian University of Life Sciences, and analyzed for Cryptosporidium oocysts. The fecal and apple juice sample was positive. only a few oocysts were found in the fecal sample as might be expected at the end of infection but large numbers (estimate of hundreds) were found in the apple juice concentrate.

A total of around 200 liters of apple juice was made and collected into previously unused 5-liter volume containers. These containers were divided amongst those who had picked and pressed the apples.

However, there were no other reports of infections associated with the apple juice in other containers. One was shared with colleagues at another workplace, without anyone becoming ill, indicating the contamination did not extend to the entire 200 liters and was limited to a couple of containers suggesting only a few apples used to make the juice had been contaminated.

Infections resulted after consumption from only one of 40 containers of juice. It seems that although Cryptosporidium oocysts were detected in a sample from another container, contamination did not affect the whole batch.

It was speculated a couple may have been dropped during collection and then retrieved; if by misfortune they had landed in an area of high contamination, then there could have been localized high contamination in a few apples. Although there was the possibility to wash them before pressing, spiking experiments have indicated it is difficult to remove Cryptosporidium oocysts from the surfaces of apples.

Another route could have been the equipment was contaminated before use, and oocysts were washed into the initial containers of apple juice. There is no evidence for this and there were no reports of illness by others using the press.

Despite this, the apple press owner reported the intention to implement the use of a high-pressure hot water cleaner for use between apple lots and customers to assist in and improve the equipment cleaning process.