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Irradiation and combination treatments
Irradiation and combination treatments David Kilcast discusses their effect on sensory properties Irradiation of food can cause chemical changes and these changes increase with increasing irradiation doses. The chemical changes can, in turn, give rise to changes in the colour, flavour and texture of certain foods. The successful use of irradiation will depend on achieving a useful required effect (e.g. on reducing microbial loading) whilst maintaining acceptably high sensory quality. The use of low irradiation doses in combination with other mild treatments will help achieve this aim.
The irradiation dose to be given to food is determined by the required useful effect; in order of increasing irradiation dose, this would in practice be inhibition of sprouting, elimination of insect infestation, destruction of spoilage microorganisms and destruction of pathogenic microorganisms. In principle, the greater the applied dose (up to the maximum permitted dose of 10 kGy) (HMSO, 1986) the greater the effect, but in practice the maximum tolerable dose is defined by undesirable changes in organoleptic characteristics. This paper will cover the chemical changes occurring during irradiation, the consequent organoleptic changes and the improvements that may be expected by using combination treatment as a means of reducing the required irradiation dose.
Chemical and organoleptic changes in foods Pigments
Changes in pigments on irradiation have been observed in a number of foods. Both white and red meats can undergo colour changes; chicken sometimes irradiated develops a pink coloration and irradiated red meats can develop a brown or grey coloration through formation of globin myohaemochromogen (Urbain, 1986). Seafoods can also undergo colour changes, for example slight colour loss in prawns (Snauwaert et al., 1973) and smoked salmon. Some loss of colour is also found in fruits such as strawberries, although at irradiation doses greater than Presented at the Conference ‘Irradiation and Combination Treatments, London, l-2 March 1990. Dr D. Kilcast is responsible for sensory analysis and food texture at Leatherhead Food Research Association, Randalls Road, Leatherhead. Surrey KT22 7RY, UK
6
Food Control - Januaty 199 1
would normally be used (Love11 and Flick, 1966). Irradiation of bananas at high doses can cause skin browning through increased polyphenoloxidase activity (Urbain, 1986). Coloured cheeses can also lose some pigmentation. Flavour
Changes in flavour on irradiation can arise from two main sourcesinitiation of rancidity development in lipids, and minor breakdown of proteins to give free sulphurcontaining compounds (Diehl, 1990). The combined effect of these two factors limits the maximum irradiation dose that can be applied to meats. Examples of quoted threshold doses are 1.5 kGy (turkey), 1.75 kGy (pork), 2.5 kGy (beef), 2.5 kGy (chicken), 3.5 kGy (rabbit) and 6.25 kGy (lamb) (Sudarmadji and Urbain, 1972). These doses are critically dependent on irradiation conditions, however, and increase with decreasing irradiation temperature. The undesirable flavour is often described as ‘wet dog’ or ‘metallic’, but the development of radiationinduced flavours is not necessarily unpleasant; for example, irradiation of chicken can enhance the characteristic chicken flavour (Ronay, 1989). Irradiation of fatty fish in the presence of oxygen can induce rancid flavours, which can be minimized by exclusion of oxygen. Irradiation of prawns enhances the characteristic flavour strength, which can often result in greater acceptability. Fruits and vegetables are generally deficient in the proteins and lipids that give rise to deteriorative flavour changes in other foods. Some flavour changes do occur, however. Strawberries can become less acidic and sweeter (Love11 and Flick, 1966), and can change in
characteristic strawberry flavour. Other fruits can also become for example grapes, sweeter, Flavour and cherries. melons changes in vegetables are less easily defined, but include flavour loss in production of bitter lettuce, flavours in parsnips and musty flavours in celery. It must be noted, however, that the effects on many fruits and vegetables depend on a number of factors such as cultivar type, maturity and growing conditions (Moy, 1983). Dairy products are generally more sensitive to off-flavour production than other foods, and acetaldehyde and dimethyl sulphide have been identified as radiolytic products. Off-flavours are produced in milk at doses <0.5 kGy through breakdown of protein and fat components (Gerrard, 1970). Cheese is slightly less sensitive to deterioration and improvements have been observed in the flavour of ripe camembert (Ronay, 1989). Generally, however, changes are undesirable, such as the formation of smoky flavours in cheddar cheese. Butter develops rancid notes at doses as low as 1 kGy. Other foods that are subject to flavour changes on irradiation are eggs (off-flavour development in the yolk) and baked goods (rancid/ metallic notes). Texture
