J Sci Food Agric 87:2757–2762 (2007)
Review Quality of plant products from organic agriculture
Organic Foodstuffs Division, Faculty of Human Nutrition and Consumer Sciences, Warsaw Agricultural University, Nowoursynowska 159 C, PL-02 776 Warszawa, Poland
Abstract: During the last decade, consumers’ trust in food quality has decreased drastically, mainly because of growing ecological awareness and several food scandals (e.g. BSE, dioxins, bacterial contamination). It has been found that intensive conventional agriculture can introduce contaminants into the food chain. Consumers have started to look for safer and better controlled foods produced in more environmentally friendly, authentic and local systems. Organically produced foods are widely believed to satisfy the above demands, leading to lower environmental impacts and higher nutritive values. So far, studies have partly conﬁrmed this opinion. Organic crops contain fewer nitrates, nitrites and pesticide residues but, as a rule, more dry matter, vitamin C, phenolic compounds, essential amino acids and total sugars than conventional crops. Organic crops also contain statistically more mineral compounds and usually have better sensory and long-term storage qualities. However, there are also some negatives: plants cultivated in organic systems generally have 20% lower yields than conventionally produced crops. Several important problems need to be addressed in the coming years: environmental, bacterial and fungal contamination of organic crops and, the most essential issue, the impact of organic food consumption on animal and human health. © 2007 Society of Chemical Industry
Keywords: organic plant crops; quality; yield; composition; nutrition; vitamins; phenolics; sugars; nitrates; nitrites; pesticides; dry matter; health; sensory qualities
FACTORS INFLUENCING THE QUALITY OF ORGANIC PLANT FOOD PRODUCTS There are several important factors inﬂuencing the quality of food products that also are relevant to organically produced plant products. As illustrated in Fig. 1, the basic factors are the quality of the environment (abiotic factors) and the levels of pest and pathogen damage (biotic factors) to which plants are subjected. The main components of the environment (air, water, soil) have to be unpolluted if the crops obtained are expected to be of high nutritive quality. Many environmental contaminants enter the food production chain (soil–plant–animal–human organism), causing signiﬁcant problems in human health.1 These contaminants include heavy metals, pesticide residues, nitrogen compounds, mycotoxins, chlorinated biphenyls (PCBs), aromatic hydrocarbons (e.g. benzo[a]pyrene), plant growth stimulators (e.g. choline chloride), antibiotics, hormones, radioactive isotopes and plastic substances (monomers). Climate and weather are also important factors, as well as soil type and pH, soil cultivation, fertilisation and conditions of crop storage after harvest. ∗
Biotic factors can have also a signiﬁcant impact on crop quality. The main biotic factors are cultivar choice, bacterial and fungal contamination (disease) and pest damage. Cultivars of the same crop species can differ signiﬁcantly in nutritive quality. For example, the content of βcarotene in carrots (Daucus carota L.) can vary between 7.19 and 13.84 mg g−1 depending on the cultivar.2 The main potential source of bacterial contamination in plant crops is animal manure used in organic farming. Contamination can take place via the roots or by water splashing onto the leaf surfaces. The most important organisms are several species of facultative anaerobic bacteria (Salmonella enterica, Escherichia coli O157:H7, Campylobacter spp., Listeria monocytogenes, Clostridium botulinum, Mycobacterium paratuberculosis), protozoa (Toxoplasma gondii), tapeworms, viruses and prions. The results obtained so far are contradictory. Some studies indicate...