Q 2: chemical contamination of food Flashcards
adulterants
“adulterant” is a substance that is added to food but is not allowed. Economic considerations. An adulterant is a substance found in foods and beverages that is now allowed for legal or other reasons. Adulteration of has been going on at least since the 18th century, for example in Victorian England and the United States (likely many other places, including Canada). In London of the 18th century, wheat bread was often adulterated with chalk, alum and bone ashes to make it whiter, which was more desirable than brown bread in class-conscious England.
what are some example of adulterations
In the UK 18th and 19th centuries, manufactured foods were commonly adulterated as there were few controls on food content and quality
White Bread: alum, chalk, plaster of Paris
Beer: strychnine, ferrous sulphate, ground coriander seeds with Nux vomica and quassia
Jellies and sweets: bright colours from salts of lead, copper and mercury
Taiwan Food Scandal:Timeline
April 2011
Taiwan FDA found a phthalate (DEHP) in probiotic powder
May 2011
Started investigation to find products containing DEHP
Found a second company adulterating ingredient with phthalates (DEHP & DINP)
Traced to agents used as emulsifiers (up to 16 years in use!)
May 23: public announcement in Taiwan
May 28: announcement of plan to remove all adulterated products from shelves by May 31
Inspected 50,000 stores, removed ~29,000 items from ~4100 stores; all destroyed
May 2011
Informed international organizations and importing countries
22 countries imported products, including Canada, US, China, European Union, many others
INFOSAN: a global network of national food safety authorities under the WHO/FAO
RASFF: Rapid Alert System for Food and Feed of the European Union
Taiwan Gov. required certificates of analysis proving products free of adulteration before export
TFDA developed a method to rapidly screen samples for phthalates
Over 3000 samples were tested
Taiwan Food Scandal:What are Phthalates?
Colourless, oily substances added a diverse number of polymers and other products to make them more flexible and durable
DEHP: di-2-(ethylhexyl) phthalate
DINP: di-isononyl phthalate
DBP: di-butyl phthalate
Most commonly used in polyvinyl chloride (PVC) plastics up to 50% by weight
Also in personal care products
Concern about medical tubing and devices
Found in many products including materials that can come in contact with food»_space; migration to foods
Not approved as a food additive
Taiwan Food Scandal:How are we exposed to phthalates?
Dietary exposure major route for DEHP, DINP, due to:
food contact with packaging eg. PVC and paper (phased out or in progress)
production, processing storage, transport eg. vinyl gloves, PVC tanks for storage of beverages
Typical range 0.1 to 100 µg/kg in foods
Other routes include dermal and inhalation:
use of perfumes, shampoos, lotions, powders and other personal care products leading to absorption through the skin
inhalation of dust and fumes from flooring and other materials in the home and car - “out-gassing” and “new car smell” – important for lighter phthalates
“mouthing” of products by children; voluntary removal of phthalates from such products
Exposure especially important for pregnant women, nursing mothers, young children
Taiwan Food Scandal: Toxicity and Hazards of Phthalates
Reproductive and developmental toxicant
Health risks are due to long term “chronic” exposure to low concentrations
Those most at risk are developing fetus, nursing infants, developing children
Early exposure through mother’s placenta and mother’s milk
“Phthalate Syndrome”: disruption of the development of the androgen-dependent reproductive system, esp. males
Seen in studies with rats
Some association with abdominal obesity and insulin resistance (can lead to diabetes)
Some studies have found associations between increased exposure to some phthalates and liver tumours in rats
Classified as “possibly carcinogenic in humans” but studies inadequate
Taiwan Food Scandal: Adulteration of “Clouding Agents”
Manufacturers (two known) were adding phthalate-containing oils to prepare “clouding agents”
What are “clouding agents”?
powders or emulsions added to products like beverages
gives a more “natural” appearance, esp. when juice content of beverages reduced
prevents or masks sedimentation and “ringing”
usual formulation contains:
citrus or vegetable oil as the “clouding agent” itself
gum arabic as a stabilizer
a resin gum to prevent “ringing”
the adulteration occurred when palm oil was replaced or mixed with phthalate-containing oils
Taiwan Food Scandal: Adulterated Ingredients Widely Distributed
The adulterated clouding agents were widely spread through out the food industry Raw materials: spices concentrated juices jams & jellies End Products sports drinks tea drinks juice drinks jams & jellies & fruit pastes dietary supplements in capsules, tablets & powders ~900 food products from 435 suppliers
Taiwan Food Scandal: Maternal Exposure due to Phthalates from Adulterated Foods
Estimates of maternal exposure were made to assess possible adverse health effects (Yang at al, 2013)
Guidelines for daily intake range (0.02 to 0.06) mg/kg bw/day
“normal” dietary exposure is about 0.6 mg/day for an adult (US data)
equivalent for a 60 kg pregnant woman ingesting (1.2 to 3.6) mg/day
ingesting one 500 mL sports drink a day would be 7 mg/day, well above guidelines
one enzyme supplement tested had such a high amount in one capsule (2100 ppm) that 1 capsule a day would be 4x guidelines
a Taiwan study done 3+ yrs before found elevated daily intakes of phthalates
some levels of DEHP metabolites in maternal women higher than elsewhere
Taiwan Food Scandal: Canadian and American Response
US and Canada informed by Taiwan late May
Recalls on suspected ingredients and products from store shelves
US FDA (4 labs) and CFIA (Saskatoon Lab) collaborated with Taiwan FDA to validate analytical methods to support surveillance testing of imported ingredients and products
in 2011-2012, 275 samples were analyzed: bottled water, fruit juices, infant foods, jams & jellies, sports drinks, syrups, tea beverages: only 1 sample had detectable DEHP
More testing in following year, expanded to more types of samples
what is a contaminant
To some people, a “contaminant” is any substance they do not want to see in their food, allowed or otherwise.
