Caballero B. (ed.) Encyclopaedia of Food Science, Food Technology and Nutrition. Ten-Volume Set

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the substrate. The simplest biosensor approach is to

measure amperometrically the oxygen depletion or

hydrogen peroxide production associated with the

reactions involving oxidase enzymes. The combin-

ation of simplicity, ease of manufacture, high sensi-

tivity, availability, and low cost of instrumentation is

highly attractive in this type of devices. A variety of

enzymes belonging to classes of oxidoreductases, hy-

drolases, and lyases have been applied in enzyme-

based sensors. These enzymes can act on fatty acids,

sugars, amino acids, organic acids, and phenols. Bio-

sensors based on the use of redox mediators to shuttle

the electrons, resulting from the catalytic oxidation or

reduction of the substrate of interest, to the electrode

has been an area of great interest to many researchers.

Much of the work is centered on the use of redox

mediator compounds such as ferrocene, TTF, TCNQ,

hexacyanoferrate (III), methylene blue, quinones, and

their derivatives. Careful selection of the mediator

can also eliminate interference problems from other

substances in the sample.

0030 To date, there are several successful biosensor

devices on the market based on the different ampero-

metric transduction principles outlined above. These

include the MediSense mediated blood glucose ana-

lyzer for medical application and the Yellow Springs

hydrogen peroxide-based systems (YSI, Yellow

Springs, OH) developed for both medical and food

analysis and for bioprocess control. The YSI 2700

SELECT

Biochemistry Analyser (Figure 5) can be

used for on-line fermentation monitoring or off-line

sample analysis for food and drink fermentation.

Nutrient and bioproducts analysis can be carried

out using the biosensor system including glucose,

l-lactate, l-glutamine, l-glutamate, ethanol, lactose,

sucrose, galactose, and methanol. Other commer-

cially available biosensors for food analysis include;

Sensomat B10, for alcohol analysis (Gonotec,

Germany); Microzym-L for lactate analysis (Kalger

GmbH, Germany) and Glu-11 for glucose analysis

(TOA Electronics, Japan). A range of single and

multianalyte biosensors based on the same principle

are being developed for a diverse range of applica-

tions in the food industry.

0031The majority of biosensors developed for food

analysis are water-based systems. Organic-phase

enzyme electrodes, however, have been developed to

work in organic solvents and have been used for the

analysis of compounds such as cholesterol, alcohols,

organic peroxides, and phenols. This technique has

the advantages of ease of sample preparation from

materials, such as fats and oils, and increased enzyme

stability. In principle, analytes soluble in fatty sub-

stances can also be measured using biosensors.

Enzyme biosensors have also been widely applied to

the detection of phenolic compounds. Contamination

by these aromatic compounds results from the pro-

duction of drugs, dyes, and antioxidants and also

from the paper and pulp industry. Enzymes used in

biosensor development for this type of compounds

are phenol oxidases (tyrosinases), laccases, and per-

oxidases.

0032Biocatalytic sensors based on enzyme inhibition are

the most commonly reported biosensors for the detec-

tion of toxic compounds and heavy metal ions. These

sensors are based on the selective inhibition of specific

enzymes by classes of compounds, or by more general

inhibition of enzyme activity. The measurement of the

enzyme activity can be used as a screening test to

evaluate the contamination by compounds such as

organophosphorous and carbamate insecticides and

the triazine herbicides and other compounds that

display similar toxicological behavior. Enzymes used

include: choline esterase, horse-radish peroxidase,

polyphenol oxidase, urease, and aldehyde dehydro-

genase.

0033Biosensors based on the use of whole cells as

the sensing layer generally respond to more than

one analyte, but can offer increased stability when

compared with enzyme-based sensors. Whole-cell

biosensors have been utilized commercially for envir-

onmental monitoring and capitalize on the broad

sensitivity of microorganisms to a wide range of

toxins. Whole-cell biosensors may contain living bac-

teria, yeast, fungi, plants, or animal cells. Biosensors

able to monitor indicators of pollution, such

as biochemical oxygen demand (BOD), have been

developed. Sensors such as the ARAS BOD Biosensor

System (Dr Bruno Lange GMbH, Du

sseldorf,

fig0005 Figure 5 YSI 2700 SELECT

Biochemical Analyzer. Photo

courtesy of YSI incorporated, Yellow Springs, USA.

BIOSENSORS 495

Germany), the BOD module biosensor produced by

(Prufgerate-Werk Medigen, Germany), and Nissin’s

(Japan) BOD Sensor are commercially available. A

range of biosensors based on this principle have been

developed for polluting compounds such as pesti-

cides, in particular for water monitoring.

0034 Electrochemical sensor approaches to hygiene

monitoring based on the metabolism of living cells

have also been commercialized. The Bactometer (Bac-

tomatic Inc., Princeton, NJ) and the Malthus 2000

(Malthus, Stoke-on-Trent, UK) use impedance and

conductance, respectively, to plot bacterial growth.

