The L. Monocytogenes has a lower pathogenic potential than other food borne pathogens. Therefore, the number of pathogens ingested through foods is still low. It is however inconsistent with the relatively high 50% lethal dose (LD50) (Lee 98). Therefore, the minimum dose required for causing clinical infection in the humans is yet to be determined but the large numbers of the L. Monocytogenes bacteria detected in the foods responsible for sporadic and epidemic listeriosis cases suggests it is still high
The vibrio cholera, the cholera agent, is a normal inhabitant of the aquatic environment. It survives under a wide range of salinity and pH. The effect of selected environmental parameters can be identified through chemically defined solutions. From such conditions, the growth and activity of the vibrio cholera are seen as being affected and influenced by the low pH. The low pH was responsible for the reduced effectiveness and growth of the vibrio cholera bacteria. This condition of the pH altered the internal process of the bacteria causing it to slow down and reproduce slowly. Low pH contained less Na+ that was relevant for the growth of the bacteria. Hence, the vibrio cholera bacteria were bound to be minimal in number. From a past study by (Vimont, 1-4), vibrio cholera can be cultured for a period of 4days using and estuarine salinity of 25%. Salinity of the bacteria’s niche influenced the activity as measured through the uptake of 14C –amino acids. From the study of selected ions, it was evident that the activity and growth of the cholera were affected by pH.
The LD50 is the dose at which a drug becomes lethal for 50% of the target population. It is expressed as the mass of the bacteria administered per mass of the target. Different bacteria types impact on the host differently. The lethal dose for particular bacteria can change over time due to various factors. This can be affected by the toxicity and the amount of the bacteria cells. As the