John's Journal

Hey, I made a mistake in yesterday's list. Francis Beckwith of Baylor University was initially denied tenure, but the denial was reversed on appeal and he continues to teach at Baylor to this day. I apologize for the omission.

Ten food-borne pathogens and how they can be inactivated or destroyed:

1. Yersinia enterocolitica: Potassium sorbate at pH 5.5 concentrations above 1000 ppm virtually eliminates growth or causes inactivation depending on dose.
2. Shigella: Rapidly inactivated at temperatures above 65°C.
3. Toxoplasma gondii: Exposure of tachyzoites to 70 J m-2 ultraviolet light renders the organism non infectious. A dose of 1 kGy would ensure that pork is free of the organism.
4. Escherichia coli O157:H7: A 2-3 kGy dose of ultraviolet light is sufficient to decontaminate meat.
5. Clostridium botulinum: Thermal death is accelerated at extremes of pH (<5.0 and >9.0) for type A spores; the toxin inactivates quickly at pH 11.
6. Cryptosporidium parvum: Milk pasteurisation is sufficient to inactivate oocysts (e.g. >99.9999% inactivation after 5 sec at 71.7°C).
7. Listeria monocytogenes: Inactivated at pH values less than 4.4 at rates depending on the acidulant and temperature. Organic acids, such as acetic, are more effective than mineral acids (e.g. hydrochloric).
8. Giardia intestinalis: Heating cysts to 60-70°C for 10 minutes, or boiling for 3 minutes, inactivates them.
9. Vibrio parahaemolyticus: Cooking to an internal temperature of 65°C effectively inactivates this organism.
10. Bacillus cereus: Most chemical sanitisers used routinely in the food industry will destroy the organism on surfaces.

Today's list is for astrablue, who requested Yersinia enterocolitica. It also continues the tradition of mentioning a bacterium of the genus Vibrio in at least one list during Reader Request Month. The information above comes from microbiological pathogen data sheets prepared for the New Zealand Food Safety Authority by the Institute of Environmental Science and Research Limited, so I blame them for any errors. I also blme them for my inability to come up with a poem to post along with this list.