A more rapid approach is the use of amperometry.

The method comprises the use of mediators to detect

the metabolic activity of the cells, and the resulting

current can be related to the numbers of organism

present in the sample.

0035 Catalytic optical biosensors are usually based on

optical fibers or planar wave-guide films. Various

fiber-optic biosensors based on pH opt(r)odes have

been constructed for glucose, urea, penicillin, and

creatinine analysis. Commercial examples of fiber

optic sensors for monitoring blood pH, dissolved

oxygen and carbon dioxide concentrations. The

transfer of these technologies to the agrofood and

environmental sector can be anticipated in the near

future.

Affinity Sensors

0036 Antibodies have been used as recognition elements in

tests and assays since the 1950s and in biosensor

devices since 1970s. In the past decade, there has

been phenomenal growth in affinity-based sensor re-

search and development. Affinity-based sensors can

be define as analytical devices that use an antibody,

receptor protein, or other molecules with affinity-

recognition powers interfaced to a signal transducer

to measure a binding event. Various research groups

have pioneered different types of affinity-based sensor

configurations. By utilizing the immunorecognition

properties of antibodies in immunosensors and affin-

ity sensors, the range of analytes that can be measured

has been broadened considerably.

0037 Immunosensors offer a wide range of potential

applications to the food industry, water companies,

and regulatory authorities. In immunosensors or

immunoprobes, the antibody (Ab) or the antigen

(Ag) constitutes the biospecific component in the

sensor structure. A range of immunosensors are being

developed, and with minor adaptations, these can

replace immunoassays. At present, immunodiagnos-

tic tests are used in pollution detection in food

and water samples and also on-farm monitoring of

livestock reproduction (milk progesterone), and

quality control of foodstuffs originating from live-

stock production (authenticity and adulteration

testing). These tests can be developed to a new gener-

ation of rapid immunosensors for real-time and on-

site applications. A range of research projects have

been undertaken to develop immunosensors for resi-

dues in food (antibiotics, toxins, and pesticides), the

presence of additives, and hormones. The availability

of the required antibody can limit the potential for

diverse analyte detection by immunosensors. In-

creased research in the development of specifically

tailored antibodies such as plantibodies produced in

plants, recombinant antibodies, catalytic antibodies

or abzymes, artificial receptors, and molecularly

imprinted polymers should overcome some of these

problems.

0038Immunosensors can be divided into classes

depending on the transducer technology employed.

Electrochemical immunosensors generally rely on the

use of electroactive labels, usually based on enzyme

labeling and amplification techniques. The sensors

can be inexpensive and may achieve low detection

limits (< 1 p.p.b.). Different types of electrochemical

immunosensors and affinity sensors have been de-

veloped for environmental analysis using various

transducers. The scientific literature increasingly con-

tains reports of the development of one-shot dispos-

able or on-line immunosensors for a diverse range of

analytes. However, the technology required to manu-

facture these types of sensors has not yet reached the

level of sophistication achieved for enzyme elec-

trodes, and hence, these devices are at an earlier

stage of commercialization.

0039Optical devices have a clear advantage over elec-

trochemical methods due to their ability to monitor

binding reactions directly. The major drawback to the

application of optics remains the high cost of many

optical components, but these costs are constantly

falling. Optical phenomena such as SPR and evanes-

cent wave (EW) technology have shown promise in

providing direct measurement of Ag–Ab interactions

occurring at the surface–solution interface, the sur-

face usually consisting of a glass prism on a gold or

silver metal layer. SPR is a phenomenon that occurs

when a beam of light is directed on to a glass–metal

interface, which results in changes in the resonance

angle. The BIAcore

biosensor system based on SPR

technology was developed by a Pharmacia (Uppsala,

Sweden) spin-off company and is now commercially

available from Biacore AB (Uppsala, Sweden). This

instrument represents a significant breakthrough in

optical immunosensor technology. BIA technology

enables detection of biomolecules in real time without

the use of labels, but the instruments are expensive

and mainly laboratory-based, and require trained

496 BIOSENSORS

personnel to interpret the results. The Biacore system

has been reported to be able to detect atrazine at

0.05 mgl

1

and E. coli O157 in food samples. Re-

cently, Biacore AB have launched the BIAcore-

Quant

, for the automated analysis of vitamins in

foods (Figure 6). The assay is designed as an inhib-

ition assay, and similar principles are applied for the

determination of drug residues in meat and milk

products using BIACORE 2000. Amersham Inter-

national plc has been active in research into SPR-

based immunosensors for infectious diseases and has

developed immunotechnology that employs anti-

bodies labeled with latex particles (beads). The

beads amplify the change in refractive index at the

sensor surface–solution interface, which occurs when

the antibodies bind to the immobilized antigen layer

and thus cause a large change in the resonance angle.

