Hydrogen peroxide is a powerful oxidizing and bleaching agent. It has found various applications in the food industry. Beyond its conventional uses, such as bleaching crude soya lecithin, this versatile chemical also offers antimicrobial properties crucial for preserving cheese milk as well as fresh produce. Additionally, hydrogen peroxide proves effective in sterilizing food processing equipment and packaging material for aseptic food packaging systems.
In this article, we will explore the applications of hydrogen peroxide in the food industry, highlighting its antimicrobial action, decomposition process, and how it contributes to maintaining food safety and quality.
Let’s dive right in.
WHAT IS HYDROGEN PEROXIDE?
Hydrogen peroxide, denoted as H2O2, is a chemical compound consisting of two hydrogen atoms and two oxygen atoms. It exists as a transparent liquid and possesses a mildly bitter flavor. The two hydrogen atoms form a single covalent bond with the two oxygen atoms. Its fragile oxygen-oxygen single bond is highly susceptible to decomposition, often accompanied by the liberation of heat.
The decomposition is also facilitated by light, and the presence of certain catalysts like transition metal ions. The reaction is exothermic, meaning it releases energy.
Hydrogen peroxide exhibits a range of chemical properties, including its ability to decompose into water and oxygen gas. It can readily donate oxygen atoms to other substances, leading to oxidation reactions. This property makes it useful in various applications. It can be used as a bleaching agent, disinfectant, and as an oxygen source in rocket propellants.
You might also like: Guide to Using Chlorine in the Food Industry
In terms of disinfection, hydrogen peroxide does its job by oxidation. The oxygen atoms are highly reactive and can react with various components within the microbial cells. The oxidation process disrupts the structure and function of proteins, DNA, and other cellular components, leading to cell death.
As a bleaching agent, hydrogen peroxide has its ability to break down pigments and colored compounds. It is used in the textile industry for bleaching fabrics and in the paper industry to whiten pulp. However, caution must be exercised as it can also cause bleaching or damage to organic materials.
ANTIMICROBIAL ACTION AND PRESERVATION OF CHEESE
One of the notable uses of hydrogen peroxide in the food industry lies in its antimicrobial action. By leveraging its oxidizing properties, hydrogen peroxide helps inhibit the growth of harmful microorganisms in food products. In the case of cheese production, hydrogen peroxide plays a vital role in preserving cheese milk.
It is possible to add a weak solution of hydrogen peroxide to the cheese milk during the manufacturing process, usually at a concentration of around 0.02%. The Food and Drug Administration (FDA) has set a maximum acceptable treatment amount of hydrogen peroxide in cheese at 0.05%. This concentration efficiently reduces microbial contamination in milk. Any residual hydrogen peroxide after its antibacterial action must be removed. Catalase, an enzyme found in all living creatures, is used to assist the breakdown of hydrogen peroxide into harmless water and oxygen.
The decomposition process of hydrogen peroxide can be accelerated by factors such as increased temperature and the presence of other catalysts such as lacto-peroxidase. This increase in temperature not only promotes the decomposition of hydrogen peroxide, but also enhances its antimicrobial effectiveness. Thus, careful control of the process parameters is essential to ensure both efficient microbial control and the removal of hydrogen peroxide residue to maintain product quality and safety.
The addition of hydrogen peroxide also helps to achieve a softer product with improved moisture retention. In one study, the incorporation of hydrogen peroxide-catalase treatment in the cheese manufacturing process using low-fat milk resulted in a cheddar-like cheese with a softer texture and enhanced moisture retention. This demonstrates its potential application in the production of lower-fat cheeses. Another study has said the enhanced softness may be attributed to the heightened vulnerability of its protein to proteolysis and the increased solubility of H2O2-treated calcium caseinate, particularly during the initial stages of ripening.
CONTROLLING POST-HARVEST DECAY AND EXTENDING SHELF LIFE OF PRODUCE
Hydrogen peroxide solutions have demonstrated effectiveness in various applications, including washing mushrooms, controlling post-harvest decay in vegetables, extending the shelf-life of fresh-cut vegetables and melons, and decontaminating apples with nonpathogenic E. coli. Studies have shown that 5% hydrogen peroxide solutions, either alone or combined with surfactants, can achieve higher reductions in bacterial counts on apples compared to chlorine treatments at 200 ppm. When applied at temperatures from 122°F (50°C) to 140°F (60°C), significant reductions of 3 to 4 log10 CFU/g have been achieved.