“Contamination” can come in many forms:
Chemical
Microbiological
Physical
“Residues” are substances left in the tissues and fluids of animals after deliberate application
Focus in this lecture is on:
Adulteration of food ingredients
Response of regulatory authorities
“Food Fraud” versus “Food Crime”
what are residues
Residues” are substances left in the tissues and fluids of animals after deliberate application
Taiwan Food Scandal: The Rest of the Story
Identified Yu Chen Co as one supplier of adulterated clouding agent; used for 16+ years
Owners sentenced to prison terms (15 & 12 yrs) plus fines US$ 800K
identified Pin Han Co. as second supplier of adulterated products 13+ years
Owners sentenced to prison terms (13 & 10 yrs) plus fines US$ 167K
Food industry losses due to destruction of adulterated food and loss of sales US$ 667M
Great loss of prestige for “Taiwan Brand” as many countries demanded special testing and certification of purity
long term health effects, if any, not known and may take years to become apparent
Yang Ming-yu, the technical specialist from the Taiwan FDA who first found the phthalate adulteration became a national celebrity
Taiwan Food Scandal: Detection of Phthalate Contamination of Food
Reliable methods of detection needs to support regulations and survey food supply for levels of contaminants
Phthalates are a problem because they are “everywhere”
Common contaminants in laboratory supplies and materials that come in contact with samples or extracts during processing and analysis
Taiwan FDA provided a method that US FDA and CFIA evaluated and validated
Outline of quick method:
sample mixed with methanol in disposable tube
vortex, sonicate, vortex to extract phthalates
tube centrifuged to clarify solution
small volume transferred to vial for analysis
Contaminated Pet Food:Pet Deaths and Recalls
March 2007
Reports of pet deaths due to kidney failure associated with brand name pets foods with ingredients from Menu Foods
First recall of 60M units, 100 brand names from 2 plants in US
April 2007
US FDA received 15K complaints
Recalls expanded to products from the 3rd plant
130 brands from 5 suppliers
Recalls in US, Canada, Europe and S. Africa
Contaminated Pet Food:Sources and Contaminant
Initially associated with wheat gluten imported from China by ChemNutra of Nevada, supplied to Menu Foods and others
Initially identified as aminopterin by NY State Food Lab; but symptoms not consistent with substance
Later confirmed melamine in pet food, wheat gluten, tissues and urine
Also associated with some imported rice protein and corn gluten
What is Melamine?
A synthetic chemical used in industrial applications
Melamine, when reacted with formaldehyde, forms a thermosetting plastic
Was once considered as a non-protein source of nitrogen for cattle
No approved uses in food
Melamine can also enter food products through contact with melamine-containing products
Toxicity of Melamine
Symptoms associated with kidney damage and kidney failure
Melamine alone could not cause symptoms
Found “spoke-like” crystals of melamine and other substances, including cyanuric acid
Toxic effects associated with an insoluble crystalline complex of melamine and cyanuric acid
Why Add Melamine?
Melamine is a source of nitrogen
Cannot be distinguished from protein in commonly used analytical methods (eg. Kjeldahl)
Gives a false appearance of a higher level of protein
Produce cheaper or get a higher price for inferior product
Cyanuric acid also used for this purpose and had also been added to animal feed
Cyanuric acid also part of melamine scraps
Melamine in Animal Feed and Pet Food
Melamine found in urine of hogs in 3 US states; some meat had entered food supply
Also in chicken and fish
Melamine and cyanuric acid found in animal and fish feeds
Wheat gluten and rice protein concentrates (2−80) g/kg
Pet food: (9−2000) mg/kg
Hog feed: (10−60) mg/kg
Fish feed: (50−400) mg/kg
Source and Fallout
Traced to imported products from two Chinese factories
One US company used melamine as a binder in fish and livestock feed
After denying any connection, Chinese government starts own investigation
Government closes both factories and arrests executives
Head of Chinese State FDA sentenced to death for corruption
PS: After the fact, melamine implicated in animal deaths in SE Asia in 2004
Zheng Xiaoyu (centre), head ofChina’s State Food and Drug Administration from 1998 to 2005, reacts tohis deathsentence atthe Supreme People’s Court in Beijing.
China News Daily July 10, 2007
Melamine-Adulterated Milk and Milk Products
July 2008:
Incidence of kidney problems in infants in Gansu Province associated with Sanlu baby formula
Sept 2008 -
Company Fonterra of NZ, partner with Sanlu, informs NZ government which then contacts Beijing directly
A Chinese reporter breaks story; Sanlu admits milk powder contaminated with melamine
Testing showed milk powder from 22 companies tested positive for melamine
Melamine-Adulterated Milk and Milk Products
- Sept 2008
Production at Sanlu halted; 20 executives and managers arrested
2 babies confirmed dead Sep 15
Melamine found in liquid milk from 3 major dairies including Mengniu, largest milk producer in China
Melamine found in products such as baby food, milk chocolate, candies (M&Ms, Oreo cookies) sold in region
Melamine found in cookies sold in the Netherlands
Melamine found in eggs and egg powder likely from adulterated feed
Levels of Melamine In Adulterated Milk and Milk Products
Powdered infant formulas:
491 batches from 109 companies
69 batches from 22 companies tested positive: (0.09−620) mg/kg; one at 2,560 mg/kg
Liquid milk:
24 of 1,202 batches tested positive; highest 8.6 mg/kg
EU standards:
30 mg/kg migration from pkg
Destroyed products from China > 2.5 mg/kg