An alternative direct optical immunosensor to com-

pete with SPR technology has been developed by

Affinity Sensors (Cambridge, UK). The resonant

mirror technology is marketed as the IAsys (IAsys

and IAsys Autoþ) and also enables analysis of bio-

molecular interactions in real-time. Reusable cuvettes

offer a choice of derivatized sensor surfaces and

chemistries. The ligand is simply and efficiently im-

mobilized on to the sensor surface, and binding of the

analyte can be detected immediately.

0040The alternative approach of using fluorecent labels

detected via evanescent wave interactions with an

optical fiber has also been applied successfully. One

example is the Raptor developed by the US Navy

Research Laboratory for the detection of biological

Vitamin-specific molecules are added to sample extract

(a)

(

)

Vitamin-specific

molecule

Vitamin Vitamin sensor

chip

Measurement of unbound

vitamin-specific molecules

Vitamin

concentration

Response (RU)

Sensor chip

fig0006 Figure 6 The BiacoreQuant

surface plasmon resonance system for the automated analysis of foods, (a) the sensor chip, (b) the

procedure. Photo courtesy of Biacore AB.

BIOSENSORS 497

warfare agents. Unilever (Bedfordshire, UK) has de-

veloped a fluorescence-based EW immunosensor that

incorporates a novel capillary-fill design. The system

consists of two glass plates separated by a narrow

capillary gap of * 100 mm. The lower plate acts as

an optical waveguide and contains an immobilized

layer of antibodies on its surface. These sensors bene-

fit from the capillary fill system, which draws a fixed

volume of sample into the space between the plates,

regardless of bulk sample volume.

0041 Piezoelectric transduction approaches and, in par-

ticular, SAW devices have also been widely used to

detect antibody binding to an immobilized antigen.

The most widely used acoustic transducer is the

quartz crystal microbalance, which measures small

changes in surface properties, such as bound surface

mass and viscosity, resulting from the binding of mol-

ecules to the sensor surface. Again, the attraction

of piezoelectric sensors is their ability to monitor

directly the binding of Ab–Ag reaction encountered

in affinity sensing, but they suffer from the disadvan-

tage of having a low sensitivity for small molecules.

0042 Potential areas of application for affinity-based

sensors are similar to those for biocatalytic sensors.

However, affinity sensors can offer enhanced sensitiv-

ity and specificity when compared to biocatalytic

sensors. Commercial immunosensors may not have

been developed specifically for use in the agrofood

and environmental sectors yet, but their long-term

potential is evident. As the commercial success of

immunoassays becomes more evident in health care,

food, and environmental monitoring, the demand for

faster techniques will be sufficient for continued af-

finity sensors development. The development of dis-

posable electrochemical affinity sensors for the rapid

detection of residues of anabolically active illegal

androgens, antibiotics, and other residual compounds

in food samples would allow regulatory bodies to

improve their screening program. A potential market

for immunosensors is genetically modified (GM)

foods testing for protein analysis. Immunoassay tests

as a plate test or dipstick devices for the detection of

GM foods in plant tissues, raw agricultural commod-

ities, and also food ingredients are marketed today by

SDI Europe Ltd. (Hampshire, UK). These types of

tests may well be developed into immunosensors

devices in the near future.

DNA Biosensors

0043 DNA is a double-stranded helical molecule that can

be split into its two complementary strands by treat-

ment with alkali. By using the correct environmental

conditions, the two strands can come together again

(reassociate) in a process that forms the basis of all

DNA hybridization techniques. This technique in-

volves a small quantity of a pure DNA probe that is

labelled and made single-stranded so that it can seek

out and hybridize to its complementary sequence in a

large amount of DNA. The probes can be labelled

with an enzyme marker. Nucleic acids, the building

blocks of DNA and RNA, are universally present in

all living cells and are utilized as a general method of

microbial detection and identification. PCR is a

widely used method for amplifying trace amounts of

DNA for analysis. To date, it has been used mainly for

qualitative analysis, but the need for quantitative in-

formation has resulted in further development of PCR

protocols. Quantitative PCR methods are shown to

be extremely sensitive, and fully automated detection

systems that should be rapid, simple to use, and inex-

pensive are being developed. DNA biosensors are

currently used in the detection of infectious diseases

and genetic abnormalities, where the main approach

has been by the use of immunobased sensors. This

technology is well established, and the performance

of these tests is good. PCR is widely used to amplify

the signal in DNA probes, but it is time-consuming.

There is intense current interest in microsystems for

DNA analysis. An electrochemical DNA sensor based

on a gold electrode modified with DNA probes and

an electroactive hybridization indicator has been

reported in the literature. A range of detection

systems have also been applied in DNA probes such

as the use of enzyme label, an SPR-based biosensor,

an EW biosensor and an acoustic-based sensor.

