Microbial Decontamination in the Food Industry

Novel Methods and Applications

Ali Demirci, Michael O Ngadi

• Publisher: Woodhead Publishing
• Year: 2012
• Print ISBN: 9780857090850
• eBook ISBN: 9780857095756
• Topic: Technology & Engineering
• Subtopic: Food Science
• Index: Technology & Engineering

The problem of creating microbiologically-safe food with an acceptable shelf-life and quality for the consumer is a constant challenge for the food industry. Microbial decontamination in the food industry provides a comprehensive guide to the decontamination problems faced by the industry, and the current and emerging methods being used to solve them.Part one deals with various food commodities such as fresh produce, meats, seafood, nuts, juices and dairy products, and provides background on contamination routes and outbreaks as well as proposed processing methods for each commodity. Part two goes on to review current and emerging non-chemical and non-thermal decontamination methods such as high hydrostatic pressure, pulsed electric fields, irradiation, power ultrasound and non-thermal plasma. Thermal methods such as microwave, radio-frequency and infrared heating and food surface pasteurization are also explored in detail. Chemical decontamination methods with ozone, chlorine dioxide, electrolyzed oxidizing water, organic acids and dense phase CO2 are discussed in part three. Finally, part four focuses on current and emerging packaging technologies and post-packaging decontamination.With its distinguished editors and international team of expert contributors, Microbial decontamination in the food industry is an indispensable guide for all food industry professionals involved in the design or use of novel food decontamination techniques, as well as any academics researching or teaching this important subject.- Provides a comprehensive guide to the decontamination problems faced by the industry and outlines the current and emerging methods being used to solve them- Details backgrounds on contamination routes and outbreaks, as well as proposed processing methods for various commodities including fresh produce, meats, seafood, nuts, juices and dairy products- Sections focus on emerging non-chemical and non-thermal decontamination methods, current thermal methods, chemical decontamination methods and current and emerging packaging technologies and post-packaging decontamination

Part I

Microbial decontamination of different food products

1

Microbial decontamination of fresh produce

S. Foong-Cunningham, Ecolab Inc., USA

E.L.C. Verkaar, Ecolab Deutschland GmbH, Germany

K. Swanson, Ecolab Inc., USA

Abstract:

Fresh fruit and vegetable consumption has increased dramatically in the past four decades, and fresh produce has been associated with multiple foodborne illness outbreaks involving bacteria, viruses and parasites. Since there is usually no terminal inactivation step prior to consumption, there is great concern over the safety of these products. This chapter discusses fresh produce in the raw or minimally processed state with general information on epidemiology, processing steps, good agricultural practices (GAP) and decontamination strategies. Details of pathogen, produce type and contamination pathways are provided. This chapter also focuses on decontamination methods commonly used in certain regions for fresh produce, recognizing that some antimicrobials may not be approved in some regions. Considerations for comparing the effectiveness of different treatments are addressed, as is the type of application. Chlorine and electrolyzed oxidizing water, chlorine dioxide, acidified sodium chlorite, organic peroxides, hydrogen peroxide, ozone, organic acids, and mild heat treatments are discussed. Novel treatments such as irradiation, essential oils, high hydrostatic pressure and atmospheric plasma inactivation are briefly discussed. Future trends for produce decontamination and differences in approaches among regions of the world are included in this chapter. Understanding the standards related to produce decontamination for different regions of the world is important to determine the proper intervention to use.

Key words

fresh produce

decontamination

antimicrobial

chlorine

electrolyzed water

chlorine dioxide

acidified sodium chlorite

organic peroxides

hydrogen peroxide

ozone

organic acids

1.1 Introduction

During the past few decades fresh fruit consumption in the US has increased by 25.8% and fresh vegetable consumption by 32.6% (Barth et al., 2010). Factors influencing this trend include changes in consumers’ dietary habits, shifts in social demographics, more ‘outside-home’ meals, the growing popularity of salad bars, and recommendations to increase consumption of fruits and vegetables as part of a healthy diet.

The term ‘produce’ includes the edible components of plants such as leaves, stalks, roots, tubers, bulbs, flowers, fruits, sprouted seeds, and mushrooms. Many fresh produce items are frequently consumed without cooking and in many countries they are considered as raw agricultural commodities that come directly from the field, orchard, or vineyard. Fresh produce, especially vegetables, can be trimmed, rinsed, or washed prior to shipment to the market. Sliced or cut ready-to-eat produce is part of a rapidly growing segment of the food industry in North America, Europe and elsewhere. Once cut, different types of produce are sometimes blended together prior to sale. Much fresh produce is ready to eat in the form of salads and fruit blends.

