qualitative and quantitative analyses of antibiotics, heavy metals, mycotoxins, and pesticides...

04/12/2023 07:38 AM

College of Veterinary and Animal Sciences , Jhang (UVAS, Lahore)

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INTERIM REPORT

Qualitative and Quantitative Analyses of Antibiotics, Heavy Metals, Mycotoxins, and Pesticides Residues in Milk, Eggs and Meat Meant for Human Consumption

Dr. Muhammad Younus-Principal Investigator Dr. Tariq Abbas -Co-Principal Investigator

04/12/2023 07:38 AMCollege of Veterinary and Animal Sciences , Jhang (UVAS, Lahore)

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Outline

Introduction/ Background Health effects of chemical contaminants

in milk Problem statement Review of literature at a glance Methodology AND hypotheses Progress to date and future plans


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Introduction/Background

Pakistan is the fourth largest milk producing country located in a milk deficient region.

It has rapidly increasing demand and competition in international market.

Milk consumers in Pakistan are often faced with low-quality, adulterated milk.

Lack of hygiene, adulteration with various agents, and absence of cold chains are primary contributors to this low quality.


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Residues in milk may come through : i) feed and water , ii) drugs , iii) post harvest contamination & adulteration


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Introduction/Background

Malicious chemicals in various farm inputs (e.g. concentrates), agriculture, drinking water, environmental pollution, and use of veterinary drugs lead to excretion of residues in milk.

As such there are no data on the content of these chemicals in milk and a system for their effective surveillance.


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Health effects of residues in milk- Antibiotics

Antibiotics are widely used in dairy sector, both for treatment and prophylactic purposes.

Antibiotics residues in milk can be potential hazard and may cause serious illness to people, such as hypersensitivity and allergic reactions.

They may also increase the resistance to pathogenic bacteria

In addition, antibiotic residues in milk cause inhibition of bacterial starter cultures used in dairy production (losses !) .


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Drugs prohibited for extra-label use in animals being prudently used without observing codal formalities


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Health effects of residues in milk- Pesticides

Multiple studies indicate a wide range of pesticide-related clinical and subclinical effects, including significant positive associations between pesticide exposure and solid tumors, hematological cancers, and genotoxic effects.

In addition, pesticides were found to impact on mental and emotional functioning, the nervous system – causing Parkinson’s disease and other neurological diseases, and the reproductive system diseases – causing birth defects, fertility, fetal death, and intrauterine growth retardation.


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Health effects of residues in milk-Mycotoxins

Aflatoxin B1 (AFB1) produced by moulds in the contaminated cattle feed get transformed to 4-hydroxylated metabolite known as “milk toxin”, i.e., aflatoxin M1 (AFM1) in mammals (B1 to M1 conversion in stomach of cow).

The fungal toxin is resistant to high temperature treatments including pasteurization and sterilization.

The presence of AFM (1) in milk, pose a major risk for humans especially kids as it can have immunosuppressive, mutagenic, teratogenic and carcinogenic effects

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Mouldy feed- a source of mycotoxins for dairy animals and their milk


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Health effects of residues in milk- Heavy metals

A variety of exposure routes allow toxic heavy metals predominantly lead and cadmium to enter the food chain of dairy farm animals, the commonest being come through :

The contaminated animal feed and water, Atmospheric deposition , Land application of inorganic fertilizers, biosolids,

agrochemicals, Urban , industrial effluents and animal manures

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Urban and industrial wastes from Jhang city being used in Agriculture and falling into river


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Problem statement

“There are few studies on contamination level of various chemical residues in unprocessed, non-branded liquid milk available at conventional milk shops in various cities of the country such as Jhang”.

The objective of this project is to quantify the residues of selected mycotoxin, heavy metals, pesticides and antibiotics in milk being sold on the street shops in Jhang city.

04/12/2023 07:38 AM

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Unprocessed , unbranded liquid milk being sold on traditional street shops in Jhang city


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Review of exiting studies

Given the importance of chemical residues in milk and dairy products, different countries have conducted studies related to antibiotics, pesticides, Aflatoxin M1 and heavy metals. The review of such studies is given as a separate chapter in the report.

“In short ; results of the studies provided a base-line information for veterinary authorities, drug administration and quality control, other concerned organizations and professionals to take measures in controlling and preventing of occurrence of drug residues”.


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Endnote library !


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Methodology : Description of the study area

Jhang (Urdu: جهنگ, Punjabi: جھنگ), is the capital city of District Jhang which is located at the gateway of central Punjab - the milk belt of Pakistan. It is situated at place where two rivers Jhelum and Chenab join each other (Head Trimu)

It is a neglected area, rich in livestock and focus for improvement in dairies particularly Sahiwal breed of cattle.

The city has been purposively selected because its dairy production and marketing is representative of the whole country.

In year 2006, College of Veterinary and Animal Sciences, Jhang was established. The college intends to make the Jhang a model District and sentinel for livestock related researchable issues.


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Methodology : Selection of the chemical contaminants

After review of literature, field visits and informal meetings with the dairy experts , a list of chemical contaminants was prepared for inclusion in the survey.

The chemicals were selected on the basis of following two criteria:

1. Possibility level in milk through farm inputs (e.g. concentrates etc) , agriculture, drinking water, medication, environmental contamination and/adulteration, and

2. Public health effects


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Methodology : Selection of the chemical contaminants

Category Chemical NameHeavy metal Lead

Chromium Copper Cadmium

Mycotoxins Aflatoxin M1Antibiotics Enrofloxacin

Penicillin GStreptomycinGentamycinOxytetracycline

Chloramphenicol

Pesticides AcephateChlorpyrifos CypermethrinLambda Cyhalothrin


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Hypotheses maintained and to be tested

1. The mean concentration of residues of any selected chemical contaminant in unprocessed, non-branded liquid milk available at conventional retail shops of Jhang city is more than maximum residue level(MRL)

2. For any selected chemical contaminant, there is an association between proportion of positive samples and seasons [positive sample means samples with concentration of more than MRL ]


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Methodology : Sampling strategy

From the street-level map of the Jhang city, 100 streets were randomly selected and geo -referenced in Quantum GIS version 1.8.0 Lisboa(Roads>Streets>shops)

In each street, every second shop (right/left) was selected through systematic random walk from entrance to the street .


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100 streets randomly selected followed by systematic random walk sampling


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Methodology:Sampling

From each selected shop, 250 ml of unprocessed liquid milk was purchased, out of which 25 ml was sampled (in duplicate) in clean sterilized screw capped glass tubes.

The sampling was done from November to December, 2012.

The sampling will be repeated during mid summer and moonson of 2013

The sample size was decided from already published journal articles on same topic and available resources.

The sample size will be re-assessed later based on initial findings


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Methodology : Data analyses

The data shall be analyzed in SPSS version 21. Beside descriptive analyses, one sample t-test will be used for hypothesis testing with maximum residue level (MRL) as test value.

The proportion of samples with more than MRLs will be compared across seasons using Chi square test.


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Progress to date

Review of literature : completed (Endnote Library given in methodology)

Selection of chemical of contaminants : Decided (Table given in methodology)

Devising a strategy to sample shops through a probability sampling : Multi stage cluster sampling through GIS (Google Earth file & shapefile created)

First round of sampling : completed and being analyzed


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Future plans

The sampling will be repeated during summer and moonson to assess seasonal trends if any.

The same samples shall further be analyzed to quantify antibiotics, and pesticides mentioned in the table.

The results will be discussed with dairy association to plan recommendations to control the problem using measures feasible in local settings.


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Thanks

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