Archive-Name: sci/food-science-faq/part3
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Last-modified: 2012/08/11
RE-POST: FAQ Section 3/3 - SCI.BIO.FOOD-SCIENCE Frequently-Asked Questions
See the first section (1/3) of this FAQ for any preliminary and
introductory remarks. See this section also for a list of food science
related sites and abbreviations.
For a list of definitions of industry, marketing, and scientific terms in
food science, see section 2/3 of the FAQ.
*************************************************************************** **
V. FREQUENTLY ASKED QUESTIONS ABOUT FOOD SCIENCE AND TECHNOLOGY
Here are brief answers, compiled by the Institute of Food
Science & Technology, to some of the most frequently asked questions
about food science and technology topics. Food scientists and
technologists will appreciate that, because they are brief, and
because they are intentionally written so as to be comprehensible to
enquiring non-scientists readers of the newsgroup, they will not
adequately fulfil the requirements of a scientist looking for a full
"textbook" account.
The Institute of Food Science & Technology (IFST) is the
independent non-profit professional qualifying body for food
scientist and technologists, a UK-based body with international
interests. Its home page on the World Wide Web is at
http://www.easynet.co.uk/ifst/
KEY DEFINITIONS
Food science --
is a coherent and systematic body of knowledge and understanding
of the nature and composition of food materials, and their behaviour
under the various conditions to which they may be subject.
Food technology --
is the application of food science to the practical treatment of
food materials so as to convert them into food products of the kind,
quality and stability, and so packaged and distributed, as to meet
the needs of consumers for safe, wholesome nutritious and attractive
foods.
*****
Thus, food science integrates the application to food of several
contributory sciences. It involves knowledge of the chemical
composition of food materials (for all food consists entirely of
chemical substances); their physical, biological and biochemical
behaviour; human nutritional requirements and the nutritional factors
in food materials; the nature and behaviour of enzymes; the
microbiology of foods; the interaction of food components with each
other, with atmospheric oxygen, with additives and contaminants, and
with packaging materials; pharmacology and toxicology of food
materials, additives and contaminants; the effects of various
manufacturing operations, processes and storage conditions; and the
use of statistics for designing experimental work and evaluating the
results.
Likewise, food technology draws on, and integrates the
application to food of, other technologies such as those of steel,
tinplate, glass, aluminium, plastics, engineering, instrumentation,
electronics, agriculture and biotechnology.
FAQ GROUPINGS
In the interests of "user-friendliness" the FAQ is written so
that, as far as possible each answer is self-contained. This of
necessity results in some repetition of material in the answers to
related question For convenience, the FAQs are in four Groups as
follows:
GROUP 1 FOOD AND NUTRITION
GROUP 2 FOOD SAFETY
GROUP 3 ADDITIVES AND PACKAGING
GROUP 4 SCIENCE AND FOOD
The following is a summary of the questions, by the grouping
described above. The group answers can be found under headings of the
format: "ANSWERS TO GROUP [number] QUESTIONS - [group name]",
excluding the quotes and square brackets, and all capital letters.
When the answer to a question is given, the question and question
number will be repeated in the line above it.
GROUP 1 -- FOOD AND NUTRITION
1.What is good/bad food?
2.What is a good diet?
3.Do I need to worry about getting enough protein?
4.Is sugar harmful?
5.Isn't honey healthier than sugar?
6.Why is sugar used in foods?
7.Is salt harmful?
8.Why is salt used in foods?
9.Are fats harmful?
10.What about different types of fat?
11.Should we cut out all fats?
12.What is a hydrogenated vegetable oil?
13.What are trans fatty acids?
14.What are low-density lipoproteins?
15.Is margarine better for us than butter?
16.Aren't natural foods better for us than processed foods?
17.Why are foods processed?
18.Is a vegetarian diet better for us?
19.Isn't it more expensive to eat a 'prudent' diet?
20.Do we need more vitamins and minerals?
21.Do organic foods taste better?
22.What foods are good for arthritis?
23.Is ginseng/royal jelly/pollen/lecithin/kelp good for me?
24.What are 'junk foods'?
GROUP 2 -- FOOD SAFETY
1.What is food poisoning?
2.Why has food poisoning increased so much?
3.Why all the fuss about food hygiene?
4.Aren't we losing natural immunity by producing foods with no
pathogens present?
5.How can food poisoning be prevented?
6.What about irradiation of food?
7.Isn't genetic modification a dangerous interference with nature?
8.Doesn't gene transfer from one species to another create the
risk of ethical problems or even cannibalism?
9.Shouldn't all genetically modified foods, or those containing
genetically modified ingredients, be labelled as such, to warn
consumers?
10.With regard to BSE, is British beef safe to eat?
GROUP 3 -- ADDITIVES AND PACKAGING
1.Why are food additives used?
