The effects of PH on bacterial growth
Image by Flickr.com, courtesy of Umberto Salvagnin
Bacteria are one of the most enduring and oldest kind of living organisms on earth. Although bacteria can cause disease, they are also essential for life. One way of affecting the growth of bacteria is by changing its pH level. Bacteria, like all living organisms, prefer a certain pH balance.
Over millions of years, some bacteria have developed mechanisms to adapt to pH imbalances.
All bacteria require a certain pH level, which can vary widely in the many different types of bacteria, reports Trudy Wassenaar of Argonne National Laboratory. Changing the pH level means adding or subtracting hydrogen ions. Whether bacteria can live outside of their optimal pH range depends on the particular bacteria's ability to live in or self-correct environmental pH changes.
Changes in pH levels have the most noticeable effects on bacterial enzymes, reports Argonne National Laboratory. Extreme changes in the pH balance of the local environment for bacteria tend to kill them, but one common bacteria, Helicobacter Pylori, can handle highly acidic environments like the human stomach. In the stomach, Helicobacter Pylori create a shell of urease to protect themselves from stomach acid.
Whether pH has an inhibitory or positive effect on bacterial growth depends on the if the bacteria is an acidophile, neutralphile or alkiphile, reports Griffith University. An acidophile grows in a pH range of 1 to 5.9, a neutralphile between 6.0 and 9.0 and a alkiphile between 9 and 11.
Knowing the effects that pH has on bacteria is essential for those in the food inspection sector, according to Integrated Publishing. Bacteria has a hard time growing in fruits, which are often highly acidic, and vegetables, which contain too much alkaline. Meats have a neutral pH and are much more likely to develop illness causing bacteria, and thus need stricter food preparation requirements.
Although raising the pH level of bacteria may kill them, this does not necessarily result in preventing bacteria from growing in any particular environment, reports Argonne National Laboratory. Changing the pH level to eliminate one species of bacteria may give rise to another species that can live in the new pH level.
- Image by Flickr.com, courtesy of Umberto Salvagnin