Cover

Contents

Contributors

1 Status and Trends of Ozone in Food Processing

1.1 Why ozone?

1.2 Drivers of ozone in the food industry

1.3 The hurdle concept

1.4 Challenges

1.5 Objective

2 Regulatory and Legislative Issues

2.1 Introduction

2.2 History of ozone application and regulation

2.3 Ozone regulation

2.4 Global harmonisation of food safety regulations

3 Chemical and Physical Properties of Ozone

3.1 Introduction

3.2 The molecular structure of ozone

3.3 The chemical and physical properties of ozone

3.4 Ozone action on macromolecules

3.5 Mechanisms of microbial inactivation

3.6 Ozone reactions against virus

3.7 Ozone reaction on biofilms

4 Generation and Control of Ozone

4.1 Introduction

4.2 Ozone generation

4.4 Solubility of ozone in water

4.5 Contacting ozone with water: physical means of transferring ozone into water

4.6 Measuring and monitoring ozone in water

4.7 Measuring and monitoring ozone in air

4.8 Ozonation equipment for food storage rooms

4.9 Ozone generator output control

4.10 Some recent novel applications for ozone generation in food processing plants

4.11 Helpful calculations

5 Ozone in Fruit and Vegetable Processing

5.1 Introduction

5.2 Applications in fruit and vegetable processing

5.3 Efficacy of ozone

5.4 Synergistic effects with ozone

5.5 Effect of ozone on product quality and nutrition

5.6 Conclusion

6 Ozone in Grain Processing

6.1 Introduction

6.2 Ozone application in grain storage and effects on grain components

6.3 Effects of ozone on grain processing, flour and product quality

6.4 Industrial applications and scale-up

6.5 Conclusions

7 Ozonation of Hydrocolloids

7.1 Introduction

7.2 Application of ozone in hydrocolloid processing

7.3 Effects of ozone on the physiochemical properties of hydrocolloids

7.4 Mechanism and structural effects of ozone action on hydrocolloids

8 Ozone in Meat Processing

8.1 Introduction

8.2 Application of ozone in meat processing

8.3 Effect on meat quality

9 Ozone in Seafood Processing

9.1 Introduction

9.2 Application of ozone in fish and storage of processed seafood products

9.3 Application of ozone in seafood plant sanitation

9.4 Effects of ozone on microbial safety

9.5 Effects of ozone on fish and seafood quality and shelf life

9.6 Current status and future trends for ozone and seafood

10 Ozone Sanitisation in the Food Industry

10.1 Introduction

10.2 Ozone as a sanitising agent

10.3 Health and safety issues

10.4 Using ozone in industrial cleaning procedures

10.5 Ozone applications in food processing

11 Ozone for Water Treatment and its Potential for Process Water Reuse in the Food Industry

Nomenclature

11.1 Introduction

11.2 Water in the food industry

11.3 Ozonation as a water treatment process

11.4 The kinetics of ozonation

11.5 Conclusion

12 Ozone for Food Waste and Odour Treatment

12.1 Introduction

12.2 Application of ozonation to waste treatment

12.3 Application of ozonation to odour removal

12.4 Conclusions

13 Efficacy of Ozone on Pesticide Residues

13.1 Introduction

13.2 Types of pesticides

13.3 Fates of pesticides

13.4 Degradation mechanisms

13.5 Ozone application for pesticide residues in fruits and vegetables

13.6 Current status and opportunities

14 Modelling Approaches for Ozone Processing

Nomenclature

14.1 Introduction

14.2 Modelling approaches for microbial inactivation

14.3 Chemical reaction kinetics

14.4 Modelling ozonation processes

14.5 Conclusions

15 Health and Safety Aspects of Ozone Processing

15.1 Introduction

15.2 Points of application of ozone during food processing

15.3 Health and safety issues with ozone for food plant workers

15.4 Avoiding worker exposure to ozone in food processing plants

15.5 Safety of foods processed with ozone

5.6 Conclusions

Index

Advertisements

Plates

Image

Contributors

Hee-Jung An

Department of Food Science, Louisiana State University Agricultural Center, 111 Food Science Building, Louisiana State University, Baton Rouge, LA, USA

Ioannis S. Arvanitoyannis
Department of Agriculture Crop and Animal Production, Ichthyology and Aquatic Environment, School of Agricultural Sciences, University of Thessaly, Volos, Greece

Gilbert Y.S. Chan
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

P.J. Cullen
School of Food Science & Environmental Health, Dublin Institute of Technology, Dublin, Ireland

Annel K. Greene
Department of Animal and Veterinary Sciences, Clemson University, Clemson, SC, USA

Zeynep B. Güzel-Seydim
Food Science and Human Nutrition, Clemson University, Clemson, SC, USA

Joan M. King
Department of Food Science, Louisiana State University Agricultural Center, Louisiana State University, Baton Rouge, LA, USA

Paula Misiewicz
Engineering Department, Harper Adams University College, Newport, Shropshire, UK