Affymetrix (Santa Clara, CA) has developed a plat-

form for acquiring, analyzing, and managing com-

plex genetic information. The system is based on

disposable DNA probe arrays (GeneChip) containing

selected gene sequences on a chip, and an instrument

to process each chip, and analyze the information.

This ‘lab-on-a-chip,’ offers traditional, laboratory-

based biological assays in convenient on-site or

on-line instruments. DNA chips are used for micro-

organism identification or detection of GM foods.

The company is developing new chips for microbial

contamination diagnosis in environmental samples.

GeneScan Europe (Hanse Analytik GmbH, Freiburg,

Germany) markets test kits for the detection of gen-

etically modified components in human and animal

foods by DNA analysis using PCR techniques. These

tests can also be developed into DNA biosensor

devices.

Electronic Noses

0044The application of the electronic nose concept or

artificial olfaction has been of tremendous emerging

importance in recent years. Electronic noses are based

498 BIOSENSORS

on the use of artificial receptors in the sensor array,

and their application in food analysis justifies their

inclusion in this article. In recent years, a great deal of

research in the development of the electronic nose has

taken place with a diverse range of applications. This

type of sensor instrument mimics the olfactory system

in the nose. The instrument consists of an array of gas

sensors with different selectivity patterns, a signal

collecting unit, and data analysis software, which

analyses the signal by pattern-recognition methods,

such as principal component analysis, discriminant

function analysis, cluster analysis, and artificial

neural networks. The results are comparative, rather

than quantitative, and are presented as a ‘fingerprint.’

A variety of sensors are used, ranging from metal

oxides to conducting polymers, which can be highly

sensitive but not specific and can respond to volatile

compounds with molecular weight ranging from 30

to 300. Molecules such as alcohols, ketones, fatty

acids, and esters give a strong response, whereas

fully oxidized species, such as CO

,NO

, and H

have a lower response. The sensor array can also

recognize molecules containing sulfur and amine

groups. Furthermore, they are not in direct contact

with the measuring media, since they are used for gas-

phase measurements.

0045 There has always been considerable waste during

the storage and handling of food. Moreover, food

often constitutes an ideal growth medium for micro-

organisms. The composition of volatile compounds

evolved from the food can reflect the activity and type

of microorganisms present and also can be related to

food quality. Thus, electronic noses appear to be a

useful means of detecting these kinds of changes.

Electronic noses have been used in medical, environ-

mental, and food diagnoses. The majority of the

current research concentrates on quality control in

the foods and drinks industry, such as the detection

of microbial contamination (bacteria, fungi, and

yeast), freshness of meat and fish, and authenticity

(beverages, coffee, and meat).

Conclusions

0046 The food and drink industry deals with a wide range

of materials and products with different characteris-

tics and diverse processing procedures. The shared

theme, however, is that the raw materials are organic,

subject to environmental pollution, degradations

and microbial contamination. The food diagnostics

market is expanding rapidly and covers a wide range

of disciplines. The establishment of appropriate tech-

nologies to apply biosensors to practical agriculture

and horticulture is expected to produce a significant

effect on quality improvement and cost reduction.

Biosensor applications in the medical diagnostics

market have been highly successful, but their poten-

tial success in the food, agriculture, veterinary diag-

nosis, and environmental market still remains to be

established. Biosensor systems, which are relatively

small portable instruments, have an on-site applica-

tion, and their relatively low cost is clearly desirable

in agrofood analysis. Research is being undertaken in

diagnostic companies and research institutions to

develop biosensor technologies for the food and en-

vironmental sector. Nevertheless, moving the technol-

ogy to the market place involves many challenges.

Biosensors will have to offer perceived advantages

over existing and competing technologies.

See also: Enzymes: Functions and Characteristics;

Nucleic Acids: Properties and Determination;

Genetically Modified Foods.

Further Reading

Cunningham AJ (ed.) (1998) Introduction to Bioanalytical

Sensors. New York: Wiley-Interscience.

Fellows PJ (ed.) (1996) Food Processing Technology,

Principles and Practice, Series in Food Science and

Technology. Cambridge: Woodhead.

Kress-Rogers E (ed.) Handbook of Biosensors & Electronic

Noses. Boca Raton, FL: CRC Press.

Mathewson PR and Finley JW (eds) (1992) Biosensors

Design and Application, ACS Symposium Series 511.

Washington, DC: American Chemical Society.

Mulchandani A and Rogers KM (eds) (1998) Methods in

Biotechnology; Enzyme and Microbial Biosensors.

Techniques and Protocols. Totowa, NJ: Humana Press.

Rogers KR and Mulchandani A (eds) (1998) Methods in

Biotechnology 7, Affinity Biosensors, Techniques and

Protocols. Totowa, NJ: Humana Press.

Scott AO (ed.) (1998) Biosensors for Food Analysis. Cam-

bridge: The Royal Society of Chemistry.