2.But aren't additives dangerous?
3.Food colours are only cosmetic -- shouldn't they be banned?
4.Why are foods packaged?
5.What function does packaging perform?
6.Do we really need the protection that packaging is said to
provide?
7.Is packaging wasteful of materials and energy?
8.Can packaging and energy usage be reduced without compromising
the protection it gives to the food?
9.Why are there so many different types of packaging materials?
10.Why are some packages difficult to open?
11.What about recycling of packaging?
12.What about returnable, refillable systems?
13.Why does packaging contribute so much to household waste?
14.Do packaging materials affect the food in them?
GROUP 4 -- SCIENCE AND FOOD
1.What is food science? What is food technology?
2.Wouldn't our food be even better without scientists and technologists
interfering with it?
3.Why do scientific experts often disagree?
4.Doesn't hindsight show that the experts always "got it wrong"?
ANSWERS TO GROUP 1 QUESTIONS - FOOD AND NUTRITION
***************************
1.What is good/bad food?
In keeping with their Code of Professional Conduct, food
technologists in industry take great care to ensure that food
products are safe and wholesome. But eating or drinking too much of
any food can be bad for you -- too much water can kill you. We
shouldn't think of good foods or bad foods, but of good or bad diets.
2.What is a good diet?
A good diet is a balanced one; lots of different foods and not
too much of any one food. That way you get all the nutrients that you
need. Many countries have guidelines for healthy diets, including in
some cases recommended daily amounts of specific nutrients. However,
it is emphasised that these are for healthy individuals, not for
those with disease symptoms, food allergies, or intolerances. These
people should consult a dietitian or physician.
3.Do I need to worry about getting enough protein?
You will automatically get enough protein to stay healthy if you
eat a varied diet and sufficient of the wide range of foods available
to stop you feeling hungry.
4.Is sugar harmful?
Not in itself. However, if you eat a lot of sugar in the form of
sweets (candy), you may not eat enough of all the other foods needed
to provide your body with the nourishment it needs. Sugar can cause
dental decay if you eat sweets or drink sugar-sweetened drinks
between meals. You need to clean your teeth afterwards in the
conventional way or by eating a piece of cheese. Otherwise the sugar
sticks to your teeth causing plaque and decay.
5.Isn't honey healthier than sugar?
Not really. Honey is largely a strong solution of sugars called
fructose and glucose, which affect teeth only very slightly less than
ordinary sugar (sucrose). There is nothing specially healthy about
honey. The traces of micronutrients it contains are too small to make
any significant contribution to our diet.
6.Why is sugar used in foods?
Sugar is used in some foods to make them sweet, in others in
small quantities to enhance the flavour but not enough to make them
sweet. In some foods, however, sugar is an essential part of the
structure and recipe; for example in cakes or biscuits (cookies).
7.Is salt harmful?
Salt is essential to a healthy diet. We need about 1 g of salt a
day. However, many of us consume about 10 g a day, ten times as much
as we really need. A single dose of ten times that amount could be
fatal! There is evidence that, for some people, too much salt can be
a contributory factor to high blood pressure. Just how much is 'too
much' varies from person to person. Prudent advice would be to reduce
consumption to around 5 g per day.
8.Why is salt used in foods?
There is enough salt naturally present in food to satisfy our
daily 1 g need. However, salt is sometimes added during processing or
cooking of food, and is also often sprinkled on a meal by consumers
to enhance and improve the taste and flavour. Bread, tomatoes, boiled
eggs do not taste good enough for many people unless salt is added.
It is also used to preserve some foods. Salt curing is one of the
earliest known forms of food preservation.
9.Are fats harmful?
As with everything else, but more importantly with fats, too
much is harmful. Many common diseases such as heart disease are
linked to high consumption of fats, more especially saturated fats --
the type mostly found in animal fat.
10.What about different types of fat?
Fats in foods, or, more correctly, their fatty acids, are of
three main types, saturated, monounsaturated and polyunsaturated.
Saturated fatty acids carry a full quota of hydrogen atoms in
their chemical structure. This is the type that increases the amount
of cholesterol in the blood and is considered a risk factor in heart
disease; animal fats are the main source.
When one pair of hydrogen atoms is missing, the fatty acids are
termed monounsaturated. They do not raise blood cholesterol and may
even be beneficial. The main sources are olive oil and rapeseed oil
(used in some margarines and low fat spreads).
When more than one pair of hydrogen atoms is missing, the fatty
acids are termed polyunsaturated. They predominate in most vegetable
oils. Most appear to have no effect on blood cholesterol levels but
are useful if they replace saturates in the diet. However, those
found in fatty fish and fish oils (termed omega-3 polyunsaturated)
are considered to help to lower cholesterol and therefore to be
beneficial.
11.Should we cut out all fats?
