Transcript Safety of dairy products

Dr. A.M. Mortazavian
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Introduction
Milk and milk products are indispensable components of the food supply chain
Dairy products are consumed by all population groups
Possible contamination by either a microbiological, chemical or physical hazard would affect a
large population.
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Food safety hazards in dairy products
Physical
Chemical
Biological
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Physical hazards
Consist of detectable pieces of non-food material (foreign bodies) such as glass, wood, metal pest, plastic
which have found their way into food from:
machinery
environment
packaging
personnel
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Microbial hazards
Microbial hazards pose the greatest immediate food safety threat to the consumer and enter milk via:
 Unhealthy animal
 People hands
 Milking utensils
 Water
 Production area (GHP)
 Ingredients and additives
 Packaging and packs
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Microbial hazards
 Types of microbiological hazards in milk and dairy products:
Bacteria
Virus
Fungi
Protozoa
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Bacterial hazards
Various bacteria of public health concern found in milk and dairy products include:
M. tuberculosis
Brucella melitancis
Salmonella spp.
Listeria monocytogenes
Campylobacter jejuni
Yersinia enterocolitica
Pathogenic strains of Escherichia coli
Enterotoxigenic strains of Staphylococcus aureus
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Protozoan parasites
 Cryptosporidium parvum
 Entamoeba histolytica
 Giardia lamblia
 Toxoplasma gondii
Viral hazards
 Enteroviruses, including polioviruses and Coxsackie virus, Rotaviruses
 Foot and mouth disease virus
 Hepatitis virus
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Antibiotic drugs
.
Beta-lactams
• penicillins , cephalosporins
Tetracyclines
• Oxytetracycline, tetracycline and
chlortetracyclin
Amino glycosides
• streptomycine, neomycin and
gentamycin
Macrolides
• Erythromycin
Sulfonamides
• Sulfamethazines
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Concerns linked to use of antimicrobials
Potential development of antibiotic-resistant pathogens, which may then complicate human
treatment.
sensitive individuals may exhibit allergic reactions to residues of antibiotics and/or their
metabolites, as mainly seen with B-lactam antibiotics
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Dairy
processing
indigenous
Chemical
hazards
Packaging
Dairy
additives
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Pesticides and insecticides
Contamination of feeds arises in the field or store where treatment with pesticides occurs.
The common pesticides presented below can enter milk and dairy products.
Chlorinated pesticides and related
compounds like DDT
Organophosphates insecticide
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Consumption of these compounds could lead to cancers such as breast cancer.
OC pesticides are fat soluble, so can be found predominantly in high-fat dairy products such as
cream and butter.
Heat treatment of milk and the activity of the starter bacteria in yogurt can decrease its amount.
Most of the developed countries have established maximum residue levels (MRLs) of pesticides
in milk and milk products.
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Hormone residue
Steroid hormones
 The amounts of lipophilic hormones (progestrone and estrogen) depend on the fat content of the milk
and dairy products.
 Food processing does not seem to influence the amount and ratios of the hormones but cheese ripening
does.
 Probably not only propionic acid bacteria but also other fermenting bacteria or clotting enzymes are
responsible for the formation of testosterone during the fermentation process.
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Bovine growth hormone (BGH)
• BGH increases activity and/or longevity of mammary secretary cells, probably via Insulin-like Growth
Factor (IGF)-I produced by the liver and/or the mammary gland.
• Raw milk and pasteurized milk could have levels of IGF-I of 5.6 and 8.2 ng mL-1, respectively.
• Dairy products that contain hormones (such as IGF-I) could increase breast
cancer risk.
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Parasiticide drugs
Albendazole is a widely used benzimidazole anthelmentic. Residues of benzimidazole compounds
such as
 albendazole sulfoxide,
 albendazole sulfone and
 albendazole 2-amino sulfone
can occur in milk and dairy products and it is necessary to observe withdrawal periods for milk
after therapy
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Dioxine & Polychlorinated biphenyls
The known toxic effects of dioxin include
Dermal toxicity,
Immunotoxicity,
Reproductive abnormalities
Endocrine disruption
Carcinogenicity
Dairy products contribute about 1/4 to 1/2 to the dietary intake of total dioxins.
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Heavy metals
 Elements such as chromium and nickel enter from direct contact with stainless steel dairy equipment.
 Heavy metals such as cadmium, lead, mercury, and arsenic are not expected to have any direct contact
with milk .
