Individual solutions to meet food safety requirements

Access to safe and nutritious food is crucial for maintaining life and health. According to the World Health Organization, around 600 million people worldwide fall ill each year from the consumption of contaminated food, of which 420,000 die as a result. Almost a third of these deaths affect children under the age of five. Most often, diarrhoeal diseases are the result of the consumption of contaminated food. Food supply chains often exist across national borders. Good cooperation between governments, manufacturers and consumers, combined with adequate testing for contamination by food pathogens and toxic compounds, as well as nutrient content, can contribute significantly to food quality and safety.

The food chain usually begins on a farm within the agricultural sector. From here, most food first goes to food and beverage manufacturers for further processing and then to retailers or consumer services until it finally reaches the end consumer. On this path from producer to consumer, food passes through many hands, such as wholesalers and intermediaries, transport or storage companies.

However, food safety strategies are not limited to the safety of food intended for human consumption, but also include feed, animal health and protection, and plant protection. Throughout the process from producer to consumer, it must be ensured that food is fully traceable, in particular via international transport routes.

Analytik Jena GmbH and its parent company Endress+Hauser offer products that meet the requirements of the food industry and the relevant regulations with their high standards. From primary agricultural production to processing to the consumer, it is essential that the standards for food quality and safety are always met, which is possible thanks to the combined use of products from Endress+Hauser and Analytik Jena.

Agricultural economicsPrimary agricultural production - Soil quality and fertilisers

The quality of the soils and fertilizers used to support the growth and variety of agricultural products intended for consumption plays a central role in the quality of the food offered on supermarket shelves. The analytical instruments from Analytik Jena are specially designed to meet the high requirements of the industry and enable the fast and comprehensive chemical investigation of soils and fertilizers. This includes, for example, the determination and quantification of toxic metals such as cadmium, lead, arsenic, mercury and chromium, which could reach the end consumer via the food.

The devices of the PlasmaQuant family for elemental analysis using ICP-OES and ICP-MS from Analytik Jena reliably measure toxic metals even in the ultratrace range and thus far below the values applicable in Europe and prescribed by other important regulations. The large linear range of these devices also allows the determination of numerous vital elements and nutritional components, such as calcium, magnesium, potassium, iron, selenium, zinc, copper, sulfur and phosphorus, to name but a few.

For laboratories with smaller sample volumes, lower requirements for the elements to be determined, or a lower budget, atomic absorption spectrometers (AAS) offer a cost-effective alternative that requires a lower capital outlay compared to ICP techniques. Combined flame and graphite furnace systems are also able to determine main, secondary and trace elements, albeit with compromises in sample analysis time.

Measuring the health of soils where food and feed crops are grown is crucial not only for maximizing yields, but also for complying with the prescribed limits for the concentration of toxic metals. The same applies to fertilizers, because here, for example, the right NPK ratio (i.e. nitrogen, phosphorus and potassium) as well as other essential elements are decisive for obtaining the best mixture for certain plants. At the same time, however, fertilizers are also a potential source of toxic metals.

Table 1: Measurement of different elements in soil samples with the PlasmaQuant PQ 9000 ICP-OES

Element	Line	Soil digestion content in mg/kg		RSD	Detection limit
Element	nm	Reading	Expected value	%	mg/kg
Ace	188,9790	8,23 ± 0,04	8,5	0,1	0,05
Ca	315,8869	41.800 ± 100	42.000	0,3	-
Compact disc	214,4410	0,233 ± 0,04	0,24	4	0,015
Compact disc	228,8018	0,232 ± 0,07	0,235	2	0,03
Cr	267,7160	27,45 ± 0,05	27,6	0,6	0,04
Cu	327,3960	17,5 ± 0,1	17,2	0,2	0,1
K	766,4911	1.890 ± 30	1.900	1	-
Mg	279,0777	5.960 ± 10	6.000	0,1	-
Ni	231,6036	24,73 ± 0,03	24,50	0,1	0,05
P	177,4340	920 ± 10	900	1	-
Pb	220,3534	23,4 ± 0,2	23,0	0,3	0,35
Tl	190,7960	0,17 ± 0,06 (< LOQ)	-	18	0,075 (LOQ 0,22)
Zn	206,2000	60,4 ± 0,2	60,0	0,2	0,025