Textural changes can occur in meat through breakdown of collagenous material (Bailey and Rhodes, 1964), producing an increase in tenderness. The most important textural changes, however, occur in fruits and vegetables through breakdown of carbohydrates. The eating quality of these foods is critically dependent on their text-Ural characteristics, which in turn are determined by carbohydrate cell wall components and, in some products, starch granules. Degradation of carbohydrates such as cellulose, pectin and starch produces softening, which is generally (but not always) undesirable. Such degradation can weaken rigid structural tissues or alter cell walls to reduce turgor. In addition, changes to tissues can release endogenous enzymes to locations where they can attack carbohydrates, or changes to carbohydrates can make them more susceptible to enzyme attack (Urbain, 1986).
0956-7135/91/010006-03
@ 1991 Butterworth-Heinemann
Ltd
Comment
The effect of irradiation depends not only on the type of product but also on cultivar type. Work on strawberries and raspberries has shown that, although some cultivars undergo unacceptable softening, others retain their firmness at doses up to 3 kGy (Foster and Kilcast, 1988). Grape skins lose their ‘bite’ (although tough skins can become tenderized), apples can become softer and powdery and other fruits such as cherries and mangoes become softer. Vegetables such as peppers and iceberg lettuce lose their characteristic crispness, although butterhead lettuces do not show significant changes. Cooking irradiated vegetables such as green beans produces a softening effect, which can be corrected by using shorter cooking times. At doses between 5 and 10 kGy, dried fruits show some softening, and irradiated dried vegetables can be rehydrated more rapidly (Farkas, 1988). In addition to flavour changes, irradiation of eggs produces two effects: weakening of the membrane separating the yolk and white resulting in leakage, and also loss in viscosity in the white. Implications to irradiation of ready meals
The majority of published work has concentrated on assessing the microbiological and organoleptic effects of irradiation on individual food items. There is consequently considerable information on the dose levels that can be used beneficially on individual items without incurring adverse organoleptic efects, but relatively little on mixed food systems in which individual items ideally require different optimum doses. Little is also known regarding possible interactive effects between different components. In a study carried out by the Leatherhead Food Research Association, the effect of electron beam irradiation on the microbiological and organoleptic quality of a range of hot and cold meats was studied. The aim of the study was to determine the doses at which a useful microbiological effect could be achieved without impairing the organoleptic quality (Kilcast, 1987). The meals were irradiated using a 10 MeV electron beam source at doses of 1,2, 3 and 4 kGy. Microbiological tests were carried out for total colony counts, total EnteroFood Control-
January 1991
bacteriaceae count, Staphylococcus count and yeast and mould count. Organoleptic assessments were carried out by a panel of 18 persons with previous experience of irradiated foods. The microbiological tests showed that irradiation reduced the numbers of organisms in all four groups studied, and that most of the lethal effect occurred after doses of 1 or 2 kGy. Enteric bacteria were reduced to very low or undetectable levels at these doses and S. aureus, when present, was reduced to undetectable levels. The organoleptic tests showed the anticipated trend in which the number of items rendered unacceptable by irradiation increased with increasing dose. At 1 and 2 kGy doses, 75 and 63% of individual food items, respectively, remained acceptable. Limiting factors were generally production of off-flavours and textural softening, and least change was noted in meals reheated and served hot and in items with stronger flavours. Of the 24% of items unacceptable at the lowest useful dose of 1 kGy, butter suffered from rancidity development, iceberg lettuce lost its characteristic crispness and green beans softened in texture. This latter effect could be avoided in practice by undercooking the vegetable slightly. This study demonstrated that valuable effects could be achieved at low doses, but that further dose reductions would be desirable to avoid complex menu selection procedures.
