Throwback Thursday: The need to monitor Peracetic Acid in Chicken Processing Plants

While our blog is typically focused on how sterilants are used in the Healthcare market, the need to monitor these chemicals is also seen in other industries. While the situations may look different, the case and reasoning behind monitoring for safety conveys across markets.

Processing aids are used in chicken processing plants to enhance food safety by reducing potential contamination in food during processing. The article referenced here provided a very surface level discussion about these aids. Today we look back to the article, Questions & Answers about Processing Aids Used in Chicken Production, published April 14, 2013, the National Chicken Council (NCC) makes the following statements…

Though antimicrobials are approved for use and are used in very low, allowable concentrations, the poultry industry takes very seriously the health and safety of our workforce and there are a number of steps and precautions in place in order to minimize any exposure to them:

  • When diluted antimicrobials are applied to carcasses, they are done so in controlled areas (inside of closed equipment or inside the chiller) to minimize any potential exposure to employees;
  • In order to ensure proper ventilation, poultry processing plants follows strict guidelines for air flow set by the American Society of Heating, Refrigerating and Air-Conditioning Engineers. Engineering controls such as ventilation are acceptable means to control employee exposure to hazards;
  • Air quality tests are routinely performed in poultry processing plants;
  • Workers and companies must comply with OSHA standards, wear personal protective equipment and complete required training programs;
  • The mixing of water and antimicrobials is a highly automated process in poultry plants so that workers rarely come into contact with any undiluted agents;
  • Most of these antimicrobials have a pungent odor that if an excessive concentration were to occur, it would be taken care of immediately. Therefore, continued exposure to any potential harmful level is very rare.

While we applaud the effort to bring these issues to light, there are some additional facts that should be conveyed and discussed…

Common intervention chemicals, such as Peracetic Acid (PAA), have significant vapor presence at the concentrations typically used.

  • No mention is made of monitoring systems available to ensure exposure levels are known and maintained at safe levels. The ChemDAQ Steri-trac system does just that. The article does mention air quality tests, but it does not go into detail regarding what methodologies are used or the frequency. This could be an entire conversation on its own. There are many ways to go about testing air quality that do not perform the desired outcomes of safety and accuracy.


In our paper “Fallacy of Inferring Lack of Peracetic Acid Vapor from Measurement of Hydrogen Peroxide and Acetic Acid Vapor” we have shown that this approach is not valid. If one wants to measure PAA one needs to monitor for PAA.

  • The NCC article also discusses airflow and ventilation systems. While ventilation systems do help to reduce employee exposure, but it does not guarantee safe levels in the air. Mechanical failures can, and do, happen. The goal is to balance airflow since too much air exchange is expensive, especially in a refrigerated plant, so it is important not to have too much air exchange. Too little air exchange and employees may become overly exposed to hazardous vapors. To make it more difficult, the air ventilation requirements may vary over time, with ambient temperature, line speed, etc. The simplest solution is to use a gas monitor with the output controlling the air handler. This ensures there is enough air exchange to keep people safe, but not too much air exchange.
  • The claim that employees “rarely” come in contact with undiluted agents also does little to allay concerns. Exposure is exposure and there is always the possibility of exposure when working with these chemicals. Even in a diluted state, there are inherent risks that should be managed.
  • Finally, regarding odor, yes, peracetic acid does have a pungent odor, (odor threshold of ~50 ppb). However, our human noses do not come equipped to numerically quantify the concentration levels in the air. Monitors are designed to protect us where nature cannot. The fact of the matter is that the idea that "chemicals can be smelled long before they becomes dangerous" is unreasonable and so is to expect people to determine when concentrations exceed recommended exposure levels.

The conclusion is that in order to protect workers the best, and only true way to be sure is to monitor the air for chemical vapor concentration levels. Worker safety and the use of processing aids was topical in 2013, and is still an issue today.