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Historical changes in the mineral content of fruits and vegetables: a continuing controversy
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Tracing nutrients from soil to humans: the example of zinc, rice and the nutritional status of children in Bangladesh
A.B. Mayer et al., Division of Nutritional Sciences, Cornell University, USA
The idea that nutritional deficiency in humans can have its origin in the soil is not new, but has received little recent research attention. In Bangladesh, soil zinc deficiency is widespread and the population is at risk of zinc deficiency due largely to poor dietary intake. Using the example of zinc, studies were designed to trace this nutrient from soil to paddy rice, to processed rice, to the whole diet and finally to the nutritional status of children. The various challenges on this journey will be presented. Samples of raw, parboiled, milled and cooked rice and soil were collected in Bangladesh. Raw rice zinc content was related to soil zinc, pH and texture; land elevation and rice variety by multiple regression analysis. Milling reduced the zinc content by 31%, with almost two-fold differences between villages. On average 9% was lost from cooking; more when cooking water was discarded. Forty households from each village were enrolled in a diet, nutrition and socio-economic survey. Zinc intake from rice was individualized using household samples of milled rice. Hair samples from children were used for zinc and heights and weights for overall nutritional status. One village had "high zinc" polished rice (1.78 mg/100g), two had "low zinc" rice (1.10 and 1.12 mg/100g) and one was average (1.35 mg/100g). Rice supplied 64% of children's dietary zinc. On average, dietary zinc from all sources would increase from 6.4 mg/d on a "low zinc" rice diet to 9.0 on a "high zinc" rice diet. Hair zinc was positively related to the polished rice zinc content (r = 0.24 p = 0.001). Optimizing the micronutrient content of rice through changes in agriculture and processing, along with other interventions that address the many causes of malnutrition would be very helpful in Bangladesh and other countries where such reliance is placed on one staple crop.
References
Brown, K. H., Wuehler, S. E. and Peerson, J. M. (2001) Food and Nutrition Bulletin, 22, 113-125
Mayer, A. B., Latham, M. C., Duxbury, J. M., Hassan, N. and Frongillo, E. A. (2003) Proceedings of the Nutrition Society, 62, 35A-93A
Moslehuddin, A. Z., Laizoo, S. and Egashira, K. (1999) Communications in soil science and plant analysis, 30, 1975-1996
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TECHNICAL SEMINAR 11: Soil Management and Crop Quality, Talk 3
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Effects of Soil and Foliar Application of Chloride and Zinc on Uptake and Accumulation of Cadmium in Wheat and Vegetables
Ismail Cakmak, Sabanci University, Turkey
Accumulation of cadmium (Cd) in food crops is a growing concern in both high input and low input crop production systems. Long-term consumption of food crops with increasing concentration of Cd is an inreasing threat to human health. There are several factors affecting the uptake and accumulation of Cd in plants. Among these factors, soil salinity and soil zinc (Zn) status play a critical role (Cakmak et al., 2000; Oliver et al., 1997; Weggler et al., 2004). In the present study, several pot experiments have been conducted to follow the effects of different forms and doses of salts in soils and Zn nutritional status of plants on Cd accumulation of wheat, lettuce and spinach. Increasing supply of NaCl, KCl and CaCl2 in soil markedly enhanced Cd concentration in leaves and total amount of Cd per plant while KCl and Ca (NO3) 2 remained less effective. Accumulation of Cd in plants became more pronounced when supplied in form of CdCl2 when compared to Cd(NO3)2 and Cd(SO4)2. Also in the case of foliar application of NaCl or CdCl2, or dipping flag leaves in a NaCl solution stimulated Cd transport from leaves into grain. These effects of Cl on uptake and transport of Cd seem to be very specific to Cd because Zn concentration of plants was not affected by such different Cl treatments. To reduce NO3 accumulation in vegetables by partial replacement of NO3 by Cl is being considered as an approach by different research groups; however, this approach caused enhanced an accumulation of Cd in spinach and lettuce. Improving Zn nutritional status of plants very significantly reduced both Cd uptake by roots and Cd transport from shoot into grain. Foliar application of Zn resulted in a strong decreasing effect on Cd retranslocation from leaves into grain. The results indicate that increased concentration of Zn in soil or shoot tissue play a decisive role in reducing Cd uptake by roots or inhibiting Cd transport into grain. Possibly, there is common mechanism(s) or transporters for uptake and translocation of Cd and Zn during root uptake and phloem loading which lead to a competition between 2 metals for uptake into root cells and loading into phloem cells. The mechanism of Cl-induced Cd accumulation in shoot or grain could not be well understood. As discussed previously (Norvell et al., 2000; Weggler et al., 2004), possibly, a certain “Cd-Cl formation” is possibly involved in Cd uptake and translocation, or Cl improves solubility/mobility of Cd bound to soil constituents and apoplast of root/leaf tissues by a “chloro-complexition” of Cd.