K. Muthukumarappan
Agricultural and Biosystems Engineering Department, South Dakota State University, Brookings, SD, USA

Shigezou Naito
Department of Nutrition and Food Science, Aichi Gakusen College, Aichi, Japan

Tomás Norton
Engineering Department, Harper Adams University College, Newport, Shropshire, UK

Colm O’Donnell
School of Biosystems Engineering, University College Dublin, Dublin, Ireland

V. Lullien-Pellerin
INRA, UMR 1208 Ingénierie des Agropolymères et Technologies Emergentes, Montpellier, France

Fred W. Pohlman
Department of Animal Science, University of Arkansas, Fayetteville, AR, USA

Alfredo Prudente
Rutgers The State University, Department of Food Science, New Brunswick, NJ, USA

Rip G. Rice
RICE International Consulting Enterprise, Sandy Spring, MD, USA

Seung-wook Seo
Nongshim, 203-1, DangJeong-Dong, Gunpo-SiGyeonggi-Do, Korea

Atıf Can Seydim
Department of Food Engineering, Faculty of Engineering, Süleyman Demirel University, Isparta, Turkey

Cameron Tapp
Clearwater Tech, San Luis Obispo, CA, USA

B.K. Tiwari
Manchester Food Research Centre, Hollings Faculty, Manchester Metropolitan University, Manchester, UK

Vasilis P. Valdramidis
Department of Food Science, Louisiana State University Agricultural Center, Louisiana State University, Baton Rouge, LA, USA

J.G. Wu
Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong

1

Status and Trends of Ozone in Food Processing

Colm O’Donnell, B.K. Tiwari, P.J. Cullen and Rip G. Rice

1.1 Why ozone?

Interest in ozone has expanded in recent years in response to consumer demands for ‘greener’ food additives, regulatory approval and the increasing acceptance that ozone is an environmentally friendly technology. The multifunctionality of ozone makes it a promising food processing agent. Excess ozone autodecomposes rapidly to produce oxygen and thus leaves no residues in foods from its decomposition. In particular, the US Food and Drug Administration (FDA)’s rulings on ozone usage in food have resulted in increased interest in potential food applications worldwide. Ozone as an oxidant is used in water treatment, sanitising, washing and disinfection of equipment, odour removal, and fruit, vegetable, meat and seafood processing.

1.2 Drivers of ozone in the food industry

1.2.1 Regulation

While food safety assurance is a global concern, approaches to regulation differ throughout the world. Globally the regulatory status of ozone for food processing applications is still in an evolving state of flux, and in some countries has not been addressed to date. Legislation governing ozonation for treating, handling, processing and storage of foods has typically developed in response to the evolving use of ozone from initial applications for water treatment, through surface and equipment cleaning, food produce washes, and finally to use as a direct food additive. The use of ozone in food processing has become increasingly important as a result of the affirmation of ozone as a GRAS (Generally Recognised as Safe) chemical in 1997 (Graham et al. 1997) and its subsequent approval by the US FDA as an antimicrobial additive for direct contact with foods of all types (FDA 2001). The use of ozone in food processing has been approved to various degrees in many countries, including the USA, Japan, Australia, France and Canada. Given the complexities of food matrices and the range of foods produced, demonstrating process validation is a challenge for industry. However, more expedited validation processes are likely with validation of comparable products.

1.2.2 Surface cleaning and disinfection

The need to develop nonresidual and validated cleaning approaches for the food industry has been clearly indentified. Ozone offers the food industry an alternative or complementary cleaning and sanitising agent. The efficacy of ozone for physical, chemical and biological cleaning within food processing units has been reported. The potential inclusion of ozone-containing water within the clean-in-place (CIP) cycle offers significant opportunities for food processors. Comparisons of treatment efficacy against traditional approaches are discussed in Chapter 10. Applications of ozone for sanitising various food processing equipment items are reviewed. The use of ozone for cleaning within comparable process industries, such as pharmaceuticals, is also outlined.

1.2.3 Food safety and shelf life extension

Food treatment approaches include ozone applications in both the gaseous and aqueous phases. Washes in ozone-containing water, storage in ozone-rich atmospheres and direct addition of ozone in fluid foods are reviewed. The antimicrobial efficacies of ozone for control of pathogenic microorganisms of concern in the food industry are reviewed in Chapter 3. The effectiveness of ozone against microorganisms present in food systems depends on several factors including the amount of ozone applied, the residual ozone in the medium and various environmental factors such as medium pH, temperature, relative humidity, additives and the amount of organic matter surrounding the cells.

Storage grains are susceptible to a number of insects, which cause considerable damage to the stored grains and could potentially develop resistance to the currently employed insecticides. Increasing environmental problems and new legislation have tended to reduce the permitted pesticide amounts or even prohibited their use. Ozone use in fumigation is an alternative to chemicals in controlling insect development. The use of ozone for the control of fungi and mycotoxins in grains is discussed in Chapter 6.

The potential of ozone for the degradation of pesticide residues found in food is discussed in Chapter 13. The proposed mechanisms for degradation of pesticides, including organophosphates and organochlorinated compounds, are outlined. The efficacy of both gaseous and aqueous ozone for degradation and the processing parameters governing the process are reviewed.