reduces the dose necessary to 0.75 kGy. Under this combined treatment, it may be expected that the irradiation component would have minimal effect on organoleptic properties, whereas the heat treatment might produce some deterioration. Similarly, the 0.7 kGy dose needed to disinfest dates can be reduced to 0.035 kGy by air heating at 40°C (Urbain, 1986). Combination of low-dose irradiation with chemical preservatives such as sodium chloride, sulphur dioxide or reduced pH has clear organoleptic implications, but changes other than flavour changes can also occur. Work at Leatherhead on combination of low-dose irradiation with low levels of sulphur dioxide in pork sausages has shown that colour loss can occur, reversible on exposure to air (Eves et al. , 1989). The effect of packaging also needs to be taken into account, especially when irradiation is being used in combination with modifiedatmosphere packaging. For example, irradiation of raspberries inpack at doses as low as 1 or 2 kGy can produce fermented off-flavours typical of anaerobic respiration. This could be minimized by use of packaging materials with more suitable permeability characteristics (Foster and Kilcast, 1988). Other better-known treatments that can be classified as combination treatments are controlled temperature during irradiation and controlled storage temperature.
Implications of combination treatments
Conclusions
In spite of the considerable research effort that has gone into the irradiation of food, relatively little is known regarding the implications of organoleptic changes in food to the consumer. In considering the effects of combination treatments, it is important to assess both the reduced level of change resulting from lower irradiation doses and the effect of any additional treatment. This will be particularly important for combination of irradiation with heat treatments and also for combination of irradiation with some chemical treatment. For example, irradiation of mould in papayas requires doses of 2.5-6 kGy, which causes substantial damage to the fruit. Use of a hot water dip at 60°C for 20 s, however,
In relation to other forms of food processing, both the primary chemical effect of irradiation and the secondary effect on organoleptic properties are very small. This factor is the main reason why it is proving so difficult to develop detection methods for irradiated food. Nonetheless, the small changes that do occur in certain sensitive foods carry the risk of consumer rejection if these are found to lower the perceived quality. It is therefore important to identify means by which the perceived food quality remains unaffected (or even improved) whilst the required effect, for example on microorganisms, is achieved. More research is required to identify
aureus
7
Comment
means by which irradiation doses can be minimized in sensitive foods and also to investigate the perception of irradiated food quality by consumers.
Bailey, A.J. and Rhodes, D.N. (1964) Treatment of meats with ionising radiations. XT. Changes in the texture of meat J. Sci
Food Agric. 15, 504 Diehl, J.F. (1990) Safety of Irradiated Foods Dekker,
New York
Eves, A., Kilcast, D., Blood, R.M. and Williams. A.P. (1989) Treatment of food with a combination of low-dose irradiation and conventional preservatives.
Leatherhead Food RA Research Report No. 647 (available to RA members only) Farkas, J. (1988) Irradiation of Dry Food Ingredients CRC Press Inc., Boca Raton Foster, T.E. and Kllcast, D. (1988) Effect of cultivar type on the sensory quality of selected irradiated fruits and vegetables.
Leatherhead Food RA Research Report No. 616 (available to RA members only) Gerrard, M. (1970) Milk preservation by ionising
Advisory Committee on Irradiated and Novel Foods, Her Majesty’s Stationery Office, London Kilcast, D. (1987) Electron beam treatment and its effect on flavours and textures. In:
Food
References
Marcel
Food Irrad. 11, 21 HMSO (1986) Report on the Safety and Wholesomeness of Irradiated Foods
radiation:
literature
review.