The content of organic carbon in soils and fertilizers is also an important factor, as the organic compounds are biodegraded by microorganisms. Organic acids are formed, which contribute significantly to the mobilization of heavy metals through complex formation, which then reach the deeper layers of the earth and groundwater. A measuring device for elemental analysis such as the multi EA 4000 from Analytik Jena enables the fully automatic measurement of all inorganic carbon (TIC – Total Inorganic Carbon), total carbon (TC – Total Carbon) and total organic carbon (TOC – Total Organic Carbon) in fertilizers and soils.

Table 2: Results of TIC, TC and TOC determination in fertilizer and soil samples

Sample	TIC [%]	TC [%]	TOC [%]
Dolomite	12,41 ± 0,35	12,24 ± 0,35	0,00 ± 0,00
Calcium sulfate	0,82 ± 0,05	0,96 ± 0,05	0,20 ± 0,05
Fertilizer grains	0,57 ± 0,06	0,69 ± 0,03	0,13 ± 0,05
Reference material for soil samples	11,8 ± 1,54	55,6 ± 2,24	46,7 ± 2,81
Soil reference values	12,0	55,8	47,0

The determination of microbial biomass and dissolved organic matter (DOM) in soils is an essential parameter for the characterization of cultivated areas in agriculture. They form the basis for the nutrition of microorganisms. Therefore, fumigated and ungassed soil samples are replaced by aqueous saline solutions (e.B 0.5 mol K ₂ SO ₄ ) and determines the extractable organic carbon (EOC) and extractable nitrogen (EN) with a TOC/TN analyzer such as the multi N/C 2100S or the multi N/C 3100 from Analytik Jena.

Table 3: Results of the determination of non-purgeable organic carbon (NPOC) and total nitrogen (TN) in soil samples

Name of the sample	NPOC [mg/L]	NPOC RSD [%]	TN [mg/L]	TN RSD [%]
Soil sample 1	1,56 ± 0,02	2,2	0,497 ± 0,003	1,1
Soil sample 2	11,6 ± 0,1	1,3	4,81 ± 0,02	0,9
Reference material for soil samples	5,26 ± 0,04	1,6	1,22 ± 0,01	0,8
Soil reference values	5, 18		1,30

Fodder

The term feed usually refers to food and fodder crops fed to animals and includes, inter alia, hay, straw, silage, pressed or pelleted feed, oils and mixed rations, as well as outgrowth and legumes. Feed grain is the most important source of feed worldwide. Grain maize as energy flour and soy flour as a protein supplier are the two most important feed grains. Other feed grains include wheat, oats, barley and rice.

Feed plays a central role in the daily intake of nutrients and fibres and thus in maintaining the health of farm animals. In addition to the organically bound elements hydrogen, carbon, nitrogen and oxygen, which are primarily obtained from air and water, there are more than 30 other dietary elements required for the correct functioning of living organisms.

Phosphorus, potassium and sulfur are considered so-called macronutrients in all living organisms. While calcium and magnesium are needed in relatively large quantities, the remaining minerals are required in significantly smaller quantities or only as trace elements. Of the trace elements needed for normal plant growth, also known as micronutrients, boron, copper, iron, manganese, zinc and molybdenum are among the most important and currently best researched. The remaining micronutrients, meanwhile, have a significant impact on the metabolism of animals and humans, while chloride and sodium are important for plant growth.

Calcium, for example, is the main component of bones and teeth and is responsible for their strength, and also supports blood clotting and the proper functioning of the nervous system. Calcium deficiency can lead to osteoporosis, metabolic disorders and other problems in humans and animals. Magnesium is important for ruminants to prevent grazing tetany, while selenium is a significant factor in cow fertility. A lack of manganese can lead to skeletal malformations in animals and inhibit the production of collagen during wound healing.