No, because some fatty acids are essential, and we need a
certain amount of fat in the diet to be able to absorb the
fat-soluble vitamins. Compared with an average Western diet, a
prudent diet would contain a reduced intake of total fat, and, within
that, a lower proportion of saturated fat and a higher proportion of
mono- and polyunsaturated fats.
12.What is a hydrogenated vegetable oil?
Vegetable oils, as the name implies, are liquid at room
temperature. To make them suitable for use in margarines and
shortenings, they are hydrogenated, i.e. treated with hydrogen, to
solidify them. The hydrogenation process makes them more saturated.
13.What are trans fatty acids?
Unsaturated fatty acids in foods can exist in two
differently-shaped forms, scientifically described as the cis and
trans forms. Some trans fatty acids are naturally found in milk and
butter. When oils are hydrogenated, the unsaturated fatty acids
become partially-saturated though retaining a degree of unsaturation.
In the course of this, these still partially-unsaturated fatty acids
have, to some extent, become converted to the trans form. Research
has now been convincing enough to cause the United States Department
of Agriculture (USDA) to issue a warning regarding trans fats.
According to the USDA website, trans fats tend to raise the level of
low-density lipoproteins (LDLs) in the blood when taken in combination
with saturated fats and dietary cholesterol. The USDA recommends
cutting back on saturated fats, cholesterol, and trans fats to reduce
the risk of heart disease.
14.What are low-density liproproteins?
All lipoproteins are produced entirely inside the body as a result of
digestion, so attention will be given to aspects of lipoproteins
having to do with our diet. Fats are packaged in the intestine inside
of cell membrane material called chylomicrons. These consist of
triglycerides and cholesterol packed inside a wrapper of phospholipid
and protein. These chylomicrons travel to parts of the body so that
the fat inside them can be deposited to other cells. What is left is
sent to the liver for recycling.
In the liver, the triglycerides are used to make many different
molecules, including cholesterol, which can be produced from
excess faty acids. Phospholipids, triglycerides, and cholesterol are
sent out of the liver in the form of "very low-density lipoproteins",
or VLDL. This gives the cells of the body a second chance at
absorbing fats, plus whatever other compounds the cells need.
Triglycerides get absorbed faster than cholesterol, and as a result
get denser, and are called LDLs, or "Low-density lipoproteins".
LDLs are almost 50% cholesterol, making them a prime cause of
atherosclerosis (hardening of the arteries) if in excess in the
blood. Since cholesterol can be produced by any fatty acid, "cutting
back on cholesterol" means by extension, cutting back on ALL dietary
fat. Ironically, dietary cholesterol is less harmful, since cholesterol
must be broken down before it is absorbed into the intestinal wall.
On the other hand, if the food contains a lot cholesterol, it will
generally contain other fats as well, usually in even greater amounts.
Foods high in cholesterol are generally from animal sources, and
therefore are usually high in other fats.
Reducing risk of heart ailments means reducing the prescence of LDLs
in the blood. This may be done in several ways, involving dieting,
excercise, or preferably both.
15.Is margarine better for us than butter?
There is no simple answer. Butter contains more saturated fatty
acids than margarine, but less trans fatty acids than some
margarines.
16.Aren't natural foods better for us than processed foods?
Nearly everything we eat comes originally from a natural source,
but much of it is processed to preserve it so that it keeps better
(e.g. canned, frozen or chilled foods); or to make it easier to eat
(like wholemeal bread, a highly processed food made from wheat); or
to make it safer (like milk that is pasteurised).
There is no simple answer to the question. In some instances
processed food is better for us, for example because harmful
substances naturally present have been removed or destroyed during
processing, or because the food has been enriched with nutrients. In
many instances there is no difference. It could be argued that, taken
in isolation, an apple for dessert is better for you than a chunk of
Black Forest Gateau covered in cream; but even in the healthiest diet,
there is room for an occasional indulgence.
17.Why are foods processed?
To make them palatable, edible, convenient and with suitable
keeping properties, Processing also adds variety to the diet by
making foods from combinations of ingredients, as cooks have done
down the ages.
18.Is a vegetarian diet better for us?
Not necessarily. Current nutritional advice, to eat less fat,
more fibre, more fresh fruit and vegetables and more starchy foods,
may indeed be easier to achieve with a vegetarian diet. However,
animal foods provide a concentrated source of protein, vitamins and
minerals. These nutrients can be obtained from a vegetarian diet, but,
unless it is expertly-designed, there could be difficulties with
protein quality and with some micro-nutrients, especially with
calcium and vitamin B2 (riboflavin) if milk products are rejected.