1.2.4 Nutrient and sensory aspects

Taste and sensory properties are consistently rated as the most important factors driving consumption and repeat purchase of food products. The principal driver for industrial adoption of new processing technology is to meet consumers’ demands for improved taste and nutrition. Ozone is a strong oxidising agent and its effect on such parameters must be considered prior to any potential food application. Effects will be dependent upon the mode of application, the dose, food composition and so on. Each application chapter discusses the reported effects on such parameters.

1.2.5 Consumer and processor acceptability

Consumers are not only concerned about the ingredients within the foods they consume, but also about the processes that are employed in bringing food ‘from farm to fork’. A growing body of consumer research suggests that consumers are increasingly conscious of the food supply chain, which will continue to influence their perceptions of emerging food processes. Paradoxically, consumers are demanding foods which are minimally processed, meet their nutritional and taste desires yet require minimal preparation. Understanding and addressing consumer issues related to any novel food process are some of the most important challenges facing the developers of innovative food products. Research suggests that acceptance of new technologies is based to a great extent on public perceptions of the associated risks, and that perceptions of risk are influenced by trust in information and the source that provides it (Frewer et al. 2003). Several consumer research studies have consistently shown that consumers have poor knowledge and awareness levels towards most novel food processing techniques, which serves as a major impediment to their acceptance. Thus, effective communication regarding details of the technologies and their benefits becomes essential for successful marketing of these products. If a novel technology allows the introduction of new products with tangible benefits, consumers are most likely to accept it.

For the processor, it is critical that any process adopted is safe for the production staff. Chapter 15 reviews the precautions dealing with the release of gaseous ozone in amounts that might cause discomfort or injury to plant workers. The health and safety issues associated with ozone are reviewed, followed by a discussion of the commonly accepted worker safety regulations for breathing gas-phase ozone.

1.2.6 Technology advances

There have been significant developments in the methodologies of ozone production, including corona discharge/plasma and UV radiation, which make ozonation a more attractive approach for food processing. Economic and technical aspects of ozone production are outlined in Chapter 4, including process controls, production scales, application approaches and the limitations of each procedure. Challenges encountered in the industrial production of ozone are addressed, along with future trends. Novel systems for generation of ozone within sealed packages under air or modified atmospheres are described. Such approaches are suitable for many food applications, from fresh produce to meat products.

1.2.7 Environmental impact

To achieve the full potential of commercial exploitation of novel technologies, issues related to environmental impacts, such as wastewater and gas emissions, the conservation of nonrenewable resources and energy consumption, must be investigated and understood by food processors, since they can represent significant potential reductions in processing costs (Pereira and Vicente 2010). The food industry is a significant consumer of energy, with the principal type of energy used for traditional thermal processing being fossil fuel. Water is a key ingredient in the food industry, playing a fundamental role in many of the common food processing methods and unit operations, such as soaking, washing, rinsing, blanching, heating, pasteurising, chilling, cooling and steam production, acting as an ingredient, and being used for general cleaning, sanitation and disinfection purposes. However, the industry is not so well known for its use of water-saving devices and practices. While ozone has been a globally successful water treatment method, the literature has shown that it has not been largely employed as yet by the food industry, even though it was approved for application in the reconditioning of recycled poultry chilling water by the US Department of Agriculture in 1997 (Güzel-Seydim et al. 2004). Chapter 11 discusses the potentials of ozone as an alternative for potable water treatment, wastewater treatment and water reuse in the food industry. Applications are identified in the fruit and vegetable, meat and dairy sectors. The efficacy of ozone for physically, chemically and microbiologically safe reuse of water in the food industry is discussed.

1.3 The hurdle concept

Combining a number of preservation methods may enhance the overall antimicrobial effect so that lower process intensities can be employed. This approach, known as ‘hurdle technology’, has already been applied successfully using traditional techniques of food preservation (Leistner and Gorris 1995). Combining ozone methods with other food preservation techniques can (1) enhance the lethal effects, (2) reduce the severity of treatment required to obtain a given level of microbial inactivation and (3) prevent the proliferation of survivors following treatment. The choice of hurdles – several combinations of either novel thermal, novel nonthermal or conventional processing technologies – is generally made to maximise the synergistic effect on the microbial inactivation kinetics. Food preservation using combined methods involves successive or simultaneous applications of various individual treatments. Combined treatments are advantageous, principally because many individual treatments alone are not adequate to ensure food safety or stability.

1.4 Challenges

Despite significant scientific advances and the demonstrated industrial potential of ozone in seafood, meat and decontamination of pesticide residues in the food chain, there is a paucity of reported studies in this area in general. Also, the potential for reduced processing costs through the use of ozone technologies has not been widely disseminated. Awareness and understanding of ozone applications for foods is key to improved uptake of ozone technology by industry. Increased clarity of the regulatory status of ozone for food applications would facilitate increased global adoption by the food industry.