 They enter milk through the ingestion of contaminated feed and water by milk-producing animals.
Pb
As
Cr
Cd
Cu
Zn
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Heavy metals produce toxic effects by replacing essential metal ions existing in the chelates present in
body
Even in low-level, exposure to inorganic arsenic is related to increased risk of cancer in lung
skin,
bladder
Also, developmental arsenic exposure may lead to increases in pancreatic and hematopoietic cancer
.
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Comparison of heavy metal concentrations in milk samples of different countries
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Mycotoxins
The most important mycotoxins present in dairy products include:
Aflatoxin M1
Fumonisin
Zearalenone
Ochratoxin
Trichotecenes
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Aflatoxins are toxic, carcinogenic, and/or teratogenic to humans and animals.
The International Agency for Research on Cancer (1994) classified AFB1 as a class 1 human
carcinogen and AFM1 as a class 2B possible human carcinogen
AFM1 is relatively stable in raw and processed milk products and is not destroyed by regular heat
treatments including pasteurization.
AFM1 has chronic and acute effects on human health.
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Melamine
 Transfer of melamine from melamine-containing feed to cow’s milk has been reported.
 Furthermore, melamine is a minor metabolite of the pesticide cyromazine and is also used in some
fertilizers.
 The primary target for the toxic action of melamine is the kidneys and the urinary tract.
 Levels of melamine reported in dairy products ranged from 0.09 to 6200 mg/kg
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Processed- produced compounds in dairy products
 Two important factors (such as proteins, fats, carbohydrates, and vitamins) can generate carcinogenic
and mutagenic compounds from dairy ingredients :
1) sever heating
2) exposure to sunlight
 Reactions intensified by high temperature :
Pyrolysis and decomposition
fat oxidation
Maillard reactions
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Fat auto-oxidation and photo-oxidation in high- fat dairy products
Polymerized
compounds
Free radicals
Induction of
Cancer
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Maillard reaction
 The Maillard reaction has considerable consequences on the quality of heated milk and milk products in
terms of
color,
flavor
nutritional value
probable toxic compounds
 Nutritional loss (Lys, Pro, lactose, fat)/Schiff base is digestible but become indigestible after Amadori rearrangement due to
crosslinking of lactose with Pro, so tripsin can not affects it.
 Millard products are act as chelating agents especially for ‘Fe’.
 Some of its products might be toxic and/or mutagenic
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Crosslinking in proteins
β - elimination
Ser
Cys
dehydroalanine
heat
lanthionine
+ cys
+ Lys
lysinoalanine
Cholesterol oxidation products (COPs)
COPs level in milk and dairy products is very small.
Formation of COPs in dairy products can only occur under harsh conditions :
application of high heating temperatures for a long period
long storage at high temperatures,
in the case of foods in the dehydrated state or at low water activities.
COPs have many biological effects such as teratogenic, cytotoxic, mutagenic
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Dairy Additives
Additives such as flavors, colors, sweeteners, antioxidants, and antimicrobial preservatives could possess
toxic side effects when exceeding their respective permitted dose of consumption per day.
Cancer
Brilliant blue FCF, used as a coloring agent, can induce
Malignant tumors
Asthma
Hyperactivity
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Carageenan as a thickening agent
Intestine mucous membrane damage or
Long- term administration cause
ulcerous colonitis,
produce or promote tumor growth
Increase the risk of colorectal cancer
Flavored dairy products that contain sucrose
insulin resistance
pancreatic cancer
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Sweeteners such as saccharin and aspartame have been reported to be carcinogenic agent and induce
bladder cancer.
Chemical additives such as sodium carbonate and sodium bicarbonate added to milk as neutralizers to
preserve it for longer time and to prevent curdling may cause health hazards to the society
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Groups of analytes monitored in milk-PNCRC, 2012
1%
8%
mycotoxins
24%
15%
pestices, organochlorines and PCBs
antiparasitics
antimicrobials
8%
8%
carbamates
organophosphates
pyrethroids
36%
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Programs for hazards prevention and control in dairy industry
HACCP Program
Total Quality Management
Quality Assurance
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Foundation of HACCP -Prerequisite Programs
HACCP
Raw
Materials
Control
Facility
Design
And
Control
Sanitation
Equipment
Design
And
Maintenance
Pest
Control
Employee
Training
Traceability
And
Recall
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An example of possible hazards, control and orientation of yoghurt production
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An example of possible hazards, control and orientation of ice-cream production
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