References
Cakmak I, Welch RM, Erenoglu B, Romheld V, Norvell WA, Kochian LV. 2000: Influence of varied zinc supply on re-translocation of cadmium (Cd-109) and rubidium (Rb-86) applied on mature leaf of durum wheat seedlings. Plant and Soil, 219: 279-284
Norvell WA, Wu J, Hopkins DG, Welch RM. 2000: Association of cadmium in durum wheat grain with soil chloride and chelate-extractable soil cadmium. Soil Sci. Soc. Am. J. 64: 2162-2168
Oliver DP, Wilhelm NS, McFarlane JD, Tiller KG, Cozens GD. 1997: Effect of soil and foliar applications of zinc on cadmium concentration in wheat grain. Aust. J. Exp. Agric. 37:677-681
Weggler K, McLaughlin MJ, Graham RD. 2004: Effect of chloride in soil solution on the plant availability of biosolid-borne cadmium. J. Environ. Qual. 33: 496-504
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TECHNICAL SEMINAR 11: Soil Management and Crop Quality, Talk 4
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Comparison of the quality of organic and conventional crops
Jana Hajšlová et al., Institute of Chemical Technology, Czech Republic
Growing consumers' interest in organically produced foods obviously reflects escalating public concern about environmental and personal health issues. In order to be able to make a free and informed choice between organic and conventional foods, an objective assessment of a product quality based on a sound scientific knowledge is needed.
In our project, an attempt was made to determine the quality of vegetables from organic farming systems as compared to that of crops from conventional farming employing a number of various parameters. Different potato (Solanum tuberosum) varieties were used in controlled field trials conducted in two separate localities in Czech Republic. To determine possible inter-annual variations experiments were performed on four consecutive crops. The parameters studied included both the nutritional quality, occurrence of potentially toxic agents, sensory properties and factors related to the rate of fresh tuber enzymatic browning. Selected agronomic parameters were also compared.
The second study was focused on the occurrence furanocoumarins in celery, parsnip and carrot (Umbelliferae) purchased at Czech and Swedish market. The influence of various stress factors such as mechanical damage, attack of insects or fungi and unfavourable climatic /storage conditions on the levels of these natural toxicants in crops from alternative production systems was evaluated.
The third study was concerned with comparison of organic and conventional basils (Ocimum basilicum L.). Altogether five pairs were examined. Some differences in flavour profiles obtained by solid phase micro-extraction technique of head-space volatiles and subsequent gas chromatographic separation employing mass spectrometric detection were recognized.
References
J. Hajšlová, V. Schulzová, P. Slanina, K. Janné, K. E. Hellenäs, Ch. Andersson, Food Addit. Contam. (in press)
M. Friedman, J. Chromatogr. A 1054, 143 (2004)
V. Schulzová, R. Peroutka, J. Hajšlová, Polish J. Food Nutr. Sci., 11/52, 25 (2002)
TemaNord: Furanocoumarins in Plant Food, 1996
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TECHNICAL SEMINAR 11: Soil Management and Crop Quality, Related Poster 1
Related to QLIF WP 2.1 (2.1.6)
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Livestock products
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Healthier organic livestock products; Antioxidants in organical and conventional produced milk
Jacob Holm Nielsen & Tina Lund-Nielsen
The Danish Institute of Agricultural Sciences (DIAS) has over the period May 2003 to February 2004 carried out studies of the content of potential antioxidants and vitamins in organic and conventional milk. Once a month, a milk sample was taken from the silo tanks at Arla Foods Hobro dairy plant, where large amounts of organic and conventional milk are processed. The studies comprised a number of fat-soluble vitamins and the composition of fatty acids in the milk.