Safety towards the 2lst
Century
Wordsmith and Company, London, p. 115 Lovell, R.T. and Flick, G.J. (1966) Irradiation of Gulf Coast area strawberries.
Food Technol. 20 (7) 99 Moy, J.H. (1983) Radurization and Radicidation of Fruits and Vegetables in Preservation of Foods by Ionising Radiation Vol. 3 (Ed. E.S. Josephson and M.S. Peterson) CRC Press Inc., Boca Raton Ronav. E. (1989) Article in The Sundae/ Tkes, 16 July’1989
Snauwaert, (1973)
F., Tohhack,
P.P. and Maes, E.
Carotenoid stabilising during radurisation of the brown shrimp (Crangon vulgaris Fabr). Lebensm. Wiss. Tech-
nol. 6, 7 Sudarmadji, Flavour protein
S. and
Urbain,
W.J.
(1972)
sensitivity of selected animal foods to gamma radiation. J.
Food Sci. 37, 671 Urbain, W.J. (1986) Food Irradiation Academic Press, London
Regulating trade in irradiated food Metin Camcigil gives a personal view of the situation and how to minimize trade barriers All conventional food control measures should be equally applicable to irradiated food under the jurisdiction of general food regulations. Regulations special to irradiated food are only needed where required by the peculiarity of this food processing technique. At present there is no method to determine whether a foodstuff has been irradiated and this peculiarity necessitates governmental control at the point of the irradiation process. Special control measures which exist are the legal requirements of prior authorization for irradiation of individual or groups of foodstuffs for the operation of irradiation facilities, inspection of facilities and their operation, and certification that food has been irradiated in an authorized facility under the conditions inspected for compliance with the authorization. So that these special control measures do not constitute a barrier to free international trade, it is suggested that national regulations should be harmonized and that good irradiation practices and a certification system are standardized.
Governments have a function of protecting the public interest and trade in irradiated food may have to be regulated differently than regulation of the food trade in general. If the irradiation treatment of food is taken as fact, then we should consider how to appropriately and adequately control the processing and sale of irradiated food without hampering international trade. M. Camcigil is Special Assistant to the Director General, International Atomic Energy Agency, Wagramerstrasse 5, PO Box 100, A-1400, Vienna, Austria
8
Food Control - January 199 1
to ensure the above requirements do not constitute a barrier to trade. Thus it is important to design a control system which is effective but not prohibitive. Before discussing the nature and scope of an appropriate government control, it would be useful to briefly consider and distinguish from regulatory control two issues, namely fair trade practices (labelling and advertising) and industrial self control (quality control), in order to clearly delineate the boundaries of governmental control for the purposes of protecting public health and facilitating trade.
Regulating trade in food for the purpose of protecting public health was one of the earliest exercises of state authority. In more modern times, particularly in the currently dominant world of market economies, it is also the duty of authorities to lift barriers to trade and thus facilitate trade. Of these seemingly opposing responsibilities the former requires that correct and complete information on the product is given to the public (fair trade practices) and that the product does not constitute a hazard to public health. The latter requires that the controls
Control on labelling and advertising Controls to ensure that correct and complete information is given to the public regarding the nature and quality of a product involve the regulation of labelling and advertising. The term labelling is used here to mean an appropriate indication of the fact of irradiation on the legally required label. Although there is no scientific reason to indicate irradiation treatment on the label, it is necessary to do so in order to meet the right of the public to know. Hence, while labelling and advertising are generally regulated to protect the public from the possible harmful effects of wrong or information, in the concealed special case of labelling irradiated food the purpose is to give information which the public may want to know. It should be sufficient for the authorities to require a statement that the food has been irradiated in accordance with the regulations. There should be no need to regulate further the nature and scope of the statement, as it would be against the producer’s interest to give untrue adverse information. Any attempt by a government to give correct and complete information may be seen by the public as promotional, for it is difficult to distinguish information from promotion when marketing a product. The public is habitually suspicious of industry and does not fully trust the authorities. Public education activity should rest with the industry which is to benefit from it and it should not be a governmental function.