[Note: Whereas vegans are very well informed about problems of
obtaining sufficient vitamin B12 in a vegan diet, and there are
numerous yeast-based spreads and supplements for their use, no
warning is given anywhere in vegetarian/vegan literature about
vitamin B2. In a typical western diet, some 40 per cent of the
vitamin B2 intake derives from milk products. Someone switching to a
vegan or strict vegetarian diet that excludes milk products will not
only lose a major source of calcium, but will (in most cases,
unknowingly) lose that 40% of vitamin B2. That is why we rectify that
information deficiency in this FAQ, so that the deficits can be made
up from other sources].
There is an increase in the number of people who are vegetarian;
either because they are concerned about animal welfare, especially of
farm animals, and do not wish to eat meat or animal products, or
because they believe that there are health benefits in following a
vegetarian diet. The Vegetarian Society provides a wealth of
vegetarian nutrition information to help ensure the nutritional
adequacy of such diets.
19.Isn't it more expensive to eat a 'prudent' diet?
Eating more fruit and vegetables and less fat does at first
sight cost more, and needs more careful selection of foods. On the
other hand, if these 'prudent diet' foods are replacing prepared
convenience foods and fatty-sugary desserts, there may actually be a
cost-saving.
20.Do we need more vitamins and minerals?
A balanced and varied diet -- not too much of anything -- will
normally supply enough from a nutrition point of view. There may be
problems for children, adolescents, the elderly, women during
pregnancy and lactation, and people on slimming diets. These people
would probably benefit from a vitamin and mineral supplement. There
is also increasing evidence that certain vitamins (i.e. vitamins C
and E) have additional beneficial properties as antioxidants.
21.Do organic foods taste better?
Some people who favour organic foods for other reasons claim
that they taste better; but there is so much flavour variation among
different varieties, different degrees of ripeness or freshness or
length of storage of the same fruit or vegetable, that it is very
difficult for individuals to make true comparisons.
Generally, when attempts have been made to carry out
scientifically-designed blind tasting tests on the same variety,
organic versus non-organic, taste panels have been unable to detect a
flavour difference.
22.What foods are good for arthritis?
No individual foods will positively help disorders of this kind,
although there is some evidence that a diet low in saturated fats and
high in polyunsaturated fatty acids (particularly the omega-3
polyunsaturated fatty acids) could benefit sufferers. Although there
are various anecdotal claims about benefit from avoiding certain
foods, there is little or no scientific evidence to support them.
23.Is ginseng/royal jelly/pollen/lecithin/kelp good for me?
No convincing scientific evidence has so far been forthcoming to
substantiate claims for any of these supplements.
24.What are 'junk foods'?
This term has no specific meaning. It is an invented label which
some people have applied to foods of which they disapprove. It has,
for example, been applied indiscriminately to all fast food and all
snack foods. It has also been applied to any food high in fat and/or
sugar (and so in calories) but low in other nutrients. However, there
is no evidence that such foodsare other than acceptable as part of a
balanced diet.
ANSWERS TO GROUP 2 QESTIONS - FOOD SAFETY
***********************************
1.What is food poisoning?
Food poisoning is illness caused by any harmful amount of a
natural or contaminating substance in a food, but especially illness
caused by some highly infective kinds of bacteria. If not prevented
-- as it can be by care and good hygiene -- some kinds of bacteria
can grow to large numbers in food and produce toxins (poisons) some
of which are difficult to destroy by cooking. Other kinds can cause
illness by growing to large numbers in the digestive system. Symptoms
include abdominal pain, diarrhoea and vomiting, and may last from a
few hours to a few days. In extreme cases food poisoning can prove
fatal, especially to babies, the elderly and others with weakened
immune systems.
2.Why has food poisoning increased so much?
Food scientists and technologists in industry take great care to
try to ensure that food products are safe and wholesome. It is
probable that increased food poisoning statistics are due to a
combination of the following factors:-
1) increased public awareness, so that large numbers of
previously unreported 'stomach upsets' are now increasingly reported
as cases of food poisoning;
2) changing lifestyles, including changed shopping habits --
shopping less frequently in larger amounts and consequently storing
food for longer periods;
3) the increased marketing of chilled prepared dishes, which
need shorter times between purchase and consumption and more
carefully controlled low temperature domestic storage than many
people have understood or provided;
4) the emergence of some hitherto unknown or new strains of
micro-organisms.
3.Why all the fuss about food hygiene?
It is a fact of life that food is threatened by dangerous
microbes at every stage from farm to the table. So food safety calls
for many measures and great care at every stage or the food chain.
Leave a single loophole anywhere, and all the other efforts may be in
vain. So there are two overriding needs in the manufacture of safe
and wholesome foods; the first, in every food operation, knowledge of
what the law requires and of how to set up a sound method of handling
and an effective quality and safety control system; and the second,
knowledge and practice of food hygiene by everyone who handles or
takes decisions about handling, food, whether in factories,
distribution, retail, catering (foodservice) or in the home.