One of the components that were given most attention was the content of vitamin E (a-tocopherol), The analyses showed that organic milk in 7 out of 10 samples contained significantly more a-tocopherol. The results indicate that in general addition of synthetic a-tocopherol is lower in the organic milk production, and in spite of this, the content of a-tocopherol is higher in organic milk than in conventionally produced milk.
The content of carotenoids is also higher in organic milk, and the content of b-caroten is 2- to 3-fold higher in organic milk than in conventional milk.
The higher concentrations of a-tocopherols and carotenoids in organic milk are a result of feeding differences between the conventional and the organic productions. The most important reason for the found differences is presumably the large amounts of maize silage used in the conventional production, whereas a not inconsiderable amount of grass and leguminous plants is used in the organic production. If the organic farmers wish to produce milk with a high level of these components in the future, the share of maize in the feed rations should not be increased.
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PLENARY SESSION: Healthier Organic Livestock Products; Improving nutritional quality and avoiding microbial infection, Lecture 1
Related to QLIF WP 2.2 (2.2.1)
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Healthier Organic Livestock Products; avoiding microbial infection
David R. Davies, Institute of Grassland and Environmental Research, UK
If we take the case of the Escherichia coli 0157:H7, since the first identification of this strain as a human pathogen in 1982, there has been considerable research effort on the organism and to date there are many hundred research papers on the subject. In the UK the organism is predominantly associated with food borne disease resulting from beef and milk products. However, it is increasingly associated with disease as a result of visits to the countryside which is not surprising considering fewer than 700 cells (Tuttle et al. 1999) and maybe as few as 10 are required to cause human illness. Research has focused on it’s prevalence in herds, (effects of season, stress, starvation etc) survival in various media (faeces, milk etc) and control methods from the point of slaughter in the abattoir to post-slaughter processing. Like so many food borne bacterial pathogens E. coli O157:H7 is associated with infections in young, old, pregnant, and immuno-compromised individuals which gives a risk group of 20% of the population, so there is a potentially large vulnerable population. However, the animal on farm must be the primary point for combating this problem. In a recent UK survey of cattle, sheep, pigs and poultry at slaughter (Chapman et al. 1997) E. coli O157 was isolated from 15.7% of cattle, 2.2% of sheep, 0.4% of pigs and was not found in chickens. In a separate study (Mechie et al., 1997) 74% of animals that excreted E. coli O157 did so only on one occasion, highlighting the importance of repetitive sampling of animals.
The effect of diet on faecal shedding has been examined in a number of studies. Harmon et al. (1999) indicated that calves fed a diet high in Bermuda hay had on average 10-fold fewer E. coli 0157 than those fed a predominantly grain diet. Dargatz et al. (1997) also indicated feeding high grain diets was associated with faecal shedding of E. coli 0157. Within forage diets there is evidence of differences in E. coli shedding. For example diets containing red clover have been shown to reduce pathogen load in cattle (Garber et al 1995). However, the feeding of maize silage has been associated with significantly higher levels of faecal output of E. coli 0157 than feeding of other forages (Herriot et al. 1998). These findings will be considered in the context of feeding dairy cows on intensive high grain versus low input high forage based rationing systems.
References
Dargatz, D.A., Wells, S.J., Thomas, L.A., Hancock, D.D. and Garber, L.P. (1997). Factors associated with the presence of Escherichia coli 0157 in faeces of feedlot cattle. Journal of Food Protection 5: 466 – 470.