Turner APF (ed.) Advances in Biosensors. volumes 1; 2;

Suppl 1; 3; 4 (1991; 1992; 1993; 1995; 1998). London/

Amsterdam: JAI Press/Elsevier.

Turner APF (2000) Biosensors McGraw Hill Yearbook of

Science and Technology 2000. New York: McGraw Hill.

Turner APF, Karube I and Wilson GS (eds) (1989) Biosen-

sors: Fundamentals and Applications. Oxford: Oxford

University Press.

BIOSENSORS 499

BIOTECHNOLOGY IN FOOD PRODUCTION

SPe

rez-Magarin

o and M L Gonza

lez-Sanjose

University of Burgos, Burgos, Spain

Introduction

0001 Biotechnology’s origins lie in the ancient crafts of

brewing, baking, and the production of fermented

foods such as yogurt and cheese, although it was

not until 1859 that microorganisms were identi-

fied as the cause of both desirable and undesirable

changes in food. During the 1940s, microorgan-

isms, as submerged cultures in large vessels, were

developed. Nowadays, similar fermentation tech-

nology is applied to obtain a wide range of bio-

products.

0002 In the 1950s, the primary structure of proteins and

DNA was first determined. These discoveries led to

the development of molecular biology in the 1960s

and genetic engineering techniques in the 1970s.

Techniques developed using microorganisms have

been applied to plants and animals, and these trans-

genic plants and animals have been produced to make

many useful products.

0003 For centuries, humans have been selecting, sowing,

and harvesting seeds to produce better food more

efficiently. In recent decades, global food demand

has increased enormously, and biotechnology has

offered the technology required to produce more

nutritious and better-tasting foods, higher crop

yields, and plants protected against disease and

insects.

Definition of Biotechnology

0004 The term ‘biotechnology’ has come to mean different

things to different people. In general, biotechnology is

the integration of natural sciences and engineering in

order to provide new products and services by the

application of organisms, cells, parts thereof, and

molecular analogs.

0005 In a broad sense, biotechnology covers many of the

tools and techniques that are commonplace in agri-

culture and food production. However, in a narrow

sense, biotechnology considers only the new DNA

techniques, molecular biology, and reproductive

technological applications. Thus, ‘biotechnology’ for

many people refers specifically to the genetic engin-

eering techniques that have been developed in the last

30 years.

Food Biotechnology

0006Biotechnology provides powerful tools for the sus-

tainable development of agriculture as well as the

food industry, improving the production of foods

and making them more available and nutritious.

Food biotechnology is a rapidly expanding field of

science with many different applications, which is

clear from the large number of scientific papers pub-

lished in the last 10 years. The Food Science and

Technology Abstracts (FSTA) database reveals at

least 4150 articles on Food Biotechnology published

between 1990 and 2000, which represents almost

4% of the number of total published papers on food.

0007According to FSTA information and the current

situation of the food industry, some of the main

areas of application of food biotechnology are: the

production of new kinds of foods and drinks, both by

modern developments of conventional techniques

and by genetically modifying the products them-

selves, or producing them using genetically modified

(GM) organisms or their products.

0008The majority of articles deal with fermentation

processes, the use of enzymes and microorganisms

(Figure 1). These fields have been the most important

and traditional applications of biotechnology in food

production. However, in the last few years, investi-

gations into genetic engineering, molecular biology,

and cell cultures have been increasing significantly.

Traditional Food Biotechnology

0009Traditional biotechnology refers to the conventional

techniques that have been used for many centuries to

produce beer, wine, cheese, bread, and other foods,

all of them foods obtained by fermentation processes.

0010The fermentation of food is the oldest biotechno-

logical process, and is the oldest form of food preser-

vation. In brief, fermentation is anaerobic conversion

of certain carbohydrates (such as reducing sugars,

mainly glucose) to other products such as:

0011alcohol, glycerol and carbon dioxide, the principal

products of the fermentation of yeast sugars (alco-

holic fermentation);

0012butyl alcohol, acetone, lactic acid, and acetic acid,

the principal products of bacterial action (such as

acetic, lactic, and malolactic fermentation).

Of the many possible types of fermentation processes,

lactic acid fermentation and alcohol fermentation are

the two most common. These processes are carried

out by specific microorganisms (several yeasts and

500 BIOTECHNOLOGY IN FOOD PRODUCTION

bacteria), and they are regulated by the action of

specific enzymes.

0013 Traditional biotechnology is most closely related to

food production both in the selective breeding of food

plants and animals and in food processing using

microbial enzymes. Traditional selection techniques

have been employed to develop a great variety of

plants, animals, and microorganisms for the produc-

tion of a wide range of food products and ingredients

for processed foods.

0014 In addition, enzymes have been applied to practical

uses for thousands of years, in the form of crude

animal or plant preparations or as a consequence of

permitted microbial development. Improvements in

modern techniques, which allow purification and

purification of specific fungal and microbial enzymes

and their production at an industrial level, has made

it possible to use enzymes in order to facilitate and

improve some food manufacturing processes.