In the case of fresh-cut melons, a 5% hydrogen peroxide solution applied before rind removal has proven more effective than chlorine in extending the shelf-life of the melon cubes. Visual observations of spoilage aligned with the microbiological data, indicating that the peroxide treatment suppressed bacterial growth and potentially caused injury to spoilage-causing bacteria.
You might also like: Sanitizing Fresh Fruits and Vegetables Using Chlorine
While hydrogen peroxide vapor treatments can inhibit post-harvest decay in certain commodities, they can be slow and may cause injury to delicate produce such as mushrooms, raspberries, and strawberries. Therefore, alternative methods or lower concentrations may be necessary to ensure the desired effect without harming the produce.
STERILIZATION OF FOOD PROCESSING EQUIPMENTS AND PACKAGING MATERIALS
In food production facilities, ensuring that equipment and surfaces are free from harmful bacteria and other microorganisms is of paramount importance. Hydrogen peroxide’s exceptional antimicrobial properties make it an ideal choice for sterilizing food processing equipment. Research has shown that a powdered form of hydrogen peroxide, available in 3% and 6% solutions, exhibits remarkable efficacy in combating biofilms. Moreover, its effectiveness has been demonstrated in eradicating Listeria monocytogenes when used on latex gloves.
This potent antibacterial agent can be applied to various surfaces, including tanks, pipelines, filling machines, floors, drains, walls, steel mesh gloves, belts, and other areas susceptible to contamination without causing harm. The chemical’s ability to break down into water and oxygen makes it a safe option for use in food processing environments. For this reason, hydrogen peroxide leaves no harmful residue.
You might also like: Unbleached Vs. Bleached flour: The Difference
Another area where hydrogen peroxide proves valuable is in the sterilization of packaging materials. Laminated film packages undergo hydrogen peroxide sterilization before their use. The packaging material is briefly immersed in hot hydrogen peroxide, with the concentration limited to 35%. This method can also be employed for sterilizing film used in the production of cups through thermoforming. After hydrogen peroxide treatment, any remaining residue is eliminated by blowing sterilized air or evaporating it using hot cylinders at 90°C. The process aims to achieve a hydrogen peroxide residue level below 0.05 ppm. Sterilization of the packaging material typically takes approximately 10 minutes, including a 5-minute period for reaching the evaporation temperature.
BLEACHING OF SOYA LECITHIN
Hydrogen peroxide finds utility as a bleaching agent as well. However, its application in this context is more targeted and subject to stricter regulations compared to other sectors. When employed as a bleaching agent in food, hydrogen peroxide is primarily directed towards certain food ingredients and additives, rather than being utilized for enhancing the overall appearance of the food product.
The concentration and application of hydrogen peroxide must be carefully controlled to prevent any potential adverse effects on the taste, quality, or safety. One common application of hydrogen peroxide as a bleaching agent is for the bleaching of crude soya lecithin. Soya lecithin is a natural emulsifier and food ingredient derived from soybeans. The crude form of soya lecithin has a yellowish color due to the presence of impurities.
Hydrogen peroxide can be used to bleach and remove these impurities. This results in a lighter, more desirable color for the final product. Single-bleached products are prepared by adding 0.3 to 1.5% of 30% hydrogen peroxide directly to the gums. For double-bleached lecithin, benzoyl peroxide is used in conjunction with hydrogen peroxide, either during the bleaching process or added to the dried gums.
References:
N. Marriott, R. Gravani (2007). Principles of Food Sanitation (5th edition). Springer
G. Saravacos, A. Kostaropoulos (2016). Handbook of Food Processing Equipment (2nd edition). Springer
Y. Motarjemi, H. Lelieveld (2014). Food Safety Management: A Practical Guide For The Food Industry. Academic Press.
J. deMan, J. Finley, W. Jeffrey Hurst, C. Y. Lee (2018). Principles of Food Chemistry (4th edition). Springer.
P. Walstra. J. Wouters, T. Geurts (2006). Dairy Science and Technology (2nd edition). CRC Press.