In addition to training of adults in food businesses, therefore,
many consumers need to learn a lot more about food hygiene, and
tomorrow's adults now at school should be taught food hygiene so that
it becomes second nature to them.
4.Aren't we losing natural immunity by producing foods with no pathogens
present?
That fear is groundless. The opposite view, that all food should
be completely sterile, is totally unrealistic. Bacteria are around us
all the time .There is no way that food can be made sterile, except
by putting it in an hermetically-sealed container (e.g. a can) and
treating it with a defined heat process to sterilise it; and even
then, once the can is opened, the food is exposed to the atmosphere
and contamination by airborne microorganisms. But when food is
consumed, it is not the presence of microorganisms that is of
concern. Danger only comes if they are allowed to multiply to large
numbers in food or in the digestive system. This is preventable by
taking great care and ensuring good hygiene at all stages of raw
material handling, manufacture, distribution, retailing, catering
(foodservice) and in the home.
5.How can food poisoning be prevented?
There is no single answer. It needs a combination of measures
and safeguards all the along the food chain from farm to table. See
the answer to FAQ 3 "Why all the fuss about food hygiene?"
6.What about irradiation of food?
Irradiation is a comparatively new method, one method among many,
of safe food preservation. It is, however, the only method (apart
from ultra-high pressure) of pasteurising without use of heat, and
can therefore be valuable in a limited number of cases; for example,
soft fruits and prawns, where quality is retained better than in heat
pasteurisation. It is a controversial technique but, despite media
scare stories, tests show that it is a safe and reliable process.
Whether, and to what extent, it will be used for any particular food
in a country will depend on governmental approval, economics and
public acceptance
As irradiated foods come on the market, so long as there is a
continuing public demand for unirradiated versions they will
obviously continue to be marketed alongside the irradiated versions.
But where the quality and safety of the irradiated products prove
superior, and the economics are viable, concerns will in time
disappear. This is exactly what happened a few generations ago when
similar concerns were expressed about permitting pasteurisation of
milk; yet today people happily and safely drink pasteurised milk. No
doubt the same will occur with acceptance of irradiated foods in the
future.
7.Isn't genetic modification a dangerous interference with nature?
Genetic modification has been used for countless years and
applies to all the food we eat. Traditional breeding methods to
improve animals and plants are genetic modification by slow,
hit-and-miss means. Science now enables it to be done systematically
and more rapidly. What is different, and could not be done by
traditional breeding, is the purposeful copying of genes from one
species to another.
Professional food scientists are concerned to serve the public
interest by furthering the application of science and technology to
all aspects of the supply of safe, wholesome, nutritious and
attractive food, nationally and internationally. The newer kinds of
genetic modification can provide immense benefits in human well-being
world-wide, especially in medicine, agriculture and food. Yes, like
every bit of mankind's progress from being a cave-dweller, it is a
form of interference with nature. Of course any new technology has
potential hazards. If these frightened mankind off all new
technologies we would still be living in the Stone Age. The answer is
for scientific effort to be made to foresee hazards and eliminate
them, for example, to avoid the risk of loss of genetic diversity.
That is why, for example, the introduction of any new
genetically-modified food is controlled in the UK in accordance with
the stringent assessment and recommendations of the UK Advisory
Committee on Novel Foods and Processes.
8.Doesn't gene transfer from one species to another create the risk of
ethical problems or even cannibalism?
The officially appointed UK Committee on the Ethics of Genetic
Modification and Food Use, chaired by the Rev. John Polkinghorne,
carried out a wide public consultation and issued a report in
September 1993 on all of the moral and ethical issues involved. This
was accepted by the UK Government and welcomed by IFST. The Committee
found that the concerns were misconceptions rather than of real
substance, arising from lack of knowledge, outside the scientific
community, of just what was involved.
The fact is that any gene extracted from one species for copying
into another, is not itself inserted but is copied in the laboratory
and diluted millions of times before a single gene is transferred.
The chance that the original gene would be found are much less than
the chance of recovering a particular drop of water from all the
oceans of the world. If this were widely understood fears of
cannibalism or of contravening religious food taboos would be seen to
be unwarranted. Unfortunately, this fact does not make good media
copy, whereas sensational "cannibalism" scare stories do.
The Polkinghorne Committee's conclusions were:
a. genetic modification of food and medicines is here to stay.
It is not something to be stopped, and it would not be ethically
right or necessary that it should be;
b. there is no reason for any ban on the use of copy genes of
human origin or from animals subject to dietary restrictions, but
scientists working in this field should be discouraged from using
such genes where alternatives would be equally effective;
c. products containing such copy genes should be labelled to
enabled consumers to make informed choices;
d. government and industry should look for ways of explaining
genetic modification to the general public.
