7. HEALTH EFFECTS AND RISKS OF DIETARY EXPOSURE TO CONTAMINANTS IN FOOD CHAINS

7.1 Organization of monitoring activities

This subsystem has comprised four project parts since the year 2004. It has been carried out in 12 cities of the Czech Republic (see Tab. 3.1). The number of locations was selected so as to provide a uniform representation of the regions. The first part of the project deals with the monitoring of the occurrence of selected pathogenic bacteria in sampled foodstuffs. Bacterial strains isolated from food are subject to further qualitative analysis, including testing for antibiotic resistance and, in the case of listeria, quantitative detection of KTJ/g. The second part of the project deals with the monitoring of the incidence of toxic micromycetes (moulds) in sampled foodstuffs. Micromycete isolates are classified by genus and species and their toxicity (particularly production of aflatoxins and ochratoxins) is studied. The third part of the project focuses on the monitoring of foodstuffs based on genetically modified organisms in the Czech market. Inclusion of this part is a response to public demand for information about the situation in the Czech Republic and to the requirements from the EU and other international organizations. The presence of GM Soya, corn and tomatoes is monitored. The fourth part of the project deals with the monitoring of the population’s dietary exposure to selected chemicals. Food samples are collected in one location where they undergo standard culinary preparation and are subsequently analyzed for the content of selected chemicals. All results serve to estimate the exposure and to characterize the health risks associated with population nutrition in the Czech Republic. Since the year 2004, this part has been carried out in two-year intervals. It is not therefore assessed in the year 2004. The results for the years 2004 and 2005 will be published in 2006.

This chapter also contains a summary of alimentary infections and intoxications reported in the year 2004 and their development during recent years.

7.2 Alimentary infections and intoxications

Data on alimentary infections and intoxications are taken from the EPIDAT information system. The morbidity caused by the food-borne infections increased in the Czech Republic in the year 2004 compared to the previous year, a decrease was recorded only for viral hepatitis and shigellosis (however, no food-borne infection was reported for these two infections). When compared to an average year (1999–2003), a decrease was also observed for salmonellosis, listeriosis and alimentary intoxications (Fig. 7.1). Reported morbidity since the year 1995 is shown in Tab. 7.1. The development of morbidity rates for selected alimentary infections and intoxications is shown in Fig. 7.2.

Morbidity caused by salmonellosis and campylobacteriosis in the Czech Republic was again estimated to be among the highest in Europe. However, the quality of surveillance which is at a very good level in the Czech Republic and includes active screening must also be considered in international comparisons. Diseases caused by the S. Enteritidis (96.9 % of all cases) serotype were prevailing in salmonellosis. Neither the source nor the vehicle of the disease changed substantially compared to previous years. The hygiene service tried to identify the probable vehicle of infection in 12,472 of a total of 30,724 patients. The vehicles were eggs in 24 % of patients (virtually identical share of eggs from domestic breeds and from the distribution network), poultry meat in 22 % of patients, delicatessen products and mayonnaise in 11 % of patients and pastry and confectionery in 9 % of patients. Eggs played the most important role also in the category of ready-to-use meals (12 % of patients). In contrast, minimum morbidity was caused by the intake of milk or dairy products, fish, frozen products of any types, vegetables and fruits. A total of 1,782 people were infected in 85 epidemics. Egg-containing meals and food fried in breadcrumb batter rank among the meals with a high-risk for the development of epidemics. Higher morbidity or epidemics of salmonellosis occur in the territory of the Czech Republic more or less randomly in the event of non-compliance with technologies for food preparation. In the year 2004, higher morbidity due to salmonellosis was reported in Bohemia than in Moravia for the first time since 1985. Children aged 1 to 4 years were the most frequently affected age category. A total of 25 people died in relation to salmonellosis. Districts with the highest morbidity in the year 2004 were Plzeň-South, Znojmo, Cheb, Břeclav, Trutnov and Jihlava with the morbidity rate over 500 people per 100,000 inhabitants (Fig. 7.3). The seasonal occurrence of salmonellosis remained typical, with a higher occurrence throughout the second half of the year 2004 (Fig. 7.5).

Campylobacteriosis is the second most frequently occurring alimentary infection of bacterial origin in the Czech Republic after salmonellosis. The major etiological agent was Campylobacter jejuni (92.4 % of diseases). The steadily increasing morbidity (Fig. 7.2) had two main causes according to the available information. The first cause was an increased number of microbiological laboratories providing routine examination of samples for the presence of campylobacter, the second was the increased consumption of poultry meat, the major vehicle in Europe. The same increase was observed in many countries of the European Union. Diseases in the Czech Republic have a character of sporadic cases and family infections, as a total of 4 minor epidemics were reported in the year 2004 in diners after the consumption of chicken or pork meat. The highest morbidity rate exceeding 800 per 100,000 inhabitants was reported in the Moravian-Silesian Region (Fig. 7.4). The long-term morbidity rate in Moravia is markedly higher than in Bohemia. A total of 5 patients died. The seasonal character of the occurrence of campylobacteriosis basically corresponds to that of salmonellosis, with a peak occurrence in August (Fig. 7.5).