1.5 Objective

The objective of this book is to demonstrate the potential technoeconomic benefits of employing ozone in the food industry to facilitate increased industry adoption. This book provides an insight into the current state of the art and reviews emerging applications of ozone processing. The principles of ozonation, process control parameters, microbial inactivation mechanisms and the effects on food nutritional and quality parameters are outlined. Separate chapters are dedicated to covering different food processing applications. Finally, health and safety aspects of ozone as used in food processing plants and future trends in industry adoption of ozonation are discussed.

References

FDA (2001) Hazard analysis and critical control point (HACCP): procedures for the safe and sanitary processing and importing of juice; final rule, Federal Register, 66: 6137–6202.

Frewer, L., Scholderer, J. and Lambert, N. (2003) Consumer acceptance of functional foods: issues for the future, British Food Journal, 105: 714–31.

Graham, D.M., Pariza, M.W., Glaze, W.H., Erdman, J.W., Newell, G.W. and Borzelleca, J.F. (1997) Use of ozone for food processing, Food Technology, 51(6): 72–6.

Güzel-Seydim, Z.B., Greene, A.K. and Seydim, A.C. (2004) Use of ozone in the food industry, Lebensm.-Wiss. Technol.-Food Sci. Technol., 37(4): 453–460.

Leistner, L. and Gorris, G.M. (1995) Food preservation by hurdle technology, Trends in Food Science and Technology, 6: 41–46.

Pereira, R.N. and Vicente, A.A. (2010) Environmental impact of novel thermal and non-thermal technologies in food processing, Food Research International, 43: 1936–43.

2

Regulatory and Legislative Issues

B.K. Tiwari and Rip G. Rice

2.1 Introduction

Ozone has been used commercially for the treatment of drinking water since 1906 Nice, France (Hill and Rice 1982) and is increasingly employed in the food industry for produce preservation and sanitising of food-contact surfaces. Demand for new preservation approaches arises from growing consumer preference for minimally processed foods, frequent outbreaks of food-related illnesses, identification of new food pathogens and the passage of legislation governing food quality and safety. The World Health Organization (WHO) identified foodborne diseases as a considerable threat to human health and the global economy which requires a concerted effort on the part of three principal partners, namely governments, the food industry and consumers. For sanitising applications, ozone may be preferred over traditional sanitisers such as chlorine because of the relatively low inactivation rate of chlorine at concentrations which are limited by regulation, combined with consumer concerns over chemical residues and potential environmental impacts.

The legislation governing ozonation typically has been developed in response to the evolving use of ozone, from initial applications for water treatment, through surface and equipment cleaning, to food produce washes and more recently as a direct food additive. It is likely that the introduction of legislation governing ozonation applications in food processing will encourage the adoption of ozonation processes in industry. However, globally the regulatory status of ozone for food processing applications is still in an evolving state, and in some countries it has not yet been addressed. Food processors who wish to employ ozonation in their plants should consult with their regulatory agencies to ascertain what regulatory constraints, if any, exist that impact on their proposed process or product involving the use of ozone. This chapter outlines the current legislative and regulatory status of ozone for food processing applications where it has been developed.

2.2 History of ozone application and regulation

Ozone was first discovered in 1839 by Schönbein, who observed that the electrolysis of water produced an odorous gas. Table 2.1 shows a brief history of ozone application and regulation. Ozone was first used commercially as a disinfectant of drinking water in France early in the 1900s (Hill and Rice 1982). Currently there are an estimated several thousand drinking water treatment plants in the world using ozone (authors’ estimate based on industry contacts).

Table 2.1 History of ozone application and regulation.

YearAchievements
1839Discovery of ozone by Schönbein.
1895The molecular formula of ozone determined by Soret.
1886The potential of ozone to disinfect polluted water recognised in Europe.
1891Test results from Germany show that ozone is effective against bacteria.
1893First full-scale application using ozone for drinking water in the Netherlands.
1906France commissions its first municipal ozone plant for drinking water.
1909Ozone employed for preservation of meat in Germany.
1914Research leads to the production of inexpensive chlorine gas and interest in ozone for water treatment begins to decline.
1936Ozone used to depurate shellfish in France.
1939Ozone found to prevent the growth of yeast and mould during the storage of fruits.
1942Ozone used in egg-storage rooms and in cheese-storage facilities in the USA.
1957Ozone implemented for oxidation of iron and manganese in German drinking water.
1964Spontaneous flocculation in ozone contact chambers leads to France constructing an ozone plant to enhance particulate removal.
1965Ozone employed for colour control of surface water in Ireland and the UK. Ozone used to oxidize micropollutants such as phenolic compounds and several pesticides in Switzerland.
1970Ozone exploited for algae control in France.
1982US FDA grants GRAS (generally recognised as safe) status for ozone disinfection of bottled water.
1987600 MGD (million gallons per day) ozonation plant comes on line in Los Angeles after seven years of pilot testing.
1995FDA GRAS approval for ozone disinfection of bottled water renewed.
1997Expert Panel convened by the Electric Power Research Institute (EPRI) affirms ozone as GRAS for direct contact with foods. FDA does not object to this GRAS affirmation. Regulators have the option to later add controls on ozone use.
1999United States Department of Agriculture (USDA) rejects an ozone protocol for meat application, citing the 1982 GRAS declaration for disinfection of bottled water in which the FDA stated ‘any other use must be regulated by a Food Additive Petition’.
2000A Food Additive Petition (FAP) filed by the EPRI requests FDA approval of ozone for direct contact with foods.
2001FDA approves ozone as a secondary direct food additive, antimicrobial agent (Federal Register, Vol. 66, no. 123, June 26).
The American Meat Institute files a letter with the US FSIS (Food Safety and Inspection Service of the FDA) asking for an interpretation on the scope of FDA rule. In its response, FSIS determines that, ‘The use of ozone on meat and poultry products, including treatment of ready-to-eat meat and poultry products just prior to packaging, is acceptable’, and that there are ‘no labelling issues in regard to treated product’.
2004FDA issues industrial guidance and recommendations to processors of apple juice or cider on the use of ozone for pathogen reduction purposes.