9.Shouldn't all genetically modified foods, or those containing
genetically modified ingredients, be labelled as such, to warn
consumers?
There are two distinct kinds of genetic modification. The first
is as old as the hills, and applies to all the food we eat.
Traditional breeding methods of improvement are genetic modification
by slow, hit-and-miss means. Science now enables it to be done
systematically and more rapidly. That kind of modification
objectively needs no special label indication -- otherwise it would
have to be given on virtually all foods. Yet if the ready to eat
product still contains genes incorporated by modern methods, informed
consumer choice requires label information to that effect. In the UK
there is a voluntary agreement by manufacturers and retailers to give
such information, and a similar agreement is being developed across
the whole EU. These developments have been welcomed by IFST.
The second kind, which could not be done by traditional breeding,
is copying genes from one species to another. If some consumers wish,
for whatever reason, to avoid purchasing products of this second
kind, if the copy genes remain present in the food product, that
information should be given on the label.
This dual approach was adopted in the recommendations of the UK
Food Advisory Committee, accepted by the Government and welcomed by
IFST. It is now also the basis of EU law.
10.With regard to BSE, is British beef safe to eat?
BSE is an extremely serious disease of cattle, the eradication
of which is of primary importance to safeguard herds, and hence
future supply of dairy and bovine meat products for the human and pet
food chains, together with important bovine by-products. For there to
be any risk to humans consuming beef, two conditions would both have
to be fulfilled: that BSE could be transmitted from cows to humans;
and that parts of the animal capable of carrying the infective agent
could enter the human food chain.
As to the first, the emergence in the UK during 1994 to early
1996 of ten anomalous cases of Creutzfeldt-Jakob Disease (CJD) of a
previously unrecognised pattern, reviewed by the UK CJD Surveillance
Unit (CJDSU), led the Spongiform Encephalopathy Advisory Committee
(SEAC), in the absence of other explanation at the time, to the
conjecture that the UK cases were "most likely" to have been caused
by exposure to infected cattle brain or spinal cord before 1989 (at
which time they were banned from the food chain). Since then the
number of cases has slowly increased to over 20, and research has
resulted in some scientific evidence consistent with transmission, at
least to some humans.
As to the second, while the BSE infective agent can be detected
in the brain, spinal cord and retina of BSE-infected cows, extensive
tests have so far failed to detect it in muscle meat or milk of
infected cows. Measures have been taken, and strengthened, to exclude
from the food chain certain parts of the animal (specified bovine
materials, SBM), including all those parts shown to be capable of
carrying the infective agent. These measures require the most
stringent enforcement and heavy penalties for evasion. These
safeguards do not, of course, protect against possible consequences
of having consumed infective SBM in the past.
Having regard to the present scientific evidence, therefore, and
provided that the above measures are fully implemented, consumption
of muscle meat, milk and tallow from British cows, would appear to
involve virtually no risk of causing CJD, i.e. to be safe within the
normal meaning of the term. SEAC has stated that, if there is any
risk to humans, it is extremely small, and no greater for children,
hospital patients, pregnant women or people who are
immuno-compromised than for healthy adults.
As regards animal health, measures have been taken, and
strengthened, to reduce the incidence of BSE in cows and these have
led to a dramatic reduction in new cases and are expected to lead to
the virtual elimination of the disease.
On the basis of present scientific knowledge, no further
animal-related measures are needed.
While that sums up the present state of knowledge, scientists always
have to keep open minds. They have to act on existing knowledge while
recognising that further research will bring new information and
knowledge, which may in turn lead to revised conclusions.
ANSWERS TO GROUP 3 QUESTIONS - ADDITIVES AND PACKAGING
**********************
1.Why are food additives used?
Many foods depend on additives for safety, stability or
preservation. Preservatives inhibit growth of microbes that cause
food poisoning. Ham and bacon would be highly dangerous without the
preservative that also gives them their characteristic colour.
Freedom from separation, or a smooth creamy texture depends on
emulsifiers. Without other kinds of additives many foods would look
less pleasant, or taste less pleasant, or go off more quickly, or
cost more.
2.But aren't additives dangerous?
All additives in the UK and Europe are controlled by law, and
only those are permitted that have undergone stringent tests for need
and for safety in use, and have been been found satisfactory by
independent committees of scientists and medical experts. A similar
situation applies in most other countries. Some people are allergic
to, or intolerant of, particular additives; many more are allergic to,
or intolerant of, substances naturally present in foods, such as
strawberries, fish, nuts, etc.
3.Food colours are only cosmetic -- shouldn't they be banned?
Part of the enjoyment and appeal of food is its appearance,
including its colour. Homemakers, cooks and chefs have always used
colours in cooking to enhance appearance or to compensate for colour
deterioration during cooking. The same applies to some manufactured
foods. For example without colour margarines appear grey and
unpalatable; with colour they are visually attractive and popular.
