Survival of Cryptosporidium species in environments relevant to foods and beverages.
OBJECTIVE
To provide data on the survival of Cryptosporidium oocysts in a range of conditions relevant to foods and beverages.


RESULTS
Cryptosporidium parvum and C. hominis oocysts were stored in buffered media at different pH values and with various acids. In addition, neutral solutions with high salt (4.5% w/v), glycerol (20% v/v), sucrose (50% w/v) or ethanol (9 and 40% v/v) were used to determine their effects on survival. After storage periods of between 1 h and 14 days, viability was assessed using sporozoite ratio or infection of MRC-5 cell monolayers (not previously reported for culture of this organism). With all treatments, and with both assay techniques, viable oocysts were found at the end of the storage periods. However, treatments with one of the following additions: high salt, glycerol, sucrose or ethanol showed a negative and statistically significant effect on survival. Decline was noted after 1 day or even 1 h of treatment.


CONCLUSIONS
MRC-5 cells are suitable for infection by C. parvum and C. hominis. Both tissue culture and sporozoite ratio gave broadly similar survival results and the greatest effects were seen with addition of components which reduced water activity.


CONCLUSIONS
This study has provided useful additional information to the food industry when considering the risk posed by this organism.
Dawson
D J
DJ
Department of Microbiology, Campden and Chorleywood Food Research Association, Chipping Campden, Gloucestershire, UK. d.dawson@campden.co.uk
Samuel
C M
CM
Scrannage
V
V
Atherton
C J
CJ
D000818:Animals; D001628:Beverages / Q000469:parasitology*; D002460:Cell Line; D003458:Cryptosporidium / Q000187:drug effects / Q000254:growth & development* / Q000472:pathogenicity; D003470:Culture Media; D046508:Culture Techniques; D000431:Ethanol / Q000494:pharmacology; D016266:Food Parasitology; D005990:Glycerol / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D033661:Oocysts / Q000254:growth & development; D012965:Sodium Chloride / Q000494:pharmacology; D034101:Sporozoites / Q000254:growth & development; D013395:Sucrose / Q000494:pharmacology
D003470:Culture Media; D000431:Ethanol; D012965:Sodium Chloride; D013395:Sucrose; D005990:Glycerol