2.3 Ozone regulation

2.3.1 Overview of US regulations

Although ozone and its oxidising properties were first discovered as early as 1840, application of ozone was relatively recent in the USA. Ozone is approved by the US Food and Drug Administration (FDA) for use in the USA and has been employed successfully for applications including surface decontamination to extend the shelf life of cheeses and fresh produce, decontamination of packaging materials, disinfection of process water and sanitisation of processing equipment and food storage areas, among other things (Mahapatra et al. 2005).

Ozone is Generally Recognised as Safe (GRAS) in the USA for disinfection of bottled water and as a sanitiser for process trains in bottled water plants (FDA 1995). In 1997, ozone was affirmed as having GRAS status for direct contact with foods by an independent panel of experts, sponsored by the Electric Power Research Institute (EPRI) (Graham et al. 1997). The FDA released a final ruling in June 2001, in response to an EPRI food additive petition, amending previous food additive regulations and granting regulatory approval of ozone as an antimicrobial agent for direct contact with foods (FDA 2001). An antimicrobial agent is defined as an agent that will provide 2 log reductions in microbial levels. The amendment to the FDA’s food additive regulations (Title 21 of the Code of Federal Regulations, part 173) allows the use of ozone when used as a gas or dissolved in water as an antimicrobial agent for food. This federal ruling cleared the way for the potential use of ozone in the US food processing industry (Hampson 2001). Ozone is also approved in the USA for use on all meat and poultry products by the US Department of Agriculture (USDA FSIS 2001) when applied in accordance with current industry standards of good manufacturing practice (21 CFR 173.368; FDA 2003).

Enforcement of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA) is under the administrative jurisdiction of the US Environmental Protection Agency (EPA). The provisions of the FIFRA are written to regulate the use of chemicals that are applied as insecticides, fungicides and/or rodenticides. Under the FIFRA, ‘chemicals’ are defined as materials that are manufactured, packaged, transported, stored and applied. Because of the characteristics of ozone (an unstable gas that must be generated and used on site as it is needed), it cannot be packaged, stored or shipped from a manufacturing point miles away from its point of use. Therefore, neither ozone nor ultraviolet (UV) radiation can be regulated as a chemical under the FIFRA. However, a provision was included in the FIFRA whereby manufacturers of ozone- and UV-generating machines are required to register these generators as ‘devices’ that are manufactured, sold and/or used in the USA. The intent of this FIFRA provision is to provide the EPA with a register of (ozone and UV) generator manufacturers. In exchange for registering their products and for agreeing not to make claims for products (ozone and UV) that are not supported by the technical literature, (ozone and UV) generator manufacturers are issued a special EPA Establishment Registration decal that must be mounted on each generator. The decal simply states that the manufacturer of the labelled (ozone or UV) generator has registered his/her manufacturing facility with the EPA. The fact that an ozone or UV generator carries an EPA Establishment Registration Label does not in any way denote approval of ozone by the EPA for any application. On the other hand, if an EPA inspector visits a food processing plant and find that an (ozone or UV) generating device does not carry an EPA Establishment Registration Label, that inspector has the authority to order the unlabeled device to be taken off line. Therefore, any food processor using ozone within the USA should ensure that whoever supplies their facility with ozone generation equipment has registered that product with the EPA as a device under the FIFRA. Non-US manufacturers of ozone (or UV) generators supplying those devices inside the USA are subject to the device registration requirements of the FIFRA. From the worker safety point of view, processors must also ensure that plant workers are not exposed to concentrations of ozone higher than: (1) 0.1 ppm by volume (0.2 mg/m3 NTP) on a time-weighted average over an 8 h/d basis and (2) 0.3 ppm by volume (0.6 mg/m3 NTP) as a limit for a maximum exposure time of 15 minutes, not to be exceeded more than four times daily, according to US Occupational Safety and Health Administration (OSHA) regulations (please see Chapter 14) (CFR 1997).

