Food Microbiology and Biotechnology

Safe and Sustainable Food Production

Guadalupe Virginia Nevárez-Moorillón, Arely Prado-Barragán, José Luis Martínez-Hernández, Cristobal Noé Aguilar, Guadalupe Virginia Nevárez-Moorillón, Arely Prado-Barragán, José Luis Martínez-Hernández, Cristobal Noé Aguilar

• Éditeur: Apple Academic Press
• Année: 2020
• ISBN:
  9781000449013
• Édition: 1
• Sujet: Business
• Sous-sujet: Industria farmaceutica, biotecnologica e sanitaria

Food Microbiology and Biotechnology: Safe and Sustainable Food Production explores the most important advances in food microbiology and biotechnology, with special emphasis on the challenges that the industry faces in the era of sustainable development and food security problems.

Chapters cover broad research areas that offer original and novel highlights in microbiology and biotechnology and other related sciences. The authors discuss food bioprocesses, fermentation, food microbiology, functional foods, nutraceuticals, extraction of natural products, nano- and micro-technology, innovative processes/bioprocesses for utilization of by-products, alternative processes requiring less energy or water, among other topics. The volume relates some of the current developments in food microbiology that address the relationship between the production, processing, service and consumption of foods and beverages with the bacteriology, mycology, virology, parasitology, and immunology.

Demonstrating the potential and actual developments across the innovative advances in food microbiology and biotechnology, this volume will be of great interest to students, teachers, and researchers in the areas of biotechnology and food microbiology.

PART I
Food Microbiology

CHAPTER 1

Hurdle Technologies for the Control of Microbial Growth in Food

ADDÍ RHODE NAVARRO-CRUZ, RAÚL ÁVILA-SOSA, OBDULIA VERA-LÓPEZ, and CARLOS ENRIQUE OCHOA-VELASCO

Department of Biochemistry and Food, School of Chemistry, Meritorious Autonomous University of Puebla, 72420 Puebla, Puebla, México, Tel.: [phone], E-mail: [email protected] (C. E. Ochoa-Velasco)

ABSTRACT

Microbial growth in food can cause deterioration and eventual spoilage of foods; food can also be the carrier of foodborne pathogens, causing a considerable public health problem. The control of microbial growth in food can be achieved by the modification of intrinsic and extrinsic factors, but processing technologies can have deleterious effects on food properties. The use of combined processing methods with mild antimicrobial capacities can lead to control of microbial growth, but without severe damages to food. The description of traditional and novel food processes used in hurdle technologies is revised in this chapter.

1.1 INTRODUCTION

The growth of microorganisms in food is one of the multiple causes of deterioration and is also related to foodborne diseases. The term food preservation refers to all the measures taken against any food spoilage microorganisms [1]. Unfortunately, in developing countries, more than 50% of fresh food is wasted due to the limited knowledge of food preservation [2]. Several intrinsic and extrinsic factors can affect microbial growth in food. Endogenous enzymes, substrates, sensitivity to light, oxygen content, pH, water activity (A_w), and oxide-reduction potential are considered intrinsic properties, while the relative humidity, temperature, presence, and activities of other microorganisms are extrinsic factors. The intrinsic and extrinsic factors can have either bactericidal/fungicidal or bacteriostatic/fungistatic effects. The combination of some or all of these factors and their control is one of the remaining challenges for food science [1, 3]. In recent years, it has been observed that pathogens associated with foodborne infections are more resistant and host-adapted to traditional food preservation methods. Therefore, different strategies such as the application of different factors simultaneously or sequentially called hurdles (generally known as combined methods, a combination of preservation factors, combined processes, barrier technology or combination techniques), have been developed to achieve a more gentle and effective microbial growth control. The combination of these factors can act synergistically in their antimicrobial capacity, using different mechanisms for inhibition or inactivation and assuring reduced costs of energy and maximizing processing output [4–7]. Therefore, this chapter gives an overview of the most important hurdle technologies (novel and conventional) to control foodborne and deteriorative microorganism’s growth in food.

1.2 HURDLE TECHNOLOGY

Hurdle technology from the food safety point of view should be understood from two different aspects that may include conventional methods [8]:

1. 1. Common Methods of Food Processing and Preservation: That implies a change in product nature that reduces microbial load or limits its growth.
2. 2. Conventional Methods of Extending Shelf Life: It is based on changing the product storage and packaging conditions to inhibit microbial growth.

Both methods may include heat treatment, smoking, irradiation, freezing, canning, meat curing, as well as salting, drying, and dehydration, osmotic concentration, the addition of antimicrobials and other additives [9]. The exact method to be used will depend on the product, product safety and process facilities [10], since when hurdle technology is intelligently selected and then intentionally applied, causes a hostile environment to the microorganisms inhibiting their growth or shorter their survival or cause their death [5, 11, 12]. No single factor is responsible for making the product stable, but rather the stability results from the synergism among the combined factors [13]. The physiological response of microorganisms during food preservation (homeostasis, metabolic exhaustion, and stress reactions) is the basis for the application of hurdle technology [5, 13]. Homeostasis is the process which maintains the stability of the living cell’s internal environment. Hurdle technology success fundamentally depends on guaranteeing the metabolic depletion of microorganisms; treatments to be used as barriers must be based on different principles in order to alter one or more of homeostasis mechanisms, and to prevent microorganisms from multiplying, whether they remain inactive or are eliminated [1, 5]. Therefore, each technique used as a barrier must be in proper combination and at optimum level to minimize the damage to the overall food quality [14]. Microorganisms stress reactions are active processes that involve the expenditure of energy mainly by stress proteins synthesis induced by heat, pH, aw, ethanol [15].

Metabolic combining inhibitory factors can result in a significant improvement in securing microbial safety and stability as well as the sensory, nutritional quality, and economic viability of foods [16, 17]. In recent years, food safety research has often focused on growth/no growth factors in almost all food products preserve by hurdle methods, and empirical experiments determine the number of hurdles and their types. However, it is still a challenging issue, the use of methods for assessing food stability [2, 18]. In developing countries, hurdle technology is proved to be useful for novel foods which despite minimally processing are ambient stable, as well as in modifications of traditional intermediate-moisture foods to make them ambient stable high-moisture foods [13]. The magnitude of microbial reduction achieved through the use of hurdles will vary depending on circumstances in primary production whether a substantial microbial burden (both pathogens and spoilage organisms) is assumed or not [17].

1.3 CONVENTIONAL HURDLE TECHNOLOGIES

Hurdle technology involves the use of several preservation techniques in combination, which reduces the intensive use of a conservation technique that produces a lesser impact on sensory quality. However, it should not be forgotten that a positive reaction to one or several treatments depends on the food that is used. It is necessary to carry out studies that allow identifying which is the sequence of treatments necessary to obtain a synergic effect and in this way produce a barrier effect that allows the extended shelf life of any food [19–23]. Each food process method has the goal to preserve or extend food useful life, such as the addition of preservatives as a commonly used technique. Fruits and vegetables are especially fragile and highly susceptible to rot, so there are many reports on their conservation by hurdle technology, jams, and jellies are the most classic example of hurdle technology applications, which combine the use of high temperatures, low pH, decreased A_w and anaerobic packaging to reduce the initial microbial load and inhibit the growth of survivors [24–27]. Those extreme modifications might not be necessary using hurdle technology; since obstacle technology is based on minimally processed methods, such as in mixtures of vegetables, combining disinfection, heat treatment, edible coatin...