[Infection risks associated with importation of fresh food in Iceland]. / Innflutt fersk matvæli og sýkingaráhætta fyrir menn.

Access to safe food is a privilege for people living in Iceland. Rapid increase in antimicrobial resistance, related to factory farming and antimicrobial use in agriculture, is a major threat to public health. Increasing food trade between countries and continents facilitates global spread of pathogens and resistance. Icelandic agriculture has benefitted from its isolation and small size. After interventions to reduce the prevalence of Campylobacter and Salmonella at poultry farms, the incidence of human campylobacteriolsis is 17-43/100.000, of which about half is domestically acquired and Salmonella infections 10-15/100.000 mainly acquired abroad. Since Enterohaemorrhagic E. coli (EHEC) has not been detected in domestic cattle, the low incidence of infections is not surprising (0-0.6/100.000/year). A recent outbreak due to a multiresistant EHEC strain was traced to imported lettuce. Antimicrobial use in Icelandic agriculture is among the lowest in Europe and domestic infections caused by Salmonella and Campylobacter are rarely caused by resistant strains. Carbapenemase producing Enterobacteriaceae have not been found in Iceland. Low use of antimicrobials in Icelandic agriculture and actions to limit the spread of Campylobacter and Salmonella have been successful. The public should be informed of the importance of the origin of food and that Icelandic food products are among the safest.

Broiler Campylobacter contamination and human campylobacteriosis in Iceland.

To examine whether there is a relationship between the degree of Campylobacter contamination observed in product lots of retail Icelandic broiler chicken carcasses and the incidence of human disease, 1,617 isolates from 327 individual product lots were genetically matched (using the flaA short variable region [SVR[) to 289 isolates from cases of human campylobacteriosis whose onset was within approximately 2 weeks from the date of processing. When there was genetic identity between broiler isolates and human isolates within the appropriate time frame, a retail product lot was classified as implicated in human disease. According to the results of this analysis, there were multiple clusters of human disease linked to the same process lot or lots. Implicated and nonimplicated retail product lots were compared for four lot descriptors: lot size, prevalence, mean contamination, and maximum contamination (as characterized by direct rinse plating). For retail product distributed fresh, Mann-Whitney U tests showed that implicated product lots had significantly (P = 0.0055) higher mean contamination than nonimplicated lots. The corresponding median values were 3.56 log CFU/carcass for implicated lots and 2.72 log CFU/carcass for nonimplicated lots. For frozen retail product, implicated lots were significantly (P = 0.0281) larger than nonimplicated lots. When the time frame was removed, retail product lots containing Campylobacter flaA SVR genotypes also seen in human disease had significantly higher mean and maximum contamination numbers than lots containing no genotypes seen in human disease for both fresh and frozen product. Our results suggest that cases of broiler-borne campylobacteriosis may occur in clusters and that the differences in mean contamination levels may provide a basis for regulatory action that is more specific than a presence-absence standard.

The influence of freezing and duration of storage on Campylobacter and indicator bacteria in broiler carcasses.

In total, 215 commercially processed broiler carcasses were examined to determine optimum cultural enumeration, the effects of freezing, method of thawing, and duration of frozen storage on levels of Campylobacter spp. and fecal coliforms. Enumeration studies compared MPN procedures to direct plating onto selective mCCDA agar and indicated equivalency for quantitation of Campylobacter spp. Levels of Campylobacter and fecal coliforms were subsequently estimated by direct plating of carcass rinses. Freezing of naturally contaminated carcasses followed by storage at -20 degrees C for 31, 73, 122 and 220 days showed statistically significant (P< or =0.05) reductions in Campylobacter counts initially as compared with counts found on fresh product. Among 5 lots of broilers, levels of Campylobacter on carcasses were reduced by log mean values ranging from 0.65 to 2.87 after freezing and 31 days of storage. Similar reductions due to freezing were not observed for fecal coliforms counts. The level of Campylobacter was reduced by approximately one log immediately after freezing, and remained relatively constant during the 31-220 days of frozen storage. The levels were constant during 7 days of refrigerated storage. After 31 days of frozen storage there was a reduced rate in reduction of counts among broilers thawed at 7 degrees C as compared to thawing at 22 degrees C with either cultural method (MPN and mCCDA). These findings warrant consideration of the public health benefits related to freezing contaminated poultry prior to commercial distribution to reduce Campylobacter exposure levels associated with contaminated carcasses.