0956-7135/91 /010008-05
@ 1991 Buttemotth-Heinemann Ltd
The irradiation dose to be given to food is determined by the required useful effect; in order of increasing irradiation dose, this would in practice be inhibition of sprouting, elimination of insect infestation, destruction of spoilage microorganisms and destruction of pathogenic microorganisms. In principle, the greater the applied dose (up to the maximum permitted dose of 10 kGy) (HMSO, 1986) the greater the effect, but in practice the maximum tolerable dose is defined by undesirable changes in organoleptic characteristics. This paper will cover the chemical changes occurring during irradiation, the consequent organoleptic changes and the improvements that may be expected by using combination treatment as a means of reducing the required irradiation dose.
Chemical and organoleptic changes in foods Pigments
Changes in pigments on irradiation have been observed in a number of foods. Both white and red meats can undergo colour changes; chicken sometimes irradiated develops a pink coloration and irradiated red meats can develop a brown or grey coloration through formation of globin myohaemochromogen (Urbain, 1986). Seafoods can also undergo colour changes, for example slight colour loss in prawns (Snauwaert et al., 1973) and smoked salmon. Some loss of colour is also found in fruits such as strawberries, although at irradiation doses greater than Presented at the Conference ‘Irradiation and Combination Treatments, London, l-2 March 1990. Dr D. Kilcast is responsible for sensory analysis and food texture at Leatherhead Food Research Association, Randalls Road, Leatherhead. Surrey KT22 7RY, UK
6
Food Control - Januaty 199 1
would normally be used (Love11 and Flick, 1966). Irradiation of bananas at high doses can cause skin browning through increased polyphenoloxidase activity (Urbain, 1986). Coloured cheeses can also lose some pigmentation. Flavour
Changes in flavour on irradiation can arise from two main sourcesinitiation of rancidity development in lipids, and minor breakdown of proteins to give free sulphurcontaining compounds (Diehl, 1990). The combined effect of these two factors limits the maximum irradiation dose that can be applied to meats. Examples of quoted threshold doses are 1.5 kGy (turkey), 1.75 kGy (pork), 2.5 kGy (beef), 2.5 kGy (chicken), 3.5 kGy (rabbit) and 6.25 kGy (lamb) (Sudarmadji and Urbain, 1972). These doses are critically dependent on irradiation conditions, however, and increase with decreasing irradiation temperature. The undesirable flavour is often described as ‘wet dog’ or ‘metallic’, but the development of radiationinduced flavours is not necessarily unpleasant; for example, irradiation of chicken can enhance the characteristic chicken flavour (Ronay, 1989). Irradiation of fatty fish in the presence of oxygen can induce rancid flavours, which can be minimized by exclusion of oxygen. Irradiation of prawns enhances the characteristic flavour strength, which can often result in greater acceptability. Fruits and vegetables are generally deficient in the proteins and lipids that give rise to deteriorative flavour changes in other foods. Some flavour changes do occur, however. Strawberries can become less acidic and sweeter (Love11 and Flick, 1966), and can change in
characteristic strawberry flavour. Other fruits can also become for example grapes, sweeter, Flavour and cherries. melons changes in vegetables are less easily defined, but include flavour loss in production of bitter lettuce, flavours in parsnips and musty flavours in celery. It must be noted, however, that the effects on many fruits and vegetables depend on a number of factors such as cultivar type, maturity and growing conditions (Moy, 1983). Dairy products are generally more sensitive to off-flavour production than other foods, and acetaldehyde and dimethyl sulphide have been identified as radiolytic products. Off-flavours are produced in milk at doses <0.5 kGy through breakdown of protein and fat components (Gerrard, 1970). Cheese is slightly less sensitive to deterioration and improvements have been observed in the flavour of ripe camembert (Ronay, 1989). Generally, however, changes are undesirable, such as the formation of smoky flavours in cheddar cheese. Butter develops rancid notes at doses as low as 1 kGy. Other foods that are subject to flavour changes on irradiation are eggs (off-flavour development in the yolk) and baked goods (rancid/ metallic notes). Texture
Textural changes can occur in meat through breakdown of collagenous material (Bailey and Rhodes, 1964), producing an increase in tenderness. The most important textural changes, however, occur in fruits and vegetables through breakdown of carbohydrates. The eating quality of these foods is critically dependent on their text-Ural characteristics, which in turn are determined by carbohydrate cell wall components and, in some products, starch granules. Degradation of carbohydrates such as cellulose, pectin and starch produces softening, which is generally (but not always) undesirable. Such degradation can weaken rigid structural tissues or alter cell walls to reduce turgor. In addition, changes to tissues can release endogenous enzymes to locations where they can attack carbohydrates, or changes to carbohydrates can make them more susceptible to enzyme attack (Urbain, 1986).
