Question

The hospital and the local health department have identified a single brand of ice cream that all four of the patients consumed within the last few days. part of your job is to determine whether the ice cream could support the growth of the bacterial contaminant. you know that the ice cream is high in sugar and other organic compounds, so the bacteria would have the nutrients required for cellular metabolism; however, the ice cream is produced and maintained at low temperatures and stored at freezing or below freezing temperatures. can bacteria or any organisms grow at these extremely low temperatures? when introduced into a new niche, bacteria may evolve by altering their proteins and cellular membranes to adapt to the new temperature. environmental temperatures are nothing more than available heat, which for a cell system is the addition (hot temperatures) or removal (cold temperatures) of outside energy to an enzymatic reaction. as temperatures increase, the addition of energy will speed up enzymatic reactions until the point at which the additional heat energy begins to interfere with the hydrogen bonds holding the protein structure of the enzyme together. once the enzyme loses its structure, all activity is lost. the same will occur with the lipid bilayer that forms the cell's membrane: increased movement of the phospholipids will result in leakage out of the cell. at the opposite end of the temperature spectrum, reduced temperatures slow down enzyme activity and lipid movement in the membrane. the question you are stuck with is whether or not there are any bacterial pathogens that can grow in such cold temperatures.

Answer 1

Psychophiles are bacteria can grow and survive in really low temperatures. These organism are adapted to freezing temperatures by producing antifreeze proteins that protect the organisms from vetrification and dessication. Examples of psychophilic bacteria that can contaminate food include Aeromonas spp and Yersinia spp