The link between contaminated fresh produce and outbreaks of foodborne illness is well recognized. Some cultures have a tradition of thorough cooking of produce prior to consumption and others rely on good agricultural and processing practices to minimize the risk of foodborne illness. Travelers’ diarrhea is frequently associated with contaminated produce, hence the US Centers for Disease Control and Prevention (CDC) recommends that travelers avoid eating raw fruits and vegetables in regions where travelers’ diarrhea is a concern unless they are able to peel the produce (CDC, 2006b). Even in developed countries, fresh produce is associated with outbreaks. From 1998 to 2006, five commodity groups comprised 76% of produce-related US outbreaks; i.e., lettuce/leafy greens, tomatoes, cantaloupe, herbs (basil, parsley), and green onions (Stopforth et al., 2008). In 2007, produce was associated with 24% of outbreaks attributed to a single food commodity in the US, with 14% attributed to leafy green vegetables alone (CDC, 2010c). The Rapid Alert System for Food and Feed (RASFF) system in Europe provides an effective tool to exchange information about measures taken to respond to serious food and feed risks (EU, 2011). Approximately 10–15% of EU border rejections, alerts, and information notifications are associated with fruits, vegetables, herbs, and spices. The microbiological hazards for herbs, spices, fruits, and vegetables in the RASFF system are mainly Bacillus cereus, Campylobacter, E. coli, norovirus, Salmonella, and Shigella spp.

Leafy vegetables and fruits/nuts are the most common types of produce items associated with outbreaks from a single food, while fish, poultry and beef are each associated with more outbreaks (CDC, 2009b, 2010c). In Europe, sources of foodborne illnesses are also more frequently associated with fresh meat products than with produce items; however, produce safety is still a concern.

The increase in reported foodborne illness associated with consumption of raw produce can, in part, be attributed to improved surveillance systems as well as insufficient hygiene practices, changes in global trade, increased frequency of consuming meals at food service establishments and produce production, processing, and marketing practices (Park and Beuchat, 1999). The increased per capita consumption of fresh and minimally processed produce, as well as increased imports from regions where good agricultural practices may not be practiced, results in the elevated interest in fresh produce safety.

1.1.1 Microorganisms in fresh produce

Fresh vegetables and fruits that have not been exposed to raw human or other animal waste material generally do not contain human pathogens. However, direct contamination can occur through several routes including raw sewage or manure fertilizer; contaminated water for irrigation, cooling or washing; contaminated ice for display or transport; and unhygienic handling. Indirect contamination can also occur during preparation of food where fresh produce is contaminated by other foodstuffs through cross-contamination such as using the same cutting board used for meat preparation and fresh produce preparation. These potential sources of contamination must be controlled for produce that is intended to be consumed raw.

Intact cell structures of a plant act as a protective barrier against contamination of microorganisms. Once this barrier is compromised through aging, wilting, or injury (chopping, bruising, shredding, and juicing), both spoilage and pathogenic microorganisms may be able to grow due to the availability of nutrients and moisture within the plants. Pathogens causing human diseases include bacteria, viruses, and parasites. Common produce/pathogen pairings include Salmonella in fruits/nuts and in vine-stalk vegetables, norovirus and Shiga toxin-producing E. coli (STEC) in leafy vegetables (CDC, 2009b, 2010c).

Many foodborne illnesses associated with fresh produce consumption are influenced by the type of produce, the physical conditions (e.g. temperature) under which the produce is handled and stored, and the amount consumed. For instance, melons are commonly associated with outbreaks and several types, such as cantaloupe, have intricate, webbed surfaces on the rind. These surfaces make pathogenic bacterial attachment harder to remove and can provide protection against antimicrobials. When the melon is cut, microorganisms from the surface are transferred to the cut fruit surface. Cut melons have been documented to support growth of pathogens (Park and Beuchat, 1999) and therefore once cut should be stored at or below 7 °C and displayed for < 4 hours if not chilled (ICMSF, 2005).

Availability of fresh-cut tomatoes meets consumer demand for convenience and offers the customer a standardized product. However, cut tomatoes have also been demonstrated to support the growth of Salmonella under improper temperature conditions, thus the risk of illness is increased when cut tomatoes are improperly handled, e.g., during production, handling, processing, storage, or distribution (Zhuang et al., 1995; Prakash et al., 2007a).

Outbreaks associate...

Table of contents

• Cover image
• Title page
• Table of Contents
• Copyright
• Contributor contact details
• Woodhead Publishing Series in Food Science, Technology and Nutrition
• Preface
• Part I: Microbial decontamination of different food products
• Part II: Current and emerging non-chemical decontamination methods
• Part III: Current and emerging chemical decontamination methods
• Part IV: Current and emerging packaging technologies and post-packaging decontamination
• Index