0956-7135/91/010006-03
@ 1991 Butterworth-Heinemann
Ltd
Comment
The effect of irradiation depends not only on the type of product but also on cultivar type. Work on strawberries and raspberries has shown that, although some cultivars undergo unacceptable softening, others retain their firmness at doses up to 3 kGy (Foster and Kilcast, 1988). Grape skins lose their ‘bite’ (although tough skins can become tenderized), apples can become softer and powdery and other fruits such as cherries and mangoes become softer. Vegetables such as peppers and iceberg lettuce lose their characteristic crispness, although butterhead lettuces do not show significant changes. Cooking irradiated vegetables such as green beans produces a softening effect, which can be corrected by using shorter cooking times. At doses between 5 and 10 kGy, dried fruits show some softening, and irradiated dried vegetables can be rehydrated more rapidly (Farkas, 1988). In addition to flavour changes, irradiation of eggs produces two effects: weakening of the membrane separating the yolk and white resulting in leakage, and also loss in viscosity in the white. Implications to irradiation of ready meals
The majority of published work has concentrated on assessing the microbiological and organoleptic effects of irradiation on individual food items. There is consequently considerable information on the dose levels that can be used beneficially on individual items without incurring adverse organoleptic efects, but relatively little on mixed food systems in which individual items ideally require different optimum doses. Little is also known regarding possible interactive effects between different components. In a study carried out by the Leatherhead Food Research Association, the effect of electron beam irradiation on the microbiological and organoleptic quality of a range of hot and cold meats was studied. The aim of the study was to determine the doses at which a useful microbiological effect could be achieved without impairing the organoleptic quality (Kilcast, 1987). The meals were irradiated using a 10 MeV electron beam source at doses of 1,2, 3 and 4 kGy. Microbiological tests were carried out for total colony counts, total EnteroFood Control-
January 1991
bacteriaceae count, Staphylococcus count and yeast and mould count. Organoleptic assessments were carried out by a panel of 18 persons with previous experience of irradiated foods. The microbiological tests showed that irradiation reduced the numbers of organisms in all four groups studied, and that most of the lethal effect occurred after doses of 1 or 2 kGy. Enteric bacteria were reduced to very low or undetectable levels at these doses and S. aureus, when present, was reduced to undetectable levels. The organoleptic tests showed the anticipated trend in which the number of items rendered unacceptable by irradiation increased with increasing dose. At 1 and 2 kGy doses, 75 and 63% of individual food items, respectively, remained acceptable. Limiting factors were generally production of off-flavours and textural softening, and least change was noted in meals reheated and served hot and in items with stronger flavours. Of the 24% of items unacceptable at the lowest useful dose of 1 kGy, butter suffered from rancidity development, iceberg lettuce lost its characteristic crispness and green beans softened in texture. This latter effect could be avoided in practice by undercooking the vegetable slightly. This study demonstrated that valuable effects could be achieved at low doses, but that further dose reductions would be desirable to avoid complex menu selection procedures.