A decreasing trend of morbidity continued in shigellosis, where only one serious epidemic was reported from a recreational facility. A total of 60 % of diseases were caused by Shigella sonnei. No alimentary transmission was recorded. One third of cases were imported, most frequently from Egypt and Tunisia. A decreasing trend was also reported for morbidity due to viral hepatitis A (Fig. 7.1 and Fig. 7.2), also with an increasing share of imported infections, in particular from Egypt, Ukraine, and Romania (Fig. 7.6). All cases of listeriosis were sporadic, and neither the route nor the vehicle of transmission was determined. No epidemic of listeriosis has been described in the Czech Republic to date. Only 2 fatal cases were reported in 2004 (while 5 deaths annually were reported for previous years). A total of 1,743 cases were concluded as enteritis caused by E. coli, in particular in infants during their first year or months of life. No occurrence of severe clinical forms was reported. The most frequently identified serotypes were O 55 (322 cases) and O 26 (233 cases). No death was reported in relation to E. coli enteritis. The diseases did not have a seasonal character. The morbidity caused by yersiniosis increased (498 reported cases was the highest in the monitoring history). The highest morbidity during recent years was steadily diagnosed in North Moravia, followed by the Brno venkov (Brno Country), Uherské Hradiště, Český Krumlov, České Budějovice, Chomutov, and Louny districts. The age distribution of morbidity is similar to that of salmonellosis, however the cases have sporadic occurrence. The seasonal occurrence usually has its peak in October and November, and the major source of transmission is the consumption of pork. Cases of viral gastroenteritis were most frequently presented as infections of rotaviral etiology (79 %), which are usually transmitted by contact with the respiratory tract rather than by food; the number of cases has been increasing in the Czech Republic with the growing diagnostic capabilities of virological laboratories and growing interest of pharmaceutical firms in this potentially preventable infection. Rotaviral enteritis has a seasonal occurrence with prevailing morbidity during the winter months. The most frequently affected age group was children in their first year of life (502.7 per 100,000 children) and people working with children (a total of 28 epidemics were reported). The number of alimentary intoxications has been fluctuating year by year depending on how many epidemics are detected. A total of 4 epidemics were reported in 2004, the major vehicles were chicken, sausages and cakes.

7.3 Bacteriologic analysis of foodstuffs

Like in the years 1999–2003, the bacteriologic analysis of foodstuffs was focused on the monitoring of certain selected pathogenic agents in food products available in the market network. The selection of commodities to be examined was based on the “consumption basket” and concentrated on those food products that contributed to alimentary infections in the past whether in the Czech Republic or abroad. The spectrum of food samples to be examined was modified in 2004 compared to the previous years.

The main attention was focused on the demonstration of four etiological agents – causing important alimentary diseases: Salmonella spp., Campylobacter spp., Listeria monocytogenes, and E. coli O157. Except for salmonella, the other agents were monitored only exceptionally within the routine inspection of food safety and therefore virtually no information is available on their incidence in the respective commodities in the Czech Republic.

The microbiological analysis was conducted according to standards valid in the Czech Republic. The isolates were confirmed using biochemical analysis and a serotype was determined for salmonella and Listeria monocytogenes. Salmonella isolates were also monitored for the resistance to antibacterial agents, and phage typing was performed for S. Enteritidis (SE) and S. Typhimurium (STM).

A total of 681 samples of food were examined, including various types of meats and giblets, fish, poultry and raw products, eggs, meat, dairy, delicatessen and confectionary products, candies, vegetable, dry shell fruits and spices. Positive findings were made in 11 samples. Salmonella was isolated in particular from the samples of poultry meat, pork liver, fish meat and fish products and eggs. The most frequently isolated serotypes of salmonella were S. Entertidis (9x) and S. Typhimurium (2x). Based on phage subtyping, the SE isolates were classified as phage types PT 6b, PT 7, PT 8 (5x), PT 10 and PT 14b. STM isolates were classified as phage types DT104 and DT106.

The demonstration of campylobacter was performed in 108 samples of various types of meat and giblets, frozen vegetables and meat products. Positive findings of Campylobacter spp. were made in 14 samples. C. jejuni was detected in 9 samples of poultry meat and giblets and in 1 sample of pork liver, while C. coli was isolated in 4 samples of poultry meat and giblets.

