There are many sanitizers that you can use to keep your produce or working environment safe from harmful microorganisms like bacteria and viruses. But if I were to pick one which to use, I’d definitely go with chlorine, like most companies do. This is because not only it one of the most effective, but it is also the most economical as well. And its versatility is just a bonus to that. You can use chlorine to sanitize food products, food contact surfaces, equipment, and the food processing area. However, there are many key points that one must keep in mind when handling chlorine.
Read this guide to using chlorine in the food industry.
Table of Contents
Why use chlorine?
- Economical
- Effective in reducing harmful microorganisms to a safer level
- Products are more attractive to customers
- Products have longer shelf life
- Processing area is more hygienic
How exactly chlorine kill microorganisms?
Chlorine usually comes in the form of granules or in liquid solutions, which you can dilute in water according to the concentration you need. When added to water of certain concentration, it can kill a wide range of microorganisms like bacteria, viruses, fungi and parasites. Chlorine does this by releasing hypochlorous, an acid that can destroy the proteins inside the microorganism’s cells.
Chlorine as part of food washing?
It might sound strange and dangerous, but chlorine has been used for decades in the food industry to wash food items As part of post harvest handling, chlorine (sodium hypochlorite) is used for washing fruits and vegetables. This practice has been long proven to be totally safe and highly effective in preventing transmission of microorganisms, particularly pathogens.
At safe levels of concentration, chlorinated water is also used to wash chicken through the use of rinsers and sprayers in many dressing plants. This practice isn’t as common in the United States anymore as it is in other countries though.
Factors that affect effectiveness of chlorine
With the correct concentration, chlorine is one of the most effective sanitizers to eliminate undesirable microorganisms. Weak concentration may not be effective, and too strong concentration is toxic and corrosive. However, the efficacy of chlorine is not only limited to its concentration. Temperature, presence of organic matter, pH, contact time, to name a few, also dictate how effective chlorine is.
Temperature
Usually, warmer temperature increases the effectively of chlorine. This is the reason why most processes heat chlorinated water at around 120°F (49°C) to 200°F (93°C). Furthermore, higher temperature also helps in removing residual chlorine.
You might also like: How To Calibrate A Food Thermometer
Presence of organic matter
The present of organic matter is more inevitable in most meat processing plants. After every production day, there would be plenty to remove, usually fats and grease, to prepare for the next day. Removing excess dirt, fats, grease and other organic matter first before applying chlorine enhances sanitation effectiveness.
pH level
Chlorine solution effectiveness is highly dictated by its pH level. pH near neutral (around 6.0 to 7.0) is best for sanitation. Anywhere in the alkaline level decreases its effectiveness. When using alkaline –based cleaner, make sure the area is thoroughly washed to remove any excess of the cleaner. Furthermore, pH below 6.0 is more corrosive and may emit harmful chlorine fumes.
Contact time
Most sanitizers require contact time of anywhere from half a minute up to 15 minutes. For chlorine, it would only take around 1 to 5 minutes to neutralize microbial activity. Of course, the higher the concentration, the faster it will take effect. Be wary though, as if left longer than required, chlorine solutions can corrode equipments faster.
Other factors
There are certain products like vegetables that have higher surface area and uneven surfaces. Applying chlorine to such may not be effective. If this is the case, surfactant can solve this by lowering the surface tension.
Most commercially available chlorine (bleaches) intended for household use may contain additives like thickeners and scents and therefore not classified as food grade. Chlorine for making sanitizing solution must be pure in order to be classified as food grade material.
Preparation of chlorine concentration
As a general rule, you can apply chlorine solution of 50 ppm (parts per million) up to 200 ppm to products for washing and food contact surfaces like tables, chutes and other processing equipment. The 200 ppm is the maximum allowable strength as per Code of Federal Regulations Title 21 Part 178 of US FDA.
Most sodium hypochlorite for household use is 5% chlorine. For industrial use, sodium hypochlorite trade strength comes at around 12% to 15%.
Computation
Say for example you want to prepare 100 liters of chlorine solution with strength of 200 ppm from an industrial 12.5% hypochlorite (NaOCI). You want to know much hypochlorine solution (by volume) you need to add to your working solution.
First, define your numbers to work with.
| Initial chlorine concentration | 125,000 ppm (converted) |
| Initial chlorine volume to add | ? |
| Final chlorine volume desired | 100,000 ml (converted) |
| Final chlorine volume concentration | 200 ppm |
Do the formula.
Initial chlorine concentration * Initial chlorine volume to add (?) = final chlorine volume desired * final chlorine solution concentration desired
So to prepare 100 liters of 200 ppm chlorine concentration, you need to add 160 ml of 12.5 % hypochlorite (NaOCI) with warm water. Once your 200 ppm chlorine solution is ready, you can further dilute it accordingly, depending on its intended use.
Use the above formula according to your need.
Checking the level of chlorine
You may have prepared your chlorine solution well, but the only way to be certain is checking it’s strength. And over time, the strength of chlorine solution weakens as you use it. It is necessary to check it at regular intervals to ensure its effectiveness. Using test kits or test strips, you can determine the active chlorine level and the pH.
Nowadays, it is easy to find stores online that sell test kits or test strips. Just make sure the legitimacy. But I suggest obtaining one directly from suppliers.
In choosing test kits or test strips, you would want one that mainly measure the free chlorine available instead of the total chlorine.
Free chlorine is the amount of chlorine that is ready to neutralize contaminants like microorganisms while the total chlorine includes both free chlorine and combine chlorine, the chlorine that already interacted with contaminants and is considered no longer useful.
Checking the concentration commonly involves color change in the sample solution according to its concentration level and this result is compared using a chart or color meter that comes with the test kits or test strips.
Remember, when purchasing test kits or test strips, make sure they can do your requirement because there are some that can only read 100 ppm maximum.
I hope you find this Guide to Using Chlorine in the Food Industry article helpful.