The colours used are only those that have been tested and found
satisfactory by the same stringent procedures as those for additives
in general. Colour judiciously used adds to the enjoyment of food.
Would you want to return to only black-and-white on TV or on your
computer screen?
4.Why are foods packaged?
Foods are packaged to protect them and keep them in good
condition while they are delivered to stores, stacked on shelves or
stored at home.
5.What function does packaging perform?
The primary packaging of the food contains it; preserves it and
protects it from contamination or damage; carries the identification
and description of the contents; provides visible evidence as to
whether the package has been tampered with; and reduces household
waste by providing only the edible part of foods.
The outer packaging (e.g. paperboard cartons) is an essential
means of transporting to retail stores large quantities of the packs
for stacking on shop shelves.
6.Do we really need the protection that packaging is said to provide?
Yes. Food safety absolutely requires it. Moreover, a World
Health Organisation study has indicated that in developed countries
with sophisticated storage, packaging and distribution systems
wastage of food is estimated at only 2-3%. In developing countries
without these systems wastage is estimated at between 30% and 50%
7.Is packaging wasteful of materials and energy?
Of course the production of anything, including packaging
materials, uses raw materials and energy. However, both packaging
material manufacturers and food manufacturers operate in an intensely
competitive environment, causing continual search for ways to
minimise packaging costs without compromising the protection or
presentation of the product.
Packaging also reduces the amount of material entering the waste
stream. Most packaged fresh and processed foods have had the
non-edible material (e.g. husks, peels, vegetable tops, bones of
animal or fish, etc) removed during preparation. As a result, those
materials are used for animal feed or other purposes instead of going
into domestic waste. Likewise, energy is saved by not having to
transport that inedible material through the distribution and retail
chain to the consumer.
8.Can packaging and energy usage be reduced without compromising the
protection it gives to the food?
Here are four examples
In 1970, the weight of a metal can for baked beans was 68.9 g.
In 1990 the same size can weighed 56.6 g.
In 1950, a glass milk bottle weighed 397 g. In 1990, the same
size bottle weighed 245g.
In 1983 a 1.5 litre PET plastic soft drinks bottle weighed 66 g.
In 1990, the weight has been reduced to 42 g.
In 1950 a tinplate beer can weighed 91 g. In 1990 an aluminium
beer can weighed only 17 g, and was fully recoverable for recycling.
9.Why are there so many different types of packaging materials?
Most food products can be packed in a variety of alternative
ways. Manufacturers choose the most appropriate type of packaging for
a product, depending on the nature and requirements of the product,
the degree and nature of protection needed, the method of
distribution, the shelf-life and the environmental impact.
10.Why are some packages difficult to open?
the design of a package is inevitably a compromise between, on
the one hand, the essential protection of the contents, in some cases
requiring extra robustness or an airtight seal, and on the other hand,
easy and convenient use, including ease of opening. A really
well-designed pack is one that strikes an effective balance between
these two requirements. While there are some packs that are more
difficult to open than others, when an occasional pack is encountered
that is virtually impossible to open, it is usually the result of a
temporary maladjustment of a packaging machine (for example, forming
much too tight threading of a metal cap on a bottle) rather than a
design fault. Manufacturers are increasingly having their attention
drawn to the special 'openability' problems encountered by customers
with physical disabilities, and efforts to improve matters in this
direction will benefit all users
11.What about recycling of packaging?
The '3 R's' of current environmental packaging law and practice
are Reduce, Re-use and Re-cycle. These are the main ways of
minimising municipal waste disposal. As far as re-cycling of food
packaging is concerned is concerned, the major materials have to be
considered and dealt with separately.
Glass, tinplate and aluminium, when recovered by re-cycling, can
give similar performance to that provided by the virgin materials.
Re-cycling all three reduces overall energy usage (particularly with
aluminium). Re-cycling schemes are now in operation for the recovery
of both tinplate and aluminium containers. Glass containers (eg. milk
bottles) if sound can be returned and re-used; but broken glass
('cullet') is returned to the glassworks for re-cycling. Paper and
paperboard can be recovered and re-cycled for newsprint, tissues, and
some grades of paperboard.
Various plastic materials present a variety of recovery and
re-cycling problems. About half of all consumer goods are packaged in
plastic of one kind or another, yet, because of the lightweight
character of plastic packaging, it represents only 15% by weight. Its
light weight is of course economical of materials and energy for
transport of goods packed in plastic. Most individual plastic
packages (without counting the weight of contents) weigh less than 10
g, and some of these are contaminated with food residues such as
yogurt, fats, cream and similar products. The light weight makes it
more difficult to collect and transport for re-cycling. Lightweight
films, bags, pouches, etc made of plastics or plastics/paper
laminates are probably better incinerated to recover energy.
