Kadrin Meremäe

Dynamics of nitrate and nitrite content during storage of home-made and small-scale industrially produced raw vegetable juices and their dietary intake

The influence of storage conditions on nitrate and nitrite contents, pH, and total viable bacterial count of raw vegetable juices was studied. Three different types of juices from an Estonian small-scale producer and five different types of home-made juices were analysed. Analyses were performed immediately after opening the commercial juice packages and immediately after preparation of a home-made juice. Additionally, samples were taken after open storage of a juice at the refrigerator and ambient temperatures during 24 and 48 h. The biggest changes in nitrate and nitrite contents were found during storage of carrot, beetroot and radish juices. During 48 h of storage at ambient temperature, the mean increases of nitrite content in home-made carrot, beetroot and radish juices were from 0.1 to 187, from 2.1 to 578, and from 0.5 to 259 mg l−1, respectively. In the case of commercial lightly pasteurized products, the biggest increase of nitrite content, from 3.2 to 11 mg l−1, was found in red beetroot juice. After 48 h of storage at refrigerator temperature, the changes of nitrite and nitrate were smaller. In the case of consumption of 300 ml of home-made carrot juice, with a nitrate and nitrite content of 64 and 110 mg l−1, respectively, stored for 24 h at ambient temperature, the average intake was 8% and 846% of the acceptable daily intake of nitrates and nitrites, respectively. After consumption of 50 ml of the same carrot juice by children (1–2 years of age) the average intake of nitrates and nitrites was 7% and 733% of the acceptable daily intake, respectively.

Trans Fatty Acid Contents in Selected Dietary Fats in the Estonian Market

UNLABELLED In response to public concern, this study assessed the fatty acid (FA) composition of blended spreads, margarines and shortenings in the Estonian retail market in 2011. Special attention was paid to the trans fatty acids (TFA) composition. The changes in these characteristics of selected dietary fats in the market over recent years are also presented. Twenty-six edible fat brands, available in the Estonian retail market in 2011, were purchased and FA compositions were analyzed by chromatography. Saturated fatty acids (SFA) were the dominant group of FAs for all blended spreads (49.6 to 65.8%), and for the majority of shortenings (from 21.1 to 54.6%). Cis monounsaturated fatty acids (MUFA) were the dominant group of FAs for the majority of margarines, ranging from 25.3% to 50.5%. The total TFA for blended spreads varied from 1.18% to 9.08%, for margarines from 0.04% to 34.96% and for shortenings from 0.14% to 39.50%. Octadecenoic (C18:1) isomers were the main TFA found. Compared to 2008/2009, the industrially produced TFA (IP-TFA) content in several of the dietary fat brands was much reduced in 2011. This voluntary reformulation was probably a response to consumer demand associated with a public health campaign directed against IP-TFA in Estonian foods, and were mainly achieved by replacing TFA with SFA C12:0-C16:0. PRACTICAL APPLICATION Present paper is directed toward public health related institutions and food industries producing foods with potentially high contents of trans fatty acids (TFA). According to the public concern TFA content in domestic blended spreads has declined significantly over the past 3 y in Estonia. The reduction in the TFA content was achieved by replacing TFA with saturated fatty acids (SFA) (C12:0-C16:0). To shift food composition toward healthier product formulations, mandatory labeling of the sum of IP-TFA and SFA (C12:0-C16:0) was recommended.

Nitrate in leafy vegetables, culinary herbs, and cucumber grown under cover in Estonia: content and intake

The content of nitrate in leafy vegetables, culinary herbs, and cucumber was determined during the years 2006–2008. All samples of Estonian origin, except white cabbage, were grown under cover. Seasonal differences in nitrate concentrations were observed in lettuce and spinach. Nitrate concentrations in lettuce were 22% and those in spinach were 24% higher in winter crops compared with samples collected in summer. The mean nitrate level was 3023 mg kg–1 for fresh lettuce and 2337 mg kg–1 for spinach. On average, 11.6% of fresh lettuce and spinach samples nitrate concentration exceeded the maximum level specified in European Commission Regulation No. 1881/2006. The mean levels were 999 mg kg–1 for imported iceberg lettuce and 1287 mg kg–1 for frozen spinach, which are below the maximum European Commission limits. Parsley, dill, basil, thyme, and rucola contained high concentrations of nitrate from mean levels of 2134 mg kg–1 for parsley up to 8150 mg kg–1 for rucola. Mean nitrate concentrations ranged from 382 to 1115 mg kg–1 for white cabbage and Chinese cabbage, respectively. The per capita mean daily intake of nitrates related to the consumption of leafy vegetables, culinary herbs, and cucumber for the whole Estonian population was 31.3 mg day–1, which comprised 14.2% of the acceptable daily intake (ADI).