Ozonation of fresh produce

The definition of the product used to disinfect washwater depends on the type of product to be washed, and in some cases on the location where the disinfectant is used (IFPA 2001). In the USA, the washwater disinfectants used for fresh-cut produce are regulated by the FDA as secondary direct food additives, unless they have been affirmed to be GRAS. Where a raw agricultural commodity is washed in a food processing facility, such as a fresh-cut facility, both the EPA and the FDA have regulatory jurisdiction, and the disinfecting agents (except for ozone and UV radiation) must be registered as pesticides with the EPA.

Ozonation of apple cider/juice

Several incidents of foodborne disease have been associated with juices. In 1991, an outbreak of Escherichia coli O157:H7 infections and haemolytic uremic syndrome was linked to traditionally pressed apple cider. In the USA 21 juice-associated outbreaks were reported to the Centers for Disease Control and Prevention (CDC) between 1995 and 2005 (Vojdani et al. 2008). E. coli O157:H7 is an enteric pathogen with a low infectious dose, which usually causes hemorrhagic colitis but also has the potential to cause haemolytic uremic syndrome in young children and the immunocompromised (Boyce et al. 1995).

These outbreaks led the FDA to issue hazard analysis and critical control point (HACCP) regulations for safe and sanitary processing of juice (FDA 2001). A primary performance standard is a minimum 5 log reduction of the pathogens of concern in the juice being processed (FDA 2001). The FDA’s approval of ozone as a direct food additive in 2001 triggered interest in ozone applications. A number of commercial fruit juice processors in the USA and Europe began employing ozone for pasteurisation, resulting in the issuance of industry guidelines. However, these guidelines (FDA 2004) highlight gaps in the literature with respect to the critical control parameters of ozone during microbial inactivation in liquid systems.

2.3.2 Overview of European regulations

Application of ozonation in food processing commenced soon after it was first used for water treatment in the early 1900s. The interest in ozone as an antimicrobial agent for food processing is due to several advantages it has over chlorine and other chemical disinfectants presently and previously used in cleaning and disinfection operations. These advantages are generally overlooked by food processors, but the new environmental legislation emerging in Europe, especially IPPC Directive 96/61/EC, is driving changes in the food industry.

Within the EU, among several processing techniques employed in food processing only irradiation and ionisation have specific regulation and labelling rules which also vary within member states (national legislation for irradiation); for other techniques, including ozone, no specific legislation applies. However, there are two general rules which also apply to ozone:

(1) Labelling Directive (2000/13) Indication on the label of the specific treatment undergone by a product – if the absence of this indication would mislead the consumer.

(2) Novel Food Regulation (258/97) Premarket authorisation for ‘novel foods’, including those which have undergone a novel treatment process.

The European Council of Ministers has now adopted a proposal which permits the treatment of natural mineral water, but not spring water, with ozone, provided that the treatment information is carried on the label. The use of ozone is now permitted ‘to separate unstable elements from natural mineral waters which will ensure that the composition of the water as regards its essential ingredients is not affected’. The unstable elements referred to include iron, manganese and sulfur compounds. An important side effect of this new European permission for mineral waters will be the disinfecting capacity of ozone treatment, which in many ways is superior to that of chlorine.

Before the Council vote, the European Union’s Scientific Committee for Food (SCF) handed down an opinion on the use of ozone to treat natural mineral waters. The opinion recognised that ozone treatment may lead to the formation of undesirable byproducts and recommended that producers should comply with several conditions to minimise side reactions. The SCF concluded that residual ozone and the concentration of undesirable byproducts (bromate and bromoform) should be undetectable by the best available analytical methodology.

Regulations in France

In 2003 and 2004, the French Food Safety Agency rendered two Opinions as to the safety of the use of ozone as an auxiliary technology to treat wheat grains before grinding. The first (AFSSA 2003) stated that ‘an ozone dose of 12 g (at standard temperature and pressure) per kg of grain, intended for the preparation of flour for pastries containing simple sugars added to a level of 7 to 50% of dry weight, does not present any health risk to the consumer’. The second Opinion (AFSSA 2004) extended the use of ozone from wheat grain treatment before grinding to ‘the preparation of flour destined for bread and baked products containing up to 7% of added sugars at a concentration of 8 g ozone per kg of grain at standard temperature and pressure, exclusive of traditional French bread’, which it described as posing no health risk to the consumer.

Ozonation of fresh produce

Hammond (2004) outlined the situation in Europe and discussed possible changes in regulations that may be introduced for fresh produce washing. The European Council Directive (89/107/EEC) on food additives lists the substances which legally may be added to food if they perform a useful purpose, are safe and do not mislead the consumer. The detailed controls made under the Framework Directive are implemented into the national law of each EU member state and stipulate which food additives are permitted for use, the specific purity criteria and the conditions of use, including maximum levels for specific additives; however, ozone currently is not on this list. There are opportunities to use other substances for produce decontamination, providing that they function as ‘processing aids’, which are defined as: ‘any substance not consumed as a food itself, intentionally used in the processing of raw materials, foods or their ingredients to fulfil a certain technological purpose during treatment and processing and which may result in the unintentional but technically unavoidable presence of residues of the substance or its derivatives in the final product, provided that these residues do not present any health risk and do not have any technological effect on the finished product’. Chlorine and chlorine dioxide, which are used for fruit and vegetable washing, are regarded as ‘processing aids’. Thus, they would appear to be outside the scope of the biocide controls as they are ‘defined’ in Directive 89/107/EEC.