A total of 657 samples was examined for the presence of Listeria monocytogenes (LM), including various types of meats and giblets, dairy, meat, fish, delicatessen and confectionary products, candies, vegetables, dry shell fruits, spices and raw products. A positive finding of LM was made in 32 samples. LM was demonstrated in the samples of various meats, including poultry (10x), meat products (10x), frozen vegetables (6x), choice salads with mayonnaise (4x), Niva cheese (1x) and raw products (1x). The most frequently detected serotype was 1/2. LM was enumerated per 1 g of food in samples of food ready for consumption, and 1 x 103 KTJ/g was found in the sample of bacon, 5.8 x 103 KTJ/g in sliced poultry ham, and 5 x 101 KTJ/g in Russian salad sample.

Presence of E. coli O157 was examined in 36 samples of food (poultry and pork liver). The pathogenic agent was found in neither sample.

7.4 Mycological analysis of foodstuffs

The monitoring of the incidence of toxinogenic micromycetes (moulds), producers of aflatoxins and ochratoxin A, in selected food products continued in 2004. Specialized mycological examination focused on the description and characterization of hazards associated with the occurrence of toxinogenic micromycetes in foodstuffs. Given the detailed mycological monitoring of toxinogenic filamentous micromycetes Aspergillus section Nigri, producers of ochratoxin A, the number of food samples, previously collected for a single year analysis, was divided into 2 years (2004–2005). With respect to sample collection, the year 2006 will proceed according to the traditional scheme of the “MYKOMON” study from previous years. A total of 13 types of commodities were sampled from 12 sampling locations in 4 sampling dates in the Czech Republic during the year 2004, which totals for 156 samples of food.

Qualitative and quantitative data was obtained on the incidence of toxinogenic mikromycetes (producing aflatoxins and ochratoxins A) in the foodstuffs in the Czech Republic. The total micromycete count was determined in selected foodstuffs (KTJ/g of food) and the mycological profile was identified. The incidence of monitored toxigenic micromycetes was expressed as a contamination index (Ik) – in other words, the ratio of potentially toxic micromycetes (KTJ/g food) to the overall micromycete count (KTJ/g).

Potentially toxinogenic micromycetes Aspergillus flavus, producers of aflatoxins, were detected in a total of 7 samples (29 %) of the following foodstuffs: rice and black pepper. From the isolated strains of Aspergillus flavus, 3 strains (43 %) were classified as toxinogenic. Their toxinogenicity was confirmed by determination of aflatoxin production on the nutrient medium (YES medium). The results for the entire period of monitoring from the year 1999 are summarized in Fig. 7.7.

In addition, the presence of toxinogenic micromycetes Aspergillus tamarii, producers of aflatoxins, was detected in 1 sample (8 %) of black pepper. This strain was not classified as toxinogenic as no production of aflatoxins was detected on the nutrient medium (YES medium).

Aflatoxin B1 was detected in 3 samples (25 %) of sweet pepper (arithmetic mean 3.6 µg/kg, maximum 8.0 µg/kg). Aflatoxin G1 was detected in 1 sample (8 %) of sweet pepper in the concentration of 1.0 µg/kg.

Potentially toxinogenic micromycetes Aspergillus section Nigri (ochratoxin A producers) were detected in 11 samples (30 %) of the following foodstuffs: rice, sweet pepper, black pepper. Isolates of filamentous micromycetes Aspergillus section Nigri were stored in 30% aqueous glycerol solution at – 71 °C for further analysis in NIPH – Centre for the Hygiene of Food Chains in Brno.

As in previous years, Penicillium crustosum strains (potential producer of the mycotoxin penitrem A) was detected in 33 % of walnut samples.

7.5 Incidence of genetically modified foods on the Czech Republic’s market

The year 2004 was the third year of the study which focuses on monitoring of foodstuff samples taken from the market network, to find out whether they are not manufactured from genetically modified organisms. As in previous years, samples were taken in the market network in four different collection dates at 12 locations in the Czech Republic. The following 4 kinds of food were analyzed: tomatoes, Soya beans, Soya products, and corn flour. A total of 192 samples were collected (48 samples of tomato, 48 samples of Soya beans, 48 samples of Soya products, and 48 samples of corn flour).

To detect GMO and GMO-containing new food products, the samples were analyzed by polymerase chain reaction (PCR) screening and identification method, immunochemical method (ELISA) and quantification, real-time PCR method (RT-PCR). The results are shown in Tab. 7.2a.

In total, 19 samples of Soya products and 2 samples of Soya beans were found positive using the RT-PCR method. The quantity of Roundup Ready Soya (RRS) present in the Soya beans and Soya products was lower than 0.9 % in all cases. According to the EU regulations 1829/2003 and 1830/2003, foods containing more than 0.9 % GMO must be labeled. The content under 0.9 % is considered to be accidental or technically unavoidable admixture of GMO. As the GMO content in the examined foodstuffs was lower than 0.9 %, the food products do not need to be labeled on the package, unless GMO has been used in the food intentionally. A comparison between the results of GM Soya determination in food products using RT-PCR method in the years 2002–2004 is shown in Tab. 7.2b.

