Process-Induced Food Toxicants: Occurrence, Formation, Mitigation, and Health Risks - Rilegato

Rilegato

ISBN 10: 0470074752 ISBN 13: 9780470074756

Casa editrice: John Wiley & Sons Inc, 2008

Riassunto

Process-Induced Food Toxicants combines the analytical, health, and risk management issues relating to all of the currently known processing-induced toxins that may be present in common foods. It considers the different processing methods used in the manufacture of foods, including thermal treatment, drying, fermentation, preservation, fat processing, and high hydrostatic pressure processing, and the potential contaminants for each method. The book discusses the analysis, formation, mitigation, health risks, and risk management of each hazardous compound. Also discussed are new technologies and the impact of processing on nutrients and allergens.

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Informazioni sull?autore

RICHARD H. STADLER, PHD, is the head of the Quality Management Department at the Nestlé Product Technology Center in Orbe, Switzerland.

DAVID R. LINEBACK, PHD, is the Director (Retired) of the Joint Institute for Food Safety and Applied Nutrition (JIFSAN) at the University of Maryland.

Dalla quarta di copertina

A COMPREHENSIVE LOOK AT ANALYTICAL, HEALTH, AND RISK MANAGEMENT ISSUES

Process-Induced Food Toxicants provides a much-needed single-source reference on food process toxicants that also answers important food safety questions. The text presents currently known toxicants, and includes a balanced view, given by renowned experts in industry, academia, and the regulatory field, of mitigation options, risk assessment, and risk management for these compounds.

The text begins by considering different processes used in the manufacture and processing of foods—including thermal treatment, drying, fermentation, preservation, and high hydrostatic pressure processing—and examines the risks of potential contaminant/toxicant formation as they relate to each processing method. For each subject covered, the book offers a consistent approach featuring:

• Occurrence in food
• Methods of analysis
• Mechanisms of formation
• Approaches to mitigation/reduction
• Human exposure through the food supply
• Potential health risks
• Risk management

Process-Induced Food Toxicants gives readers the latest information based on results from recent research, as well as new technological and methodological developments and how they bear on mitigation. These include both analytical methodologies and practical systems such as HACCP for managing food safety concerns. Process-Induced Food Toxicants provides a wide range of students and professionals in food science, food technology, toxicology, public health, public policy, and other related disciplines with a unique, comprehensive, and invaluable resource.

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Process-Induced Food Toxicants

Occurrence, Formation, Mitigation, and Health RisksBy Richard H. Stadler David R. Lineback

John Wiley & Sons

Copyright © 2009 John Wiley & Sons, Inc.
All right reserved.
ISBN: 978-0-470-07475-6

Chapter One

INTRODUCTION TO FOOD PROCESS TOXICANTS

David R. Lineback and Richard H. Stadler

1.1 HISTORY AND ROLE OF FOOD PROCESSING

Food processing and preservation, the traditional focus of food science and technology, have played, and continue to play, important roles in achieving food sufficiency (availability, quality, and preservation) for the human race. These practices originated in recognition of a need to improve the edibility of many food sources and to maintain food supplies for longer periods of time than their seasonal availability. With the transition from a hunter-gatherer society to life in villages and early agriculture, this need became even greater and emphasis on food preservation became increasingly important. This, of course, was paralleled by the development of processes/processing of animal, vegetable, and marine raw materials into usually more palatable, portable, and nutritionally dense foods. In many cases, if not most, this occurred in a fortuitous, rather than planned, manner as natural causes of food processing and preservation were observed and adapted to human use.