In contrast, toxic elements have a direct negative effect on organisms. Examples include beryllium (Be), antimony (Sb), bismuth (Bi), barium (Ba), uranium (U), aluminum (Al), thallium (Tl), mercury (Hg), cadmium (Cd) and lead (Pb). Toxic elements tend to accumulate in organs such as the liver, kidneys, pancreas and lungs. Cadmium, for example, causes damage to the kidneys and cardiovascular disease, while lead attacks virtually every organ and body system, but especially the brain and nervous system, with children being the most susceptible to it. According to the World Health Organization (WHO), mercury is one of the ten most toxic chemical substances, especially in the form of methylmercury. It has toxic effects on the nervous, digestive and immune systems, as well as on the lungs, kidneys, skin and eyes. Exposure to methylmercury occurs mainly through the ingestion of contaminated fish and seafood.

With regard to the upstream processes in the food supply chain, and in particular to the agricultural industry, it is clear that a balanced composition of feed contributes to animal welfare and health in terms of macrominerals and trace elements. Accurate measurement of the elemental composition of food and agricultural products is essential to ensure product safety and sufficient nutrient content. However, since concentrations are usually in the dissolved state in the lower ppb to upper ppm range, optical emission spectrometry and mass spectrometry with inductively coupled plasma (ICP-OES and ICP-MS) provide fast, reliable and routine sample analysis over a wide concentration range.

Table 4: Results for an in-laboratory reference material for hay samples analyzed after 400-fold dilution using ICP-MS

Element	Measured value (mg/kg)	Expected value (mg/kg)
²³ Well	0,33 %	0,34 %
²⁴ Mg	0,19 %	0,21 %
³¹ P	0,37 %	0,39 %
³⁹ K	0,34 %	0,35 %
⁴⁴ Ca	0,54 %	0,57 %
⁵² Cr	1,8	1,9
⁵⁵ Mn	79,1	81,9
⁵⁶ Fe	498	531
⁵⁹ Co	0,18	0,19
⁶⁰ Ni	1,53	1,61
⁶⁵ Cu	7,5	7,8
⁶⁶ Zn	33,0	34,9
⁷⁵ Ace	0,27	0,28
⁷⁸ Se	0,047	0,049
¹¹⁴ Compact disc	0,079	0,083
²⁰² Hg	0,014	0,015
^206-208 Pb	1,14	1,19

Table 5: Results for a reference material for feed samples analysed after 2000-fold dilution using ICP-OES

Element	Line (nm)	Measured value (mg/kg)	Expected value (mg/kg)
Al	396,152	0,20 %	0,21 %
Ca	317,933	12,2 %	12,1 %
Cu	327,396	0,22 %	0,20 %
Fe	238,204	0,63 %	0,64 %
K	766,491	11,0 %	11,2 %
Mg	285,213	3,99 %	3,99 %
Mn	259,372	0,14 %	0,14 %
Well	589,592	3,25 %	2,98 %
P	178,224	10,6 %	10,5 %
S	180,672	4,11 %	3,84 %
Zn	206,200	4,32 %	4,58 %
B	249,773	116	120
Co	228,615	< NG	< 20
Cr	267,716	8	< 32
Mon	202,030	6,2	< 20
Ni	231,604	6,4	< 50
V	292,464	< NG	-

MercuryMercury in dairy and fish products

Accelerated industrial and agricultural development in recent decades has been accompanied by a significant increase in exposure to toxic elements such as mercury. Farm animals kept on free pasture land are good indicators of pollution from heavy metals and at the same time a potential source of pollution.

Mercury is known to accumulate in organisms. For example, high concentrations are found in fish, especially fish species at the upper end of the food chain, such as tuna, sharks, mackerel or swordfish. Mercury is also present in dangerously high concentrations in the more toxic form of methylmercury. In addition to fish and other seafood, however, dental amalgam fillings are a major source of mercury exposure in humans.