Antimicrobial Resistance Profiles of Campylobacter spp. Isolated from Broiler Chicken Meat of Estonian, Latvian and Lithuanian Origin at Estonian Retail Level and from Patients with Severe Enteric Infections in Estonia

The resistance patterns of Campylobacter spp. isolated from retail broiler chicken meat originating either from Estonia, Lithuania or Latvia collected in Estonia were determined. Additionally, in collaboration with the laboratories of several Estonian hospitals, antimicrobial susceptibility patterns were determined for Campylobacter isolates from patients with severe Campylobacter enteric infections. The isolates were identified at the species level by the PCR method. Respectively, 88.8% of the isolates were C. jejuni, and 11.2% were C. coli. In total, 126 Campylobacter isolates of broiler chicken meat and human origin were tested for minimal inhibitory concentrations (MICs) with the broth microdilution VetMICTH method (National Veterinary Institute; Uppsala, Sweden) for a total of six antimicrobials. Resistance to one or more antimicrobials was detected in 62 (63.3%) of Campylobacter broiler chicken meat isolates and in 20 (71.4%) of human‐origin isolates. Large proportions of the broiler chicken meat isolates were resistant to ciprofloxacin (60.2%). Multidrug resistance (i.e. to three or more unrelated antimicrobials) was detected in five (5.1%) C. jejuni isolates. Among the human isolates, 20 (71.4%) were resistant to fluoroquinolones, and two (7.1%) C. jejuni isolates exhibited multidrug resistance. The chicken meat isolates of Estonian origin were the most susceptible. However, a high proportion of fluoroquinolone‐resistant C. jejuni isolates were found in Latvian and Lithuanian products. The results of this study indicate that the problems caused by the inappropriate use of antimicrobials extend beyond the country in which a food originates; therefore, both domestic and international interventions and agreements are required to implement common policies on antimicrobial usage and to minimize the emergence of Campylobacter drug resistance.

Pesticide residues in Estonian local and imported food in 2008–2011

Abstract The use of synthetic pesticides is very common in conventional agriculture as plant protection measures and for improving storage of food. For increasing food safety, monitoring programmes are taking place in each European Union Member State and in Norway and Iceland every year. The monitoring aims to detect samples from food exceeding the maximum residue level (MRL) and provides data for an assessment of consumer exposure to pesticide residues. Results from Estonian national monitoring programme conducted by Veterinary and Food Board are presented in this paper, used to find out the differences in pesticide residue occurrences and MRL exceedances in local and imported food consumed in Estonia. In 2008, residues of one or more pesticides were found in 35–53% of the total analysed samples of fruits, vegetables and cereals. Imported food contained more pesticide residues compared to local food. MRLs were exceeded by 1.6% in 2008 and 2.3% in 2009 out of all samples, residues exceeding the MRLs were found in imported samples only. In 2010, 2.1% of total samples were above MRL. In 2011, 0.7% of total samples exceeded MRL which were of domestic origin. The highest MRL exceedances from the years 2008 to 2011 were propargite in beans with pods from Estonia over 10 times, chlormequat in grapes from India 7.9 times and trifluralin in tea from China 7.5 times. MRL was most frequently exceeded by dithiocarbamates, in 12 cases out of 22. The highest number of different pesticide residues in a single sample was 10 in apple from Belgium, 9 in mandarin from South Africa, 8 in strawberries from Spain and in apple from Poland. The results of monitoring programme show that local food contains less pesticide residues than imported food. By consuming food locally, it is possible to reduce the consumption of pesticide residues.

Comparative study of microbiological, chemical and sensory properties of kefirs produced in Estonia, Latvia and Lithuania.

In the current study the microbiological, sensory and chemical properties of 24 kefirs (12 producers) from Estonian, Latvian and Lithuanian retail market were determined using gas chromatography (GC), high performance liquid chromatography (HPLC-MS/MS-Q-TOF and LC-ion trap MS/MS), spectrophotometry and other methods. Antihypertensive, angiotensin-converting enzyme (ACE) inhibiting, antioxidant and antibacterial peptides were found in the kefir samples. According to the results of principal component analysis of 200 most abundant compounds obtained with HPLC-MS/MS-Q-TOF analysis, Estonian kefirs differed from the rest. Kefirs of Latvian and Lithuanian origin showed similarities in several characteristics, probably related to the starter cultures and technological processes. The fatty acids composition of all Baltic kefirs was uniform. The antioxidant capacity of the kefirs varied slightly, whereas intermediate positive correlation (r = 0.32, P < 0.05) was found between antioxidativity and total bacterial count. The lipid oxidation level, estimated as the content of linoleic and oleic acid primary oxidation products, oxylipins, was very low in all studied kefirs. Only one third of analysed kefirs met the requirements of the minimum sum of viable microorganisms, indicated in the Codex Standard for Fermented Milks.