0015 Current technology for dealing with complex or-

ganisms advances modern biology and permits us to

understand many traditional processes in which bio-

logical agents are involved, allowing the application

of new fermentation and enzyme technological pro-

cesses to food production. This new situation has

opened the doors to an exciting dimension of food

biotechnology, which has been called ‘modern food

biotechnology.’

Modern Food Biotechnology

0016 Modern biotechnology embraces all methods of

genetic modification by recombinant DNA and

cell-fusion techniques together with the modern

developments of ‘traditional’ food biotechnological

processes. Genetic modification techniques (GMT)

are now being used in the production of new foods

and drinks. Genetic modification involves the inser-

tion of one or a small number of scientifically well-

characterized genes into the food plant, animal,

or microorganism. These techniques will play an

increasingly useful and economic role, and they are

strongly related to fields such as genetic engineering,

molecular biology, protein engineering, biochemical

engineering, and processes involving monoclonal

antibodies, which are beginning to have a consider-

able impact on food processing.

0017Modern biotechnology will pursue not only the

production of new foods but also the preservation of

raw materials, increased shelf-life of final products,

and the planned alteration of their nutritional and

functional properties. It also affects the development

of processing aids and direct additives that can

improve the overall utilization of materials. GMT

are being used to achieve many of the same aims as

traditional breeding and selection methods but have

at least two main advantages. First, they provide the

means of controlling the introduction of genes with

much greater prediction and precision than can be

achieved by traditional methods. Second, they make

it possible to introduce copies of genetic material into

unrelated species hitherto impossible to achieve by

traditional techniques.

0018Some applications of genetic engineering tech-

niques are:

0019increasing the resistance of plants to diseases and

pests, herbicides or pesticides;

0020developing plants to withstand more extreme

environmental conditions (drought, frost, and soil

salinity, amongst others);

0021developing foods with specific properties and im-

proved quality (sensorial and nutritional character-

istics);

0022adapting microorganisms for more efficient food

production and to produce natural food ingredients

(amino acids, organic acids, volatile fatty acids,

vitamins, etc.);

0023obtaining enzymes, antibodies and microorgan-

isms to monitor food production and processing

Fermentation

Enzymes

Microorganisms

Genetic engineering

Molecular biology

Cell cultures

Other

17%

23%

26%

19%

fig0001 Figure 1 Percentage of published papers on different fields of biotechnology in food production.

BIOTECHNOLOGY IN FOOD PRODUCTION 501

systems for quality control. Microbial probes and

biosensors are being used experimentally as indica-

tors of bacterial and other types of contamination;

and

0024 improving animal farming by genetic modification

of crop plants for animal feed, of microorganisms

or enzymes to improve the nutritional value of

animal food stuffs and in the animal health sector

for pharmaceuticals.

Benefits and Risks of Food Biotechnology

0025 For centuries, farmers have relied on the newest tech-

nology to produce and enhance foods that possess

specific beneficial traits. The use of biotechnology

benefits not only the grower or producer but also

the consumer.

0026 The current benefits of biotechnology include dis-

ease resistance, reduced pesticide use, herbicide toler-

ance, more rapid growth of crops, producing higher

yields. Hence, biotechnology benefits the environ-

ment, including water and soil conservation, and is

safer for workers and the ecosystem. Also, it can

enhance the nutritional characteristics of foods and

improve food taste and quality.

0027 Biotechnology has been used in a number of crops

for several years. The volume of biotechnological

crops in developmental stages continues to grow. In

the early 1990s, many people were skeptical that

transgenic crops could provide improved products.

During the last five years, the planting of transgenic

crops has increased, thus demonstrating that the early

promises of transgenic crops are meeting the expect-

ations of farmers of both large and small farms

planting these crops in both industrial and developing

countries. However, two-thirds of total transgenic

crops are in the developing countries, where yields

are lower, and the need for improved production of

food is the greatest.

0028 More genetically enhanced products are expected

to be on the market in the years to come, many of

which are similar in nature to products already on the

market. Benefits that can be expected in the near

future include:

0029 reduced levels of natural toxins in plants;

0030 simpler and faster methods to locate pathogens,

toxins, and contaminants; and

0031 extending the time before spoilage.

The world population is expected to double by the

year 2050. Few other new technologies will be able to

approach biotechnology’s potential to help avoid

starvation in the next century. Another economic

and environmental benefit is in the area of fertilizer

use. Much of the fertilizer used is wasted and can end

up in water sources, damaging the environment.

Some plants, such as corn, might also be modified to

draw nitrogen from the soil, thereby reducing the

need for fertilizer. Benefits that can be expected fur-

ther down the road include:

0032producing safer foods through reduction of aller-

genic proteins;

0033drought and flood tolerance;

0034salt and metal tolerance; and

0035heat and cold tolerance.