Food processing involves the actions taken from the time a raw product (crop, animal, fish) is harvested, slaughtered, or caught until it is sold to the consumer. By this process, the parts regarded as most valued are separated from by-products or waste. Equally enhanced is the palatability/digestibility of foods, illustrated in the transformation of baking flour into bread, to maintain or increase quality attributes and to ensure safety. Increasing understanding of the science involved in food loss, deterioration of quality, and means of improving the palatability of foods has resulted in development of the sophisticated methods of food processing and preservation now in use. The work of Pasteur, resulting in identification of the role of microorganisms in food spoilage and development of technology leading to canning by Nicolas Appert in 1809, can be considered initial steps in the development of modern food processing and preservation. As the world population continues to grow, resulting in increasing requirements and demands for food availability and safety, new and improved methods of food processing and preservation are needed and in development.

The term "minimal processing" is frequently used to describe foods, such as vegetables, that are harvested, sorted, and washed (or similar minimal invasive procedures) before distribution and sale. This is done to distinguish these more "natural" products from those that undergo more extensive processing procedures. Over the last years the development and distribution of minimally processed foods has been increasing steadily. This trend has been triggered by the demand for fresh and convenient products as well as for more natural products, i.e., less processed or containing less salt, sugar, or preservatives.

Such foods range from fruits and vegetables, which are usually only submitted to washing (with or without biocides), trimming, slicing, or shredding, to prepared foods processed by applying minimal bactericidal treatments in combination with different physicochemical hurdles to ensure their stability and safety. These foods represent certainly a challenge to manufacturers since no or only minimal killing steps are applied, and, at the same time, requirements for more global availability and longer shelf life are increasing. The fact that these challenges are frequently underestimated or not mastered sufficiently is illustrated by the occurrence of numerous incidents linked to a variety of products involving different pathogens. Outbreaks related to minimally processed foods often encompass chilled foods such as sous-vide products, pasteurized vegetables, and baked potatoes, which have frequently been linked to Clostridium botulinum intoxication.

Early types of processing/preservation evolved from observations of natural processes, e.g., drying, curing (such as salting), smoking, fermentation, and reducing storage temperature (refrigeration or freezing). Salting and smoke processing originated at the beginning of human civilization, mainly employed to preserve meat and fish. In fact, salting, pickling, and drying continued as the primary means of preserving foods until the twentieth century and the advent of mechanical refrigeration. More modern means of preservation precluded the use of copious amounts of salt, exemplified by the far reduced concentrations of salt in ham today (<2%) versus that in hams produced in the first half of the twentieth century (>6%). Changes to technologies were also introduced a few decades ago with regard to cured meats and residual nitrite content. Nitrite, used to cure meat, acts as a preservative against Clostridium botulinum and other spoilage bacteria. However, during the 1970s, concern arose due to the role of nitrites in the formation of carcinogenic nitrosamines (Chapter 4.1), as well as its contribution to the body burden. In modern cured meats, the nitrite amounts have decreased and are typically one-fifth of those found some 30 years ago. Moreover, the use of ascorbate-an effective inhibitor of nitrosamine formation-is an additional mitigation measure introduced in the production of most cured meats.

Smoke processing is still used today to preserve meat, especially in tropical countries. Smoke imparts appealing organoleptic properties, with concomitant preservation of nutrients. However, concern has been raised about the presence of both polycyclic aromatic hydrocarbons (PAHs) and nitrosamines in smoked foods. PAHs are covered in Chapter 2.8, with special attention to their formation, mitigation, and toxicology. Although the exposure risks in modern manufacture of meats and fish are considered minimal, alternatives to traditional smoking have been developed. Liquid smoke flavorings have gained popularity as they provide the same traits, i.e., desirable organoleptic properties, and preservation through antioxidation and bacteriostasis. Additional benefits include increased product consistency and absence of detectable animal carcinogens. In fact, approximately 75% of hot dogs produced in the United States contain aqueous liquid smoke flavorings.

Food preservation can be considered part of or an extension of food processing, since it involves the use of procedures to prevent or reduce spoilage of foods. Examples include the inactivation of enzymes and microorganisms by heating or reduction of moisture content, use of antimicrobial compounds, pasteurization (heat or irradiation), freezing, modified atmospheric packaging, and fermentation.