reduces the dose necessary to 0.75 kGy. Under this combined treatment, it may be expected that the irradiation component would have minimal effect on organoleptic properties, whereas the heat treatment might produce some deterioration. Similarly, the 0.7 kGy dose needed to disinfest dates can be reduced to 0.035 kGy by air heating at 40°C (Urbain, 1986). Combination of low-dose irradiation with chemical preservatives such as sodium chloride, sulphur dioxide or reduced pH has clear organoleptic implications, but changes other than flavour changes can also occur. Work at Leatherhead on combination of low-dose irradiation with low levels of sulphur dioxide in pork sausages has shown that colour loss can occur, reversible on exposure to air (Eves et al. , 1989). The effect of packaging also needs to be taken into account, especially when irradiation is being used in combination with modifiedatmosphere packaging. For example, irradiation of raspberries inpack at doses as low as 1 or 2 kGy can produce fermented off-flavours typical of anaerobic respiration. This could be minimized by use of packaging materials with more suitable permeability characteristics (Foster and Kilcast, 1988). Other better-known treatments that can be classified as combination treatments are controlled temperature during irradiation and controlled storage temperature.
Implications of combination treatments
Conclusions
In spite of the considerable research effort that has gone into the irradiation of food, relatively little is known regarding the implications of organoleptic changes in food to the consumer. In considering the effects of combination treatments, it is important to assess both the reduced level of change resulting from lower irradiation doses and the effect of any additional treatment. This will be particularly important for combination of irradiation with heat treatments and also for combination of irradiation with some chemical treatment. For example, irradiation of mould in papayas requires doses of 2.5-6 kGy, which causes substantial damage to the fruit. Use of a hot water dip at 60°C for 20 s, however,
In relation to other forms of food processing, both the primary chemical effect of irradiation and the secondary effect on organoleptic properties are very small. This factor is the main reason why it is proving so difficult to develop detection methods for irradiated food. Nonetheless, the small changes that do occur in certain sensitive foods carry the risk of consumer rejection if these are found to lower the perceived quality. It is therefore important to identify means by which the perceived food quality remains unaffected (or even improved) whilst the required effect, for example on microorganisms, is achieved. More research is required to identify
aureus
7
Comment
means by which irradiation doses can be minimized in sensitive foods and also to investigate the perception of irradiated food quality by consumers.
Bailey, A.J. and Rhodes, D.N. (1964) Treatment of meats with ionising radiations. XT. Changes in the texture of meat J. Sci
Food Agric. 15, 504 Diehl, J.F. (1990) Safety of Irradiated Foods Dekker,
New York
Eves, A., Kilcast, D., Blood, R.M. and Williams. A.P. (1989) Treatment of food with a combination of low-dose irradiation and conventional preservatives.
Leatherhead Food RA Research Report No. 647 (available to RA members only) Farkas, J. (1988) Irradiation of Dry Food Ingredients CRC Press Inc., Boca Raton Foster, T.E. and Kllcast, D. (1988) Effect of cultivar type on the sensory quality of selected irradiated fruits and vegetables.
Leatherhead Food RA Research Report No. 616 (available to RA members only) Gerrard, M. (1970) Milk preservation by ionising
Advisory Committee on Irradiated and Novel Foods, Her Majesty’s Stationery Office, London Kilcast, D. (1987) Electron beam treatment and its effect on flavours and textures. In:
Food
References
Marcel
Food Irrad. 11, 21 HMSO (1986) Report on the Safety and Wholesomeness of Irradiated Foods
radiation:
literature
review.
Safety towards the 2lst
Century
Wordsmith and Company, London, p. 115 Lovell, R.T. and Flick, G.J. (1966) Irradiation of Gulf Coast area strawberries.