Impact of Food Processing and Storage Conditions on Nitrate Content in Canned Vegetable-Based Infant Foods

The nitrate and nitrite contents were determined in canned vegetable-based infant foods of five varieties. Furthermore, changes in nitrate content during industrial processing were studied. Samples were taken from raw materials, homogenized mixtures, and final products after sterilization, and then analyzed for nitrate and nitrite content by high-pressure liquid chromatography. Processing steps preceding heat treatment, such as vegetable peeling and washing, decreased the nitrate concentrations in the range of 17 to 52%. During processing, the nitrate content in canned infant foods decreased 39 to 50%, compared with nitrate concentration in the raw-vegetable mixture. The final nitrate concentration in infant foods depends mainly on the initial nitrate content of the raw-vegetable mixture. The effect of storage time (24 and 48 h) and temperature (4 to 6 degrees C and 20 to 22 degrees C) on nitrate and nitrite content in opened canned infant-food samples was studied. After 24 h of storage at refrigerated and room temperatures, the mean nitrate content increased on average by 7 and 13%, and after 48 h of storage by 15 and 29%, respectively. The nitrite content in all analyzed samples was below the quantification limit. Storage requirements of industrial manufacturers must be followed strictly. Opened can foods, stored under refrigerated conditions, have to be consumed within 2 days, as recommended by manufacturers. The infant-food producers must pay more attention to the quality of raw materials. Nitrate content analyses should be added as compulsory tests to the quality assurance programs.

Antimicrobial resistance and multilocus sequence types of Campylobacter jejuni isolated from Baltic broiler chicken meat and Estonian human patients

Genotypes of Campylobacter jejuni in Baltic fresh broiler chicken meat and in Estonian human origin samples were determined by using MLST. We observed associations between clonal complexes, sequence types, and antibiotic resistance of C. jejuni isolates. The detection of high proportions of fluoroquinolone resistance among Latvian (100.0%) and Lithuanian (84.6%) origin broiler chicken meat C. jejuni isolates, found in this study, suggests the wide use of these antibiotics in poultry in these countries. MLST of 48 Baltic origin C. jejuni isolates revealed a total of 22 sequence types belonging to 13 clonal complexes. From the 13 assigned CCs and 22 STs, the most prevalent were ST-353 CC and ST-5 consisting of human, Latvian and Lithuanian chicken meat isolates. Among human and chicken meat isolates the resistance rate was 63.6 and 62.2%, respectively. ST-353 isolated from humans were more often resistant to nalidixic acid and ciprofloxacin than the other STs. Strain types ST-5, ST-50, ST-353, ST-354, and ST-429 isolated from poultry were more often resistant to both nalidixic acid and ciprofloxacin than the other STs. Furthermore, ST-353 and ST-354 isolated from poultry were more often resistant against tetracycline than the other STs. Fluoroquinolone resistance was significantly (P < 0.01) associated with ST-353 CC and ST-5 in comparison with all other CCs, STs. We found that three Estonian broiler isolates belonged to the novel ST-8188.The study indicates the potential public health concern posed by the very high fluoroquinolne resistance in Campylobacter jejuni found in Latvian and Lithuanian poultry meat.

Antibacterial and antioxidative properties of different parts of garden rhubarb, black currant, chokeberry and blue honeysuckle: Antibacterial and antioxidative properties of different parts of garden rhubarb, black currant, chokeberry and blue honeysuckle

BACKGROUND It is important to find plant materials that can inhibit the growth of Listeria monocytogenes and other food-spoiling bacteria both in vitro and in situ. The aim of the study was to compare antibacterial and antioxidative activity of selected plant-ethanol infusions: leaves and berries of blackcurrant (Ribes nigrum L.), berries of chokeberry (Aronia melanocarpa (Michx.) Elliott) and blue honeysuckle (Lonicera caerulea L. var. edulis); petioles and dark and light roots of garden rhubarb (Rheum rhaponticum L.) for potential use in food matrices as antibacterial and antioxidative additives. RESULTS The strongest bacterial growth inhibition was observed in 96% ethanol infusions of the dark roots of rhubarbs. In 96% ethanol, nine out of ten studied plant infusions had antibacterial effect against L. monocytogenes, but in 20% ethanol only the infusions of dark rhubarb roots had a similar effect. Chokeberry and other berries had the highest antioxidative activity, both in 20% and 96% ethanol infusions. CONCLUSION The combination of dark rhubarb roots or petioles and berries of black chokeberry, blackcurrant or some other anthocyanin-rich berries would have potential as both antibacterial and antioxidative additives in food.

Listeria monocytogenes'e levimus valmistoidus

Saabunud / Received 05.06.17 ; Aktsepteeritud / Accepted 15.06.17 ; Avaldatud veebis / Published online 15.06.17 ; Vastutav autor / Corresponding author: Mati Roasto ; e-mail: mati.roasto@emu.ee