Techniques that have been used in food processing and preservation include:

Drying/dehydration

Curing

Smoking

Fermentation

Canning

Pasteurization (heat or irradiation)

Freezing and refrigeration

Additives

Controlled atmosphere storage

Aseptic packaging

Until the last quarter of the twentieth century, canning was widely used in homes throughout the rural United States. Inadequate heat treatment during the canning process occasionally resulted in severe illness or death caused by Clostridium botulinum that was not inactivated during the heating process and resulted in subsequent formation of the toxin. Commercial canning, while having some outbreaks of botulinum poisoning, became used much more widely due to improved quality, safety, and increased urban populations.

1.2 GENERAL APPROACHES TO FOOD PROCESSING

The rapid growth and development of commercial food processing in the twentieth century has continued and now dominates food processing, particularly in developed countries. However, food processing in the home, such as canning, decreased with increasing urbanization. Although some aspects of food processing still occur frequently in home situations, particularly in developing nations. Food preparation/processing in the home is primarily related to heat treatment, which plays an important role in the formation of desirable flavors, colors, aromas, and textures. In fact, exposure of food to heat can be considered the most used processing step in modern society, involving frying, baking, grilling, roasting, toasting, microwaving, and broiling, using ovens (convection, microwave), stoves, toasters, grills (gas, wood, and charcoal), and fat-based fryers.

There are, however, considerable differences between practices in the home and in commercial industrial settings. Home appliances tend to have less accurate temperature controls, resulting in actual oven temperatures differing considerably from what is indicated by the oven setting or temperature gauge. In general, there is also less rigid timing due to interruptions and delays in homes as contrasted to an industrial environment. High-quality standards are pivotal for industrialized processes, and food manufacturers have identified early on the need for quality control tools and stringent targets to achieve consumer preference in terms of nutritional quality, shelf life, and organoleptic properties at all times. Ideally, quality is addressed early on in the product and process design phase, identifying those process steps that impact (key) quality parameters. For this purpose, modern industrial lines are equipped with appropriate measuring systems/sensors (temperature profiles, moisture content, texture, color, pH, etc.) to deal with raw material variability and process complexity.

1.3 CONCERNS ABOUT FOOD SAFETY DURING FOOD PROCESSING

1.3.1 Types of Hazards

The major hazards considered in food safety are allergens, and those that are microbiological, physical, and chemical in nature.

Microbiological contamination with pathogens such as enterohemorrhagic Escherichia coli strains, Listeria monocytogenes, and Salmonella spp. represents a major problem in modern food safety (pathogen identification, control, and prevention). It is considered the most important aspect of improving food safety globally, displacing the emphasis on chemical contaminants of previous decades. For further reading, various books and reviews on this topic can be consulted (see References 6 and 7).

Physical hazards are considered acute hazards if not adequately addressed and controlled and may pose a serious threat to human health (e.g., glass, hard plastic and metal pieces, bones, wood, stones). There are different sources of physical hazards, and the origins of the potential risks must be clearly understood (raw materials/ingredients or the operations in the manufacturing of food per se may be a source of a physical hazard, e.g., potential glass breakage along a glass filling line). Within the frame of Hazard Analysis Critical Control Points (HACCP), measures are identified that remove or reduce such hazards to an acceptable level in the final product (e.g., filtration, sieving, centrifugation). Procedures must be put in place by the manufacturer to verify that the measures to control such hazards are indeed effective (e.g., metal detectors, X-ray machines).

Food allergens are generally recognized as a serious food safety issue and manufacturers are responsible for controlling them and providing concise information to consumers. Through good manufacturing practice (GMP), identifying possible sources of cross contact, integration of allergen hazards into HACCP studies, and appropriate ingredient labeling, the health risks can be minimized.