It is generally known and recognized that mercury impairs the neurological development of the brain – especially in young children. Infants who are breastfed are particularly susceptible to this. This is especially true in areas where a lot of fish and seafood is consumed, as methylmercury is excreted in breast milk. Infants who are breastfed over a long period of time may therefore be at a higher risk of being exposed to toxic methylmercury. In contrast, a 1991 study by Hapke found that cattle can demethylate mercury in their rumen and thus absorb less mercury. Therefore, beef and cow's milk have much lower concentrations of mercury.

Determination of mercury in milk powder and tuna

A contrAA Continuum Source atomic absorption spectrometer (AAS) from Analytik Jena was used to determine low concentrations of mercury in milk powder, tuna and fish protein.

In combination with the HydrEA accessories, the contrAA 800 AAS enables the ultratrace determination of mercury with detection limits in the ppt range and thus far below the concentrations in dairy products. In addition, with the exclusive solid AA accessories in combination with the graphite furnace system contrAA 800 G, the direct examination of the fish protein without sample digestion is also possible.

Table 6: Determination of trace Hg in dairy and fish products with the AAS contrAA

Element	Wavelength [nm]	Sample	Concentration [µg/kg]
Hg	253,652	Lactose powder	< 2
		Fresh tuna fillets	372 ± 15
		Freeze-dried tuna	1.981 ± 77
		DORM-2*	4.330 ± 90

* Certified reference material for fish protein, certified content: 4,640 ± 260 μg/kg

ArsenicArsenic ArsenicArsenic - Identification of arsenic species

Arsenic (As) is a naturally occurring element and is found in the air, soil, water and food. However, human activities, such as the combustion of coal and other fuels or the use of arsenic compounds in medicine as well as in plant and wood preservatives, have further increased the input.

In addition to drinking water consumption, the consumption of rice is an important source of arsenic, affecting around three billion people. Global rice consumption has risen from 156 million tonnes in 1960 to 496.6 million tonnes in 2013. In addition, studies show that arsenic exposure is significantly more critical in rice than in other foods. For example, the arsenic concentration in rice is ten times higher than in wheat or barley. The increased arsenic content is due to the fact that rice is the only major cereal grown on flooded land. Due to the arsenic contained in the water, high arsenic concentrations are therefore found near the roots. In addition to direct intake through consumption, the use of rice straw as animal feed also increases the risk of arsenic contamination.

According to the guidelines of the World Health Organization, the maximum permissible limit for arsenic content in drinking water is a total of 10 ng/ml. Although there are no such limits for food products, the Food and Agriculture Organization of the United Nations (FAO) and the World Health Organization (WHO) recommend a maximum intake of 15 μg per kilogram of body weight per week.

Inorganic arsenic is associated with numerous adverse health effects, especially when stressed during pregnancy, as well as in infancy and infancy. The U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition (FDA) has identified a link between longer-term exposure to arsenic from rice and rice products and cancer risk, including lung, liver and kidney cancer, as well as non-carcinogenic health effects, including cardiovascular disease, diabetes and neurological cancer. Impairments, noted.

However, the toxicity of arsenic depends not only on the total concentration, but also on the respective chemical form, as these differ in terms of mobility, toxicity and bioavailability. Soluble trivalent inorganic arsenic compounds (AsIII) and pentavalent arsenic (AsV) are the most toxic forms and can be quickly absorbed by the body. After ingestion, the inorganic arsenic in the blood is metabolized by the reduction of AsV to AsIII and absorbed by tissue cells, predominantly in the liver. Other forms frequently ingested through consumption are, for example, organic monomethylarse (MMA) and dimethylarses (DMA), which have a much lower toxicity. Inorganic arsenic is also largely methylated by intracellular oxidative addition to MMA and DMA and the metabolic products are then excreted primarily in the urine.

Rice usually contains a high proportion of inorganic arsenic compounds, which underlines the importance of arsenic speciation for the study of rice samples. Studies have shown that thorough washing and boiling in plenty of water can reduce the amount of arsenic in ready-to-eat rice. However, if the rice is washed and boiled with arsenic-contaminated water, this can further increase the arsenic load.