Garber, L.P., Wells, S.J., Hancock, D.D., Doyle, M.P.,Tuttle, J., Shere, J.A. and Zhao, T. (1995). Risk factors for faecal shedding of Escherichia coli 0157:H7 in dairy calves. Journal of the American Veterinary Medicine Association 207: 46 – 49.
Harmon, B.G., Doyle, M.P., Brown, C.A., Zhao, T., Tkalic, S., Mueller, E., Parks, A.H., and Jacobsen, K. (1999). Faecal shedding and rumen proliferation of Escherichia coli 0157:H7 in dairy calves: An experimental approach. In Escherichia coli 0157 in farm animals ed. Stewart C.S. and Flint H.J. pp 59 – 70 Wallingford, UK CAB International.
Herriot, D.E., Hancock, D.D., Ebel, E.D., Carpenter, L.V., Rice, D.H. and Besser, T.E. (1998). Association of herd management factors with colonization of dairy cattle by shiga toxin-positive Escherichia coli 0157. Journal of Food Protection 61: 802 – 808.
Mechie, S.C., Chapman, P.A. and Siddons, C.A. (1997). A fifteen month study of Escherichia coli 0157:H7 in a dairy herd. Epidemiology and infection 118: 17 – 25.
Tuttle, J., Gomez, M., Doyle, M.P., Wells, J.G., Zhao, T., Tauxe, R.V. and Griffin, P.M. (1999). Lessons from a large outbreak of Escherichia coli 0157:H7 infections: insights into the infectious dose and method of widespread contamination of hamburger patties. Epidemiology and Infection 122: 185 – 192.
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PLENARY SESSION: Healthier Organic Livestock Products; Improving nutritional quality and avoiding microbial infection, Lecture 2
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Implementation of the EU standards related to animal health and food safety. An analysis involving 24 countries in the European Network SAFO
Albert Sundrum et al., Kassel University, Germany
In the EU substantial diversity exists in organic livestock farming between the countries, in relation to species farmed, development and importance of the organic livestock sector and practices as well as with respect to geographical, traditional, cultural and climatic conditions for farming. Yet, all member countries have implemented the same EU-regulation on organic farming. One objective of the work in the EU concerted action Network ‘Sustaining Animal Health and Food Safety in Organic Farming’ (SAFO) is to identify constraints and difficulties connected with the implementation of the EU standards in the partner countries. A questionnaire was circulated and returned by partners representing 24 countries, the responses were based on consultation with national certification bodies, organisations and researchers with experience in organic livestock farming. The analysis focused on 1) national differences between countries with regard to the daily practice and possibilities of organic livestock farming and 2) problems associated to the implementation of the standards. Many differences on national level compared to the EU standards were discovered, although most of them were related to the degree of details and additional guide lines. The majority of problems were connected with the implementation of the ideas of organic animal husbandry in the different regions of Europe, rather than to the formulation of the standards themselves. Conflicts were identified between the EU-regulation for organic agriculture and other EU-directives in the area of disease treatment (homoeopathy). The diversity between member states, highlighted in detail in some of the responses, can partly explain some of the differences found in what are considered problem areas of organic livestock production and with regard to food quality and safety in the various participating countries.
References
Vaarst, M. 2004. The SAFO-Network on its way forward. Proc. 2nd SAFO-Workshop, Witzenhausen, Germany, p. 269-272.
Vaarst, M., Roderick, S., Lund, V., and Lockeretz, W. (eds.) 2004. Animal Health and Welfare in Organic Agriculture. CABI Publishing, Wallingford, UK.