The chemical hazards in foods can be multiple, and as depicted in Fig. 1.1 may enter the food and feed supply chain at many different points. Traditionally, the environment has been thought to be the origin of many chemical food hazards, such as heavy metals and persistent organic pollutants (POPs). An increased risk of pathogenic microorganisms may also be attributed to the contamination of the agricultural water supply caused by human and animal waste, and use of manure as fertilizer.

Essentially, the potential chemical contaminants in food can be broadly classified into:

(1) natural toxins, e.g., mycotoxins, higher plant toxicants, and marine biotoxins;

(2) environmental contaminants, e.g., heavy metals, dioxins, and radionuclides;

(3) chemicals used as aids in food manufacture and,in the event of a failure, which may contaminate food, e.g., through leakage, spillage, or misuse of lubricants, cleansing agents, or disinfectants;

(4) agrochemical residues, e.g., fungicides, pesticides, and veterinary drugs;

(5) packaging migrants, e.g., isopropylthioxanthone, semicarbazide, and styrene;

(6) processing toxicants, e.g., heterocyclic aromatic amines, acrylamide, and furan.

The latter class of substances is the focus of this book, and the reader is referred to further sources of information on general chemical risks in food (see References 8 and 9).

1.3.2 Definition of a Process Toxicant

Processing toxicants (process-induced toxicants, process-formed toxicants) as used in this book are defined as those substances present in food as a result of food processing/preparation that are considered to exert adverse physiological (toxicological) effects in humans, i.e., substances that create a potential or real risk to human health. Food in this definition also includes beverages and nonalcoholic drinks such as coffee and tea, and thus both parts of the diet are included.

Ingredients commonly occurring in food formulations (recipes) are excellent substrates for chemical reactions occurring under the conditions encountered in food processing. The reaction products formed depend on the processes and conditions used, such as fermentation, irradiation, and heat processing. Products from such reactions can have beneficial properties and/or adverse physiological effects on consumers. Examples of the former include compounds such as antioxidants, anticarcinogens, and those resulting in or contributing to nutritional properties, desirable flavor, aroma, texture, and color in food products. Examples of the latter include carcinogens, genotoxins, neurotoxins, anti-nutrients, and undesirable flavors or aromas. Many of these coexist as a result of being formed during common food processing technologies, particularly those involving heating, e.g., toasting, roasting, frying, broiling, baking, grilling and microwaving.

1.3.3 Progress in Technological Developments

The development of new food processing technologies continues at a rapid pace, with some of these, such as high-pressure processing (HPP), already in commercial use (see Chapters 5 and 8). In fact, the application of HPP is not a new concept, and was already described in certain foods in the late nineteenth century. The use of HPP is not uncommon in foods such as whole shell oysters, salsa, ready-to-eat (RTE) meats, and jams. New technologies are aimed at delivering products with superior organoleptic quality, minimal changes to nutrients, safety, and shelf life (product life, preservation of quality), and ideally the minimal formation of undesirable compounds. Pulsed electric field, ohmic heating, jet impingement, infrared radiation, and new biotechnological applications are just a few that can be considered new processing techniques. Innovative nonthermal processing technologies (photosensitization, pulsed electric field technologies, high-pressure homogenization, and HPP coupled to packaging under inert atmosphere) to improve the quality and safety of RTE meals are being investigated within the European "HighQ RTE" project, with the goal to improve the safety and quality of three representative categories of European RTE foods, i.e., salads, fluid foods, and vegetable-based meals.

(Continues...)

Excerpted from Process-Induced Food Toxicantsby Richard H. Stadler David R. Lineback Copyright © 2009 by John Wiley & Sons, Inc.. Excerpted by permission.
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Dettagli dell'edizione

• Editore: John Wiley & Sons Inc
• Data di pubblicazione: 2008
• Lingua: Inglese
• ISBN 10: 0470074752
• ISBN 13: 9780470074756
• Rilegatura: Copertina rigida
• Numero di pagine: 723
• Redattore: Stadler Richard H., Lineback David R.
• Contatto del produttore: non disponibile
• Persona responsabile: non disponibile