High-performance liquid chromatography (HPLC) in conjunction with ICP-MS is the recommended device configuration for the determination of arsenic species in food and beverages. HpLC enables the rapid separation of all important arsenic species in less than ten minutes, while PlasmaQuant MS for Analytik Jena's ICP-MS enables ultratrace determination of up to <0.4 μg arsenic per kilogram of rice.

Table 7: Determination of arsenic species in basmati rice by HPLC-ICP-MS

	AsIII	DMA	MMA	AsV	Sum of 4 species
Medium	162	60	n. d.	95	317
% RSD	4,3	6,7	--	11,2	5,7

Species referenceSpecies detection Species referenceSpecies detection - Identification of animal species

The identification of undeclared components of animal origin is required to meet international regulatory standards for compliance with religious commandments and health protection laws. The adulteration and substitution of food is of concern for various reasons, such as general health, religious factors, authenticity or unfair competition in the food industry. One of the most practical methods for reliably identifying animal species in processed foods is through the genetic information contained in DNA. This is done, for example, in determining the origin of gelatin in gummy bears, the different types of meat in minced meat or the identification of any traces of pork in rice.

The InnuPure C16 touch from Analytik Jena for fully automatic nucleic acid extraction in combination with the innuPREP Food DNA Kit-IPC16 extraction kit enables the automatic preparation, isolation and capture of DNA using pre-filled and sealed reagent plastics. The eluates are analyzed using polymerase chain reaction (PCR) in real time with the powerful thermocycler qTOWER³, using the innuDETECT Species ID assays to detect goat, sheep, beef, pork, horse, donkey and turkey DNA.

Polymerase chain reaction (PCR) is a technique used in molecular genetics that allows the study of short DNA or RNA sequences even in samples containing only the smallest amounts. PCR is used to reproduce and duplicate selected DNA segments for analysis purposes. The real-time PCR results shown in Table 8 and the amplification plots in Figures 9a, 9b and 9c indicate the actual animal origin species of five different cheeses examined for the origin of the milk, including cow, goat and sheep, and the results compared with the corresponding information on the original packaging. For four of the five cheeses, the analysis identified a different milk source than the origin declared on the packaging.

Table 8: Declared against determined original milk source of five different cheeses

No.	Declared milk source	Determined origin
No.	Declared milk source	Goat	Sheep	Cow
1	Goat	x		x
2	Goat, sheep, cow	x	x	x
3	Sheep	x	x	x
4	Buffalo	x	x	x
5	Cow	x		x

PathogenicDetection of food pathogens

Foodborne diseases are extremely diverse. They pose an increasingly serious public health problem, are due to the consumption of food contaminated with microorganisms and can occur at any stage of the entire food production from producer to consumer. The most common symptoms seen in foodborne illness are infections or irritation of the digestive tract and usually include vomiting, diarrhea, abdominal pain, fever, and chills. However, the consumption of contaminated foods can also lead to other symptoms up to multiple organ failure and even cancer. Diarrhea is the most common disease. Every year, more than 550 million people fall ill and more than 230,000 people die. Food security, nutrition and security of supply are inextricably linked to unsafe food, creating a vicious cycle of disease and malnutrition or malnutrition that is most likely to affect infants and young children, as well as the elderly and sick.

DNA extraction using SmartExtraction technology ensures even faster extraction of foodborne pathogens, including Listeria, Salmonella, and Koli and Campylobacter bacteria, while TaqMan-based® innuDETECT pathogen assays enable highly reliable and routine detection of food pathogens.

Table 9: Concentrations of pathogens after standard cultivation (1 ml used for extraction) and measured Ct value

No.	cfu/ml	Ct value
1	8,3 x 10 ⁸	14,08
2	8,3 x 10 ⁷	19,03
3	8,3 x 10 ⁶	22,22
4	8,3 x 10 ⁵	27,27

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