Whether a washwater chemical is an additive or processing aid is of significance, since it is unlikely that a ‘natural’ agricultural product (such as leafy salad) which carries the name of a chemical additive on the label will appeal to consumers. Therefore, in practice, washwater decontaminants must be able to be classed as processing aids, which requires they have no lasting technological effect on the produce, a key challenge for the chemical sciences (RSC 2009).

The European Commission is planning to develop more detailed regulations governing the use of processing aids. Although it is at a very early stage of development, one possibility being considered is that the definition of a processing aid will be tightened, so that residues of processing aids in a final food will no longer be acceptable, unless the substance in question is specifically authorised for food use. Legislation on processing aids is not yet harmonised at the European Community level, and so processing aids that may be used legally in the UK and France might not be permitted in other member states. A global approach to processing aids is needed to control the agents which are essential for the minimisation of the potential transmission of pathogens from water sources to produce. The risk from pathogens is not eliminated by using large quantities of water; the risk of pathogen cross-contamination is only avoided by using processing aids.

2.3.3 Overview of Canadian regulations

Ozone is permitted for use in Canada as a food additive according to certain provisions that are listed in the Health Canada Food and Drug Regulations (Table VIII, section B.16.100). Ozone may be used as a maturating agent in cider and wine and as a chemosterilant in packaged mineral or spring waters. All of these uses should be consistent with a level of use defined by Good Manufacturing Practice (GMP).

Health Canada has not objected to the use of weakly ozonated water (up to 2 ppm) for fresh fruit/vegetable processing (e.g. flume water, transportation, water in tanks for temporary storage, etc.). Such applications of ozone are aimed at sanitising water rather than acting as a preservative on vegetables. Some petitioners carry out research to determine exact parameters of ozone concentration on fruits and vegetables. As a function of the system design these concentrations may vary; that is, they may be lower than 2 ppm.

Health Canada also has not objected to the use of ozone for the purpose of sanitising water in general in food industry premises (without direct food contact). Egg shell may be treated with ozonated water (up to 2 ppm) for decontamination. Very weak concentrations of ozone, below 1 ppm, may be used as a pesticide, against plant decay, in cold storage facilities for fresh vegetables. Such applications of ozone are considered by the Pest Management Regulatory Agency (PMRA) of Health Canada. The Food Packaging and Incidental Services Section responds to petitioners wishing to obtain ‘no-objection opinions’ from Health Canada, which are issued for application of ozone on food-contact surfaces and air in contact with food. That section also enables certain concentrations of ozone as a means to decontaminate the hands of food plant personnel.

The application of ozone to the water supply, including recirculated washwater, is permitted by Health Canada as an acceptable water treatment provided that the following conditions are met:

(1) The amount of ozone added to the water does not exceed the minimum level required to effectively reduce the microbial levels in the water (including water to make ice), in accordance with GMPs. A processor and the manufacturer of the ozone-generating equipment should determine and validate the amount of ozone needed to achieve disinfection and no more than that amount should be added.

(2) The concentration of residual (remaining) ozone in the water that may come into direct contact with the fresh food is negligible. In other words, GMPs are applied, and no more ozone other than that which is needed for disinfection is applied to the water, resulting in minimal or no residual ozone.

(3) If present, residual (remaining) ozone in recirculated washwater should not bring about a change in the characteristics of the fresh food and will be removed (e.g. filtered) from the washwater prior to its contact with produce or poultry carcasses/parts.

(4) The ozone in the system is not used for the purpose of preservation of the fresh food.

(5) The ozone generator does not generate ozone into the air, incidental to its normal operation, at a level in excess of 0.05 ppm (Health Canada 2007).

The current Health Canada regulations for bottled water require that producers who add ozone to mineral water or spring water must include a statement to this effect on the principal display panel of the product label. Also, rules governing food additives require that the added ozone be listed as an ingredient. So under the current regulations, ozone, when added to spring water or mineral water, must be listed on the product label twice: in the products list of ingredients and in a separate statement on the principal display panel.

2.3.4 Overview of Australian and New Zealand regulations

In Australia, ozone treatment is regarded as a processing aid in the Food Standards Code (FSANZ 2006) Standard 1.3.1, Clause 11. There are currently no restrictions on its use, as long as GMP is followed. In the Australian Food Standards Code, mineral water is defined as ‘ground water obtained from subterranean water-bearing strata that, in its natural state, contains soluble matter’. It is used synonymously with the term ‘spring water’. The Code permits various treatments of mineral water, including UV sterilisation, pasteurisation and ‘ozone treatment’. Table 2.2 lists the main disinfecting compounds currently permitted by Standard A16 of FSANZ for use as washing agents/processing aids.

Table 2.2 The main disinfecting compounds currently permitted by FSANZ Standard A16 that may be used as washing agents/processing aids.

