Researchers in Slovenia have described results from a long-term, national Clostridioides difficile food surveillance project. Positive results were found in meat, fresh produce and poultry.
The three-year period of testing revealed a low proportion of Clostridioides — formerly Clostridium — difficile contaminated food and high genotype variability. As the risk of infection associated with Clostridioides difficile contaminated food is unknown, no measures were recommended for positive results.
Because of an increasing association between Clostridioides difficile and food, in 2015, the Administration of the Republic of Slovenia for Food Safety, Veterinary Sector and Plant Protection (UVHVVR) included it in national food surveillance. In Slovenia, the number of cases increased from 316 in 2013 to 665 in 2017.
Retail minced meat and meat preparations such as beef, pork and poultry were sampled from 2015 to 2017. They were collected at food markets and grocery stores in all Slovenian regions. Selected raw retail vegetables, leaf salads and root vegetables, and ready-to-eat salads were sampled during 2016 and 2017 and seafood only in 2017.
18 foods positive from several countries
Altogether, 434 samples were tested, with 12 of 336 raw and minced meat samples and six of 98 raw vegetables contaminated with Clostridioides difficile. Results were published in the journal Eurosurveillance.
Samples included raw poultry meat, meat preparations from poultry, minced pork and/or beef meat, meat preparations from pork and/or beef, shrimp and bivalve mollusks. Vegetable samples included different types of raw green leafy salads, ready-to-eat salads and root vegetables such as carrots, parsley and beetroot.
Of 319 meat and meat preparation samples, 266 were labelled made in Slovenia, 21 made in Austria, 11 made in Croatia, nine made in Germany and one each for Hungary and Denmark.
Samples of shrimp originated from Lithuania, Denmark, Ecuador and the Czech Republic, while all bivalve mollusks came from Slovenia. Of the 98 vegetable products, most were labelled made in Slovenia. Eight were made in Italy, two in Poland and one each from Austria, Croatia, Hungary, Germany, the Netherlands and Spain.
In 2015, three of 119 meat samples tested positive for Clostridioides difficile, five of 130 samples in 2016 and four of 87 meat and seafood samples were positive in 2017. Of the 12 positive samples, five were poultry preparations, three beef and/or pork meat preparations, three raw poultry and one bivalve mollusk. Ten of these were made in Slovenia and two in Austria.
For retail fresh vegetables, in 2016, two of 48 tested samples were positive and four of 50 samples tested positive in 2017. Of these six positives, three were raw leaf salads, one was parsley and two were ready-to-eat salads. Vegetables from three positive samples were grown in Italy, two in Slovenia and one in Poland.
Yearly increase for positive samples
For meat, the most direct way of Clostridioides difficile contamination is fecal during slaughtering, but post-production processing could play a role. For poultry it could be a post-slaughter contamination source in the production line. The main sources of vegetable contamination are soil or indirect fecal contamination via irrigation or manuring. A possible source for meat and vegetables could also be via contaminated hands during handling.
The study found the proportion of Clostridioides difficile positive meat and vegetable samples increased every year.
“However, the number of tested samples was too low to speculate on any possible trends. The changes in samples sizes and produce types could have contributed to this observation,” said researchers.
Given the low detected prevalence of contaminated samples, the food safety risks for the tested food types are likely very low.
“On the other hand, although the levels of food contamination with Clostridioides difficile spores are usually low, the constant exposure to the low spore levels in combination with a disrupted gut microbiota or immune incompetence could represent increased risk for Clostridioides difficile infection.”
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