Food Technol. 20 (7) 99 Moy, J.H. (1983) Radurization and Radicidation of Fruits and Vegetables in Preservation of Foods by Ionising Radiation Vol. 3 (Ed. E.S. Josephson and M.S. Peterson) CRC Press Inc., Boca Raton Ronav. E. (1989) Article in The Sundae/ Tkes, 16 July’1989
Snauwaert, (1973)
F., Tohhack,
P.P. and Maes, E.
Carotenoid stabilising during radurisation of the brown shrimp (Crangon vulgaris Fabr). Lebensm. Wiss. Tech-
nol. 6, 7 Sudarmadji, Flavour protein
S. and
Urbain,
W.J.
(1972)
sensitivity of selected animal foods to gamma radiation. J.
Food Sci. 37, 671 Urbain, W.J. (1986) Food Irradiation Academic Press, London
Regulating trade in irradiated food Metin Camcigil gives a personal view of the situation and how to minimize trade barriers All conventional food control measures should be equally applicable to irradiated food under the jurisdiction of general food regulations. Regulations special to irradiated food are only needed where required by the peculiarity of this food processing technique. At present there is no method to determine whether a foodstuff has been irradiated and this peculiarity necessitates governmental control at the point of the irradiation process. Special control measures which exist are the legal requirements of prior authorization for irradiation of individual or groups of foodstuffs for the operation of irradiation facilities, inspection of facilities and their operation, and certification that food has been irradiated in an authorized facility under the conditions inspected for compliance with the authorization. So that these special control measures do not constitute a barrier to free international trade, it is suggested that national regulations should be harmonized and that good irradiation practices and a certification system are standardized.
Governments have a function of protecting the public interest and trade in irradiated food may have to be regulated differently than regulation of the food trade in general. If the irradiation treatment of food is taken as fact, then we should consider how to appropriately and adequately control the processing and sale of irradiated food without hampering international trade. M. Camcigil is Special Assistant to the Director General, International Atomic Energy Agency, Wagramerstrasse 5, PO Box 100, A-1400, Vienna, Austria
8
Food Control - January 199 1
to ensure the above requirements do not constitute a barrier to trade. Thus it is important to design a control system which is effective but not prohibitive. Before discussing the nature and scope of an appropriate government control, it would be useful to briefly consider and distinguish from regulatory control two issues, namely fair trade practices (labelling and advertising) and industrial self control (quality control), in order to clearly delineate the boundaries of governmental control for the purposes of protecting public health and facilitating trade.
Regulating trade in food for the purpose of protecting public health was one of the earliest exercises of state authority. In more modern times, particularly in the currently dominant world of market economies, it is also the duty of authorities to lift barriers to trade and thus facilitate trade. Of these seemingly opposing responsibilities the former requires that correct and complete information on the product is given to the public (fair trade practices) and that the product does not constitute a hazard to public health. The latter requires that the controls
Control on labelling and advertising Controls to ensure that correct and complete information is given to the public regarding the nature and quality of a product involve the regulation of labelling and advertising. The term labelling is used here to mean an appropriate indication of the fact of irradiation on the legally required label. Although there is no scientific reason to indicate irradiation treatment on the label, it is necessary to do so in order to meet the right of the public to know. Hence, while labelling and advertising are generally regulated to protect the public from the possible harmful effects of wrong or information, in the concealed special case of labelling irradiated food the purpose is to give information which the public may want to know. It should be sufficient for the authorities to require a statement that the food has been irradiated in accordance with the regulations. There should be no need to regulate further the nature and scope of the statement, as it would be against the producer’s interest to give untrue adverse information. Any attempt by a government to give correct and complete information may be seen by the public as promotional, for it is difficult to distinguish information from promotion when marketing a product. The public is habitually suspicious of industry and does not fully trust the authorities. Public education activity should rest with the industry which is to benefit from it and it should not be a governmental function.
0956-7135/91 /010008-05
@ 1991 Buttemotth-Heinemann Ltd