Disinfecting agent Standard A16 permission
Chlorine Group II – bleaching agents, washing and peeling agents
Chlorine dioxide
Calcium hypochlorite
Sodium chlorite
Sodium hypochlorite
Hydrogen peroxide
Peracetic acid
Ozone
Sodium hydroxide Generally permitted processing aids
Phosphoric and sulfuric acids

2.3.5 Overview of Japanese regulations

In the mid-1990s, ozone was approved for food processing in Japan. As of 2006, there were more than 500 ozone-based gas or water treatment installations in the food industry throughout Japan, and more than 100 000 food treatment plants processing a wide variety of foods and food products (Naito and Takahara 2006). This widespread application is a clear indication of the efficacy and usefulness of ozone in the food industry.

2.4 Global harmonisation of food safety regulations

The Global Harmonization Initiative (GHI) was initiated in 2004 as a joint activity of the US-based Institute of Food Technologists (IFT) International Division and the European Federation of Food Science and Technology (EFFoST) as a network of scientific organisations and individual scientists with the goal of working together to promote harmonisation of global food safety regulations and legislation. GHI aims at ‘Achieving consensus on the science of food regulations and legislation to ensure the global availability of safe and wholesome food products for all consumers’. GHI facilitates global discussion about the scientific issues that support decisions made by national governments and international regulatory bodies by:

(1) Providing the foundation for sound, sensible, science-based regulations.

(2) Creating a forum for scientists and technologists to interact with regulatory authorities, globally.

(3) Providing industry, regulators and consumers an independent, authoritative information resource.

This global initiative should facilitate the continued adoption of ozone as a safe and environmentally friendly technique for the food processing industries.

References

AFSSA (2003) Opinion on the use of ozone as an auxiliary technology for the treatment of wheat grains before grinding for flours incorporated into pastries containing simple sugars, AFSSA, Saisine No. 2003-SA-0055, 24 July 2003.

AFSSA (2004) Opinion on the use of ozone as an auxiliary technology for the treatment of wheat grains entering into the composition of bread and baked products, excluding traditional French bread, AFSSA, Saisine No. 2004-SA-0161, 21 Sept. 2004.

Boyce, T.G., Swerdlow, D.L. and Griffin, P.M. (1995) Escherichia coli O157:H7 and the hemolytic–uremic syndrome, New England Journal of Medicine, 333: 364–8.

CFR (1997) Air Contaminants, Title 13, Part 1910, Washington, DC: Office of Federal Register.

FDA (1995) Beverages: bottled water; final rule, Food and Drug Administration, Fed. Reg., 60: 57 075–130.

FDA (2001) Hazard analysis and critical point (HACCP): procedures for the safe and sanitary processing and importing of juice; final rule, Federal Register, 66: 6137–6202.

FDA (2003) Code of Federal Regulations, Title 21. USA: Government Printing Office.

FDA (2004) FDA Guidance to Industry, 2004: Recommendations to processors of apple juice or cider on the use of ozone for pathogen reduction purposes. Retrieved from http://www.cfsan.fda.gov/∼dms/juicgu13.html.

Graham, D.M., Pariza, M.W., Glaze, W.H., Erdman, J.W., Newell, G.W. and Borzelleca, J.F. (1997) Use of ozone for food processing, Food Technology, 51(6): 72–6.

Hammond, J. (2004) The legislative control of substances used for produce decontamination, Washing and Decontamination of Fresh Produce Forum, Chippin Campden, Gloucestershire, UK: Campden and Chorleywood Food Research Association Group, Newsletter, 5(December).

Hampson, B.C. (2001) Emerging technology: ozone. Presented at the IFT Annual Meeting, New Orleans, LA, 2001.

Health Canada (2007) Proposed Regulations for Intentional Ozone Generators. Retrieved from http://www.hc-sc.gc.ca/cps-spc/legislation/consultation/ozone-eng.php.

Hill, A.G. and Rice, R.G. (1982) Historical background, properties and applications, in Rice, R.G. and Netzer, A. (eds) Handbook of Ozone Technology and Applications, Vol. 1, Ann Arbor, MI: Ann Arbor Science Publishers, pp. 1–37.

IFPA (2001) Food Safety Guidelines for Fresh-cut Produce Industry, 4 edn, Alexandria, VA: IFPA.

Mahapatra, A.K., Muthukumarappan, K. and Julson, J.L. (2005) Applications of ozone, bacteriocins and irradiation in food processing: a review, Critical Reviews in Food Science and Nutrition, 45: 447.

Naito, S. and Takahara, H. (2006) Ozone contribution in food industry in Japan. Ozone: Science & Engineering, v28(6): 425–9. Retrieved from http://www.informaworld.com/smpp/title ∼db=all∼content=t713610645∼tab=issueslist∼branches=28.

USDA FSIS (2001) Letter from Robert C. Post (FSIS, Washington, DC) to Mark D. Dopp (Am. Meat Institute, Arlington, VA) dated Dec. 21.

Vojdani, J.D., Beuchat, L.R. and Tauxe, R.V. (2008) Juice-associated outbreaks of human illness in the United States, 1995 through 2005, Journal of Food Protection, 71(2): 356–64.