The results obtained demonstrate that foods containing Roundup Ready Soya (40-3-2) are available on the Czech market (40-3-2), which has been permitted in the Czech Republic as a new food product, however, there is a decreasing share of foodstuffs that must bear a mandatory labeling (see Fig. 7.8).

7.6 Partial conclusions

The results of microbiological analysis suggest which commodities in the market network are most frequently contaminated with pathological agents and serve to obtain a more precise conception of the causes of alimentary infections.

Results from the monitoring of toxigenic micromycetes in foodstuffs confirm the assumption of a higher incidence of dangerous mycotoxins in certain types of foodstuffs.

It is evident from the results of monitoring GMO in foodstuffs that the rate of detection of GM RR Soya in the samples of Soya beans and Soya products was higher in 2004 than in previous years. However, this poses no known risk in terms of health safety. No new scientific information was published during 2004 that would describe any health risk resulting from the use of approved GMO foodstuffs in the EU/Czech Republic.

Detailed results from the monitoring presented in chapters 7.3 through 7.5 are available in the Expert Report on the Subsystem 4, Health effects on the human body caused by contaminants of food chains: bacteriologic and mycological analysis of foodstuffs and monitoring of the incidence of GM raw materials in foodstuffs, NIPH Prague at www.chpr.szu.cz.

Tab. 7.1 Incidence of selected notified alimentary diseases in 1995–2004
(number of cases per 100,000 population)

ICD

Diagnosis

1995

1996

1997

1998

1999

2000

2001

2002

2003

2004

A02

Salmonellosis

528.1

466.7

387.4

493.7

436.1

391.7

326.6

274.1

263.7

301.2

A04.5

Campylobacteriosis

29.3

22.1

35.2

53.8

95.7

164.7

210.5

227.5

196.7

249.9

A03

Shigellosis

16.9

7.8

6.0

5.0

5.1

5.3

3.4

2.8

3.7

3.2

B15

Viral hepatitis A

10.6

20.2

11.6

8.8

9.1

6.0

3.2

1.2

1.1

0.7

A04

E. coli enteritis

9.1

6.0

11.5

10.1

11.8

11.5

11.9

15.7

15.5

17.1

A05

Alimentary intoxication

8.9

6.0

3.2

4.8

5.1

10.6

6.7

2.6

0.6

1.9

A04.6

Yersiniosis

2.1

1.0

1.5

1.5

2.1

2.2

2.9

4.0

3.6

4.9

A08

Viral intest. infection

1.9

7.7

4.6

8.9

7.9

11.7

11.3

23.3

20.6

35.2

A32

Listeriosis

0.1

0.1

0.1

0.1

0.1

0.2

0.2

0.2

0.1

0.2

ICD – International classification of diseases (10. revision)

Tab. 7.2a Results of foodstuff sample survey of GMO detection, 2004

Material

No. of samples

Positive findings (%)

Positive findings (< 0,9 %)

Soya products

48

19 (39.6)

19 (39.6)

Soya beans

48

2 (4.2)

2 (4.2)

Tomatoes

48

0

0

Corn flour

48

0

0

Total

192

21 (10.9)

21 (10.9)

Tab. 7.2b Presence of Roundup Ready Soya in foodstuff in 2002–2004

Foodsuff

Positive findings (no./%)

Positive findings (< 0.9 %)

Positive findings (> 0.9 %)

2002

2003

2004

2002

2003

2004

2002

2003

2004

Soya beans

6/12.5

1/2.1

2/4.2

4

1

2

2

0

0

Soya products

18/37.5

5/10.4

19/39.6

9

4

19

9

1

0

Total

24/12.5

6/3.1

21/10.9

13

5

21

11

1

0


Fig. 7.1 Notified cases of alimentary diseases in 2004 in comparison with the average year levels (1999–2003)
Fig. 7.2 Trend of notified alimentary infections and intoxications in 1995–2004
Fig. 7.3 Salmonellosis incidence rate in districts, 2004
Fig. 7.4 Campylobacteriosis incidence rate in districts, 2004
Fig. 7.5 Salmonellosis and Campylobacteriosis, seasonality by month of affection, 1997–2004
Fig. 7.6 Share of imported affections on the total Viral hepatitis A morbidity
Fig. 7.7 Frequency of findings of Aspergillus flavus strains in various foodstuff types, 1999–2004
Fig. 7.8 Frequency of positive findings of GM Roundup Ready Soya, 2002–2004
Distribution as per limit for obligatory foodstuff marking (0.9 % GM content) and bound of determination of RT-PCR method

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