ICAR AICE-JRF/SRF Food Toxicology, Contaminants & Allergens: practice questions

1 · Principles of toxicology: dose-response, NOAEL, ADI and TDI · medium

Why does JECFA express tolerable intakes for cadmium and methylmercury on a weekly or monthly rather than daily basis?

1. They are eaten only once a week in most diets around the world
2. Their toxicity tests were carried out only on a weekly dosing schedule
3. They accumulate, so long-term intake matters more than daily intake
4. They are excreted within a day, so daily limits would be meaningless

2 · Toxicity testing and risk characterisation · medium

EFSA considers a margin of exposure for a genotoxic carcinogen, based on an animal BMDL10, to be of low concern when it is at least:

1. 1
2. 10,000
3. 1,000
4. 100

3 · Natural toxicants in plant foods: glycosides, alkaloids, lectins and protease inhibitors · hard

Konzo, a paralytic disease in parts of Africa, is linked to:

1. Lead exposure from glazed pottery used to store water
2. Cyanide from poorly processed bitter cassava
3. Methylmercury exposure from freshwater fish
4. Fumonisin exposure from mouldy maize porridge

4 · Marine toxins and biogenic amines including histamine · hard

Why can the toxicity of histamine in spoiled fish exceed that of the same dose of pure histamine?

1. Cooking converts histamine into tyramine in the gut
2. Other amines block the enzymes that detoxify histamine
3. Histamine in fish is absorbed only after bacterial digestion
4. Fish proteins convert histamine into a more toxic alkaloid

5 · Mycotoxins: aflatoxins, ochratoxin, patulin, fumonisins and deoxynivalenol · hard

Why is no tolerable daily intake set for aflatoxin B1?

1. It never occurs in foods eaten by humans
2. It is always destroyed by normal cooking at home
3. It is a genotoxic carcinogen
4. Its toxicity is too low to require any limit

6 · Mycotoxins: aflatoxins, ochratoxin, patulin, fumonisins and deoxynivalenol · hard

Why are urinary or blood biomarkers such as aflatoxin-albumin adducts useful in exposure assessment?

1. They show which mould species grew in the stored grain
2. They show real absorbed exposure
3. They are cheaper than analysing a single food sample
4. They replace the need for any regulatory limits on food

7 · Process contaminants: acrylamide, PAHs, 3-MCPD, furan and nitrosamines · hard

Furan levels in jarred baby food can be reduced at home by:

1. Adding salt before serving
2. Heating it in an open pan
3. Heating the food in the sealed jar
4. Freezing the jar before opening it

8 · Migration of packaging contaminants · medium

Mineral oil aromatic hydrocarbons (MOAH) in dry foods such as rice come mainly from:

1. Stainless steel storage silos
2. Aluminium foil pouches
3. Glass jars with metal lids
4. Recycled paperboard

9 · Food allergens: major allergens, mechanisms and allergen management · medium

Which milk proteins are particularly stable to heat and so remain allergenic after processing?

1. Lactoferrin
2. Immunoglobulins
3. Caseins
4. Lactoperoxidase

10 · Food allergens: major allergens, mechanisms and allergen management · hard

Why are thresholds for food allergens hard to set for precautionary labelling?

1. Sensitivity differs greatly between allergic people
2. Allergens are destroyed by all processing, so no threshold exists
3. Allergen analysis cannot measure protein at any concentration
4. Allergic reactions depend only on body weight, not on dose