12.What about returnable, refillable systems?
There are several requirements for a re-fillable system to work.
Consumers must be made aware of which containers are returnable; the
operation is local, centred around each filling plant with a radius
of about 50-80 kilometers; the transport system for delivery and
returns is preferably controlled by the filling plant; the cost of
returning the empty container and of washing and handling it, must
not exceed the cost of a single-trip container; the containers must
be suitable for return by the consumer via conveniently sited bottle
banks.
13.Why does packaging contribute so much to household waste?
It is only when the package is emptied and needs to be disposed
of that we notice it. People are seldom aware of the role of the
packaging in protecting the product in distribution and until it is
opened for use.
A UK Royal Commission on Environmental Pollution found that
total packaging (not just food packaging) contributes 1% of the total
of all solid wastes. Total household waste contributes only 4% of all
solid wastes.
A study of waste by the US Chamber of Commerce indicated that
the relationship between food waste and packaging waste was clear; as
packaging use (and subsequent disposal as waste) increases, food
wastage decreases.
14.Do packaging materials affect the food in them?
The packaging material has both to preserve the food and to
protect it from deterioration, outside contamination or damage during
distribution and storage; and the packaging material in direct
contact with a food must not itself harm, or be harmed by, the food.
The packaging material for a particular food must therefore be
carefully selected with these considerations in mind. Most countries
have developed strict controls, based on extensive testing, for the
use of "food contact" materials; and these help to ensure that a
correct choice is made.
ANSWERS TO GROUP 4 QUESTIONS - SCIENCE AND FOOD
*****************************
1.What is food science? What is food technology?
*Note. The answers given are the same as the KEY DEFINITIONS
given at the beginning of this section, but are repeated here for
convenience
Food science --
is a coherent and systematic body of knowledge and understanding
of the nature and composition of food materials, and their behaviour
under the various conditions to which they may be subject.
Food technology --
is the application of food science to the practical treatment of
food materials so as to convert them into food products of the kind,
quality and stability, and so packaged and distributed, as to meet
the needs of consumers for safe, wholesome nutritious and attractive
foods.
Thus, food science integrates the application to food of several
contributory sciences. It involves knowledge of the chemical
composition of food materials (for all food consists entirely of
chemical substances); their physical, biological and biochemical
behaviour; human nutritional requirements and the nutritional factors
in food materials; the nature and behaviour of enzymes; the
microbiology of foods; the interaction of food components with each
other, with atmospheric oxygen, with additives and contaminants, and
with packaging materials; pharmacology and toxicology of food
materials, additives and contaminants; the effects of various
manufacturing operations, processes and storage conditions; and the
use of statistics for designing experimental work and evaluating the
results.
Likewise, food technology draws on, and integrates the
application to food of, other technologies such as those of steel,
tinplate, glass, aluminium, plastics, engineering, instrumentation,
electronics, agriculture and biotechnology.
2.Wouldn't our food be even better without scientists and technologists
interfering with it?
No. It is the scientists and technologists, working in
universities and research establishments, in industry, as consultants
to industry, and in enforcement and government agencies, who extend
the frontiers of knowledge about the properties and behaviour of food;
apply increasing knowledge to the development of the present (and
future) wide variety of safe and attractive foods; design and operate
quality assurance systems to ensure that quality and safety are
maintained during the manufacture, distribution and retailing of
foods; operate surveillance systems to ensure that legal, quality and
safety requirements are being met.
3.Why do scientific experts often disagree?
Personal opinions vary in every walk of life, but scientists
disagree far less than the media suggest. However, at the 'cutting
edge' of scientific research, there can be genuine disagreements on
the validity or interpretation of available information and on how
new research findings may affect previous interpretations. Scientists
are accustomed to debating these matters, and it is in the course of
thrashing out these differences and highlighting gaps of knowledge
where further research is needed, that scientific knowledge advances.
It requires objective judgement, without, on the one hand, undue
zealotry or, on the other hand, defence at all costs of entrenched
positions of past orthodoxy.
4.Doesn't hindsight show that the experts always "got it wrong"?
No. Hindsight shows that the experts nearly always "got it
right". It's simply that we only notice the rare instances where they
did get it wrong. And in those instances, we have to ask why.
Sometimes the scientists were in fact right, but human error occurred
in applying that knowledge. Sometimes it was that the knowledge
available at that time was insufficient. Scientists are not
magicians. Twenty years ago they knew only a fraction of what we know
now; which in turn is only a small fraction of what we will know in a
few years time. Research brings new knowledge all the time and at an
accelerating rate.
However, our profession is the repository of existing knowledge
in the field of food science and technology, and includes the
researchers expanding the boundaries of that knowledge and the
experts applying it for a safe, wholesome, nutritious and attractive
food supply for the public benefit.
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