In general, according to most scientific papers pub-

lished, the use of biotechnology poses no specific risk,

and products should not be discriminated against on

the grounds of their method of production. The sci-

entific consensus is that the risks associated with food

biotechnology are fundamentally the same as for

other foods. Current science shows that foods made

using biotechnology are safe to consume and safe for

the environment. Although there is no such thing as

‘zero risk’ for any food, consumers can be confident

that foods produced using biotechnology meet the

government’s most stringent food-safety standards.

Years of research and no evidence of promoting

health harm indicate that the benefits of agricultural

biotechnology far outweigh any risks.

0036However, there are people, amongst them ecolo-

gists and activist groups, who do not agree with this.

Some of their arguments against biotechnology are

that the use of GM products could reduce genetic

diversity indirectly if, for example, farmers adopt

genetically uniform varieties of plants and other

organisms. The inclusion of novel genes for herbicide

resistance in plants may increase the occurrence

of weeds with resistance to certain agrochemicals.

Others are concerned about the possible appearance

of allergens or toxins and possible causes of different

human diseases.

0037Thus, despite the benefits to be gained from modern

biotechnology, the products obtained need to have

appropriate legislation and safeguards to protect

human health and the environment.

Current Concerns, Regulations, and

Labeling

0038According to the concerns expressed about the pos-

sible existence of health hazards associated with the

consumption of food containing modified genetic

material, it is clear that rational policies are needed,

regarding the regulatory status of bioengineering

products.

0039Studies about public perceptions, consumer atti-

tudes, and ethical implications of biotechnology in

food and drink production have shown that certain

502 BIOTECHNOLOGY IN FOOD PRODUCTION

applications are more acceptable than others. For

example, according to the European Federation of

Biotechnology, the use of biotechnology to change

plants was considered more acceptable than using it

to change animals. In addition, around 85% of inter-

viewees said that food obtained with genetic tech-

niques should be clearly labeled. It will be necessary,

therefore, to develop programs to educate the public

about the benefits and problems of biotechnology in

the production and processing of food. Governments

and scientific institutions must be encouraged to

share knowledge on transgenic foods with society,

such that people are well informed about the impact

of biotechnology on the environment, food safety,

sustainability, and global food safety. In addition, as

with any technology, there are limits that will and

must be subjected to law. Countries must be helped

to develop appropriate legislation and to set up

proper regulatory bodies for all aspects of biosafety.

Appropriate regulation is a prerequisite from the

point of view of both the general public and the

food industry.

0040 In the USA, there are three organizations respon-

sible for controlling GM organisms and products.

The Environmental Protection Agency (EPA) and

the United States Department of Agriculture (USDA)

oversee the effects of GM organisms on the environ-

ment and on plant production. The Food and Drug

Administration (FDA) is responsible for overseeing

the safety of food, which is determined by the charac-

teristics of the consumed or processed product rather

than the method by which it was produced. The FDA

policy statement also addresses the labeling of foods

obtained from new plant varieties. It states that label-

ing is only required when a food obtained from a GM

variety differs from that obtained from a conven-

tional counterpart.

0041 Nowadays, in Europe, there is no equivalent over-

all agency for food regulation, although a European

Institute will be in operation in the near future. Until

this time, the European Commission has therefore

proposed harmonizing regulation between member

states. The Council of the European Community

(EC) adopted the Directive 90/220/EC on the deliber-

ate release into the environment of GM organisms.

This directive had two main objectives: to protect

human health and the environment and to provide a

harmonized regulatory framework of GM organisms

with the EC.

0042 In the EC, the safety of GM foods is controlled by

Regulation (EC) No. 258/97 concerning novel foods

and novel food ingredients, and the labeling of GM

foods is regulated by two regulations, with important

differences with American Regulations. First, Com-

mission Regulation (EC) No. 49/2000 establishes that

the foodstuffs shall not be subject to the additional

specific labeling requirements when the material de-

rived from the GM organisms is present in a propor-

tion no higher than 1% of the food ingredients

individually considered or food comprising a single

ingredient, or this presence is adventitious. Second,

Commission Regulation (EC) No. 50/2000 estab-

lishes the labeling of foodstuffs and food ingredients

containing additives and flavorings that have been

genetically modified or have been produced from

GM organisms. In addition, novel foods and GM

foods also have to fulfill the general labeling require-

ments set out in the Directive 2000/13/EC, which

deals with an approximation of the laws of the

Member States relating to the labeling, presentation,

and advertising of foodstuffs.

0043With so many foods traded internationally, there is

a clear need to reach a harmonized approach to label-

ing GM foods if potential trade barriers are to be

eliminated. Therefore, it will be necessary to develop

international safety guidelines.

