Food-Borne Pathogens: E. Coli

Introduction

Continuing my series on food-borne pathogens, we are taking a look at a more fragile pathogen, E. Coli. While not as life-threatening as C. Botulinum, E. Coli can still cause a fair bit of duress.

Sources of E. Coli

E. Coli is found most readily in the guts of animals such as cows, sheep, and deer. Because of this, the main source of contamination is cattle manure. Poor personal hygiene can also cause infection.

The Danger

According to the CDC, symptoms of E. Coli infection often include severe stomach cramps, diarrhea, and vomiting. Sometimes this is also accompanied by a low fever (less than 101°F/38.5°C). Recovery generally occurs within 5 to 7 days. (E.coli [Escherichia coli]) As with most infections, E. Coli can be dangerous to those with an underdeveloped/compromised immune system, as well as the very young or very old.

Prevention in Food Preservation

Much like C. Botulinum, E. Coli prevention needs to be thought of from two fronts: Preventing growth, and decreasing survivability.

E Coli Growth

Temperature for Growth: 7°~46°C
Lowest pH for Growth: 4.4~9.0
Atmosphere: Can grow in a vacuum, but can be inhibited using CO₂
Water Activity (lower is “drier”): Minimum: 0.950,
Optimum: 0.995
(E. coli Risk Profile)

Management in Period Cookery

The simplest way of dealing with E. coli is by cooking thoroughly. A few minutes at 70°C will render most of the pathogen inactive. Lactic acid fermentation also proves effective at a pH of 4.5. While drying is no guarantee of safety, salt can be used to inhibit growth, with increasing amounts increasing the temperature threshold of the inhibiting effect.

Fermented goods, such as sauerkraut and certain varieties of pickle, provide a suitable defense against E. coli through high levels of salinity and low pH through the use of lactic acid. Cured meats, while effective in their own right (by similar methods to the above), also often rely on cooking at the time of consumption to ensure safety.

Works Cited

E.coli (Escherichia coli). (2017, November 20). Retrieved June 24, 2018, from https://www.cdc.gov/ecoli/ecoli-symptoms.html

(E. coli Risk Profile) https://www.foodsafety.govt.nz/elibrary/industry/Risk_Profile_Shiga-Science_Research.pdf


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