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TECHNICAL SEMINAR 12: Livestock husbandry and meat quality, Talk 1
Related to QLIF WP 4.4 (4.4.1)
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Integrating organic livestock production in new EU membership countries with focus on animal health and food quality
R. Leming et al., Estonian Agricultural University, Estonia
In the European Union, we all face the challenge of implementing the same framework of legislation in widely diverse countries. The implementation of ideas and standards of organic farming is no exception with regard to major challenges. In the EU concerted action network ‘Sustaining Animal Health and Food Safety in Organic Farming’, one of the aims is to support this process, including exchange of knowledge and experience. In many of the new EU member states, the organic crop production sector (including vegetables and fruit) is much better developed than the livestock sector. The diversity between regions of the new member states is as big as in the rest of EU, but small scale farming and small herds are characteristic for large parts of these countries. The potential for converting to organic farming is good, since many farms do not import chemical inputs and are to a large extent self-sufficient, e.g. in feedstuffs. Other problems may exist in some regions, e.g. the use of common grazing areas, meaning that a whole village in principle should convert to organic farming, if the livestock and land areas used for grazing are to be certified. The new membership countries face to different degrees a number of major challenges, such as home markets which are not yet well developed for organic livestock products, and lack of experience with the organic farming system among agricultural and veterinary professionals. In the presentation, an overview of organic livestock production and animal food production in 8 new and emerging member states will be presented. The challenges with regard to implementation of the EU-standards and animal food production from farm level to market will be presented and discussed.
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TECHNICAL SEMINAR 12: Livestock husbandry and meat quality, Talk 2
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Ecoli 0157 in the farm environment - their influence on the foodchain
I.D. Ogden & N.J.C. Strachan, School of Medicine & University of Aberdeen, UK.
Verocytotoxigenic E. coli (VTEC) are a severe human pathogen with symptoms ranging from mild diarrhoea to death (Griffin & Tauxe 1991) and a reservoir deep within the farm ruminant population (Paiba et al., 2002). The serotype most commonly identified worldwide is O157 (Willshaw et al., 2001) which has been responsible for a number of large outbreaks in the UK, USA and Japan. In south Europe and Australia, other serotypes e.g. O26 and O111 are also routinely isolated (World Health Organisation 1998). This paper presents VTEC prevalence levels in cattle and sheep and describes the numbers shed in faeces that contribute both to the load in the farming environment and contamination levels in food products. A small but significant number of animals shed high numbers (104-6 /g) of E. coli O157 (Ogden et al., 2004; Ogden et al. in press) which constitute >96% of the pathogen in a group of animals. Routes of human infection are compared with each other using outbreak data, case-control studies and quantitative microbial risk assessment. Potential methods of control within the host at farm level are discussed and evaluated against current controls within the food industry.
References
Griffin, P.M. and Tauxe, R.V. (1991) The epidemiology of infections caused by E. coli O157:H7, other enterohemorrhagic E. coli and the associated hemolytic uremic syndrome. Epidemiol. Rev. 13, 60-98.
Ogden ID, MacRae, M & Strachan NJC 2004 Is the prevalence and shedding concentrations of E. coli O157 in beef cattle in Scotland seasonal? FEMS Microbiology Letters 233, 297–300.
Ogden,I. D. MacRae,M. Strachan,N. J. C. Concentration and prevalence of Escherichia coli O157 in sheep faeces at pasture in Scotland J.Appl.Microbiol. In press.
Paiba, G.A., Gibbens, J.C., Pascoe, S.J.S., Wilesmith, J.W., Kidd, S.A., Byrne, C., Ryan, J.B.M., Smith, R.P., Mclaren, I.M., Futter, R.J., Kay, A.C.S., Jones, Y.E., Chappell, S.A., Willshaw, G.A. and Cheasty, T. (2002) Faecal carriage of verocytotoxin-producing Escherichia coli O157 (VTEC O157) in cattle and sheep at slaughter in Great Britain. Vet. Rec. 150, 593-598.
Willshaw, G.A., Cheasty, T., Smith, H.R., O’Brien, S.J. and Adak, G.K. (2001) Verocytotoxin-producing Escherichia coli (VTEC) O157 and other VTEC from human infections in England and Wales 1995-1998. J.Med. Microbiol. 50, 135-142.
World Health Organisation (1998) Zoonotic non-O157 Shiga toxin producing Escherichia coli (STEC). Report of a WHO scientific working group meeting June 1998, WHO/CSR/APH/98.8. http://www.who.int/emc-documents/zoonoses/docs/whocsraph988.pdf
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TECHNICAL SEMINAR 13: Dairy nutrition and milk quality, Talk 2