0044In 1990, Food and Agriculture Organization (FAO)

and the World Health Organization (WHO) took the

first steps towards international harmonization of the

food safety assessment of GM foods. It was recom-

mended that the safety assessment of foods produced

by biotechnology should take into account the mo-

lecular, biological, and chemical characteristics of

these foods. The 1996 FAO/WHO report defined

substantial equivalence as ‘established by a demon-

stration that if the characteristics assessed for the GM

organisms, or the specific food product derived there-

from, are equivalent to the same characteristics of the

conventional food, then it can be assumed that the

new food is as safe as the conventional equivalent.’ In

1999, the FAO/WHO of Codex Alimentarius estab-

lished the Codex Ad Hoc Intergovernmental Task

Force on Foods derived from Biotechnology to elab-

orate norms and guidelines for the foods derived from

biotechnology. The Task Force held its first session in

March 2000, and approved the elaboration of major

texts with a set of broad general principles for risk

analysis and specific guidance on the risk assessment

of foods derived from biotechnology. It will also have

to prepare a list of available analytical methods in-

cluding those for the detection or identification of

these kinds of foods.

0045The Task Force agreed that the labeling was

covered by the Codex Committee on Food Labeling,

and the environmental risk was addressed by other

bodies such as the Cartagena Biosafety Protocol

under the Convention on Biological Diversity, the

International Plant Protection Convention, and the

Commission on Genetic Resources for Food and

Agriculture.

BIOTECHNOLOGY IN FOOD PRODUCTION 503

Biotechnology in the Food Industry

0046 As we said earlier, biotechnology applied to food

production has a long history, beginning in cottage

industries such as bread-making, cheese-making, and

brewing. Many biotechnology advances have been

made in the food industry over the last century. A

major advance has been in food preservation, which

is basically the prevention of undesirable microbial

and enzyme activity in foodstuffs. This allows the

storage of food over much longer periods and permits

transport over great distances. The development of

genetic techniques also represents a great advance,

providing opportunities for much innovation.

0047 According to the data obtained from the FSTA data

base (Figure 2), food biotechnology processes are

applied more to manufacturing foods of vegetable

origin (38%) than to foods of animal origin (26%).

In addition, the fields of study covered by the two

largest groups of papers were vegetables and fruits

first (19%) with dairy products in second place

(15%). Papers on beverages, cereal products, meat

products and fish products have been published

more or less in the same quantity. During the last

few years, the most frequent applications of biotech-

nology in food industries have been as follows.

Biotechnology in the Vegetable and Fruit Industries

0048 Enzyme applications are very common in this indus-

try. The presence of acid phenols and tannins in fruits

has been studied, owing to their effect on bacterial

growth during lactic fermentation.

0049 Pectinolytic enzymes and cellulolytic enzymes are

the most commonly used. These enzymes have appli-

cations in plant tissue maceration and in fruit juice

processing, improving the clarification of juices and

manufacturing processes of fruit such as peeling.

Owing to the importance of these enzymes, many

works have studied their activities during the ripening

of fruits. These enzymes have even been extracted

from fruits and purified later to be characterized

and applied in different food industries.

0050Vegetables and fruits are used as substrates in some

reactions, owing to their enzymatic systems, to

produce other chemical compounds, such as volatile

flavor compounds, lipids, vitamins, enzymes, pig-

ments, etc.

0051The genetic variation of some vegetable and fruit

crops, and the effect of genotype and environment

on yield and quality, have been investigated, using

random amplified polymorphic DNA. This DNA-

based technology and others have resulted in a sub-

stantial increase in the number of genes identified and

characterized, which will make it possible to produce

transgenic crops of several vegetables and fruits.

Biotechnology in the Beverage Industries

0052In general, fermented beverages are obtained by the

presence of determinate microorganisms, so the

majority of published papers deal with this topic.

0053Many applications focus on the selection of yeasts

capable of performing alcoholic fermentation under

extreme conditions (high sugar concentration, high

amounts of SO

or ethanol). GM amylolytic yeasts,

which can hydrolyze starch, have been used to

improve fermentation processes.

0054Some studies on the evaluation of the use of non-

Saccharomyces yeasts, separating those that could

positively affect the taste and flavor of alcoholic

beverages from others that produce large amounts

of negative byproducts, have also been developed.

Yeasts selected have been applied to obtain fruit

drinks with a slightly acid and less sugary taste. The

use of immobilized cells in fermented beverages for

continuous production has also been studied.

0055Another field is the use of different methods such as

the combination of pressure, heat, and bacteriocins,

and a flow-through photoreactor, to render inactive

foodborne pathogens in some juices and some micro-

organisms in water, respectively.

0056Other studies have investigated the molecular and

catalytic properties of different types of enzymes

(proteinases, glucosidases), which have particular

Dairy

Meat

Fish

Vegetables & fruits

Cereals

Beverages

Others

10%

19%

15%

36%

fig0002 Figure 2 Percentage of food biotechnology published papers in different sorts of food industries.

504 BIOTECHNOLOGY IN FOOD PRODUCTION