Food Safety: Testing to Ensure Safety and Build Consumer Confidence Globally

Consumers expect and assume their food will be safe for consumption where ever produced, purchased and enjoyed.  Today’s consumers can be confident in the safety of their food supply due in part to multiple steps taken from the farm to the consumer that ensure food safety.  The food safety measures taken address and minimize residue, pathogen and animal disease risks that could potentially jeopardize the safety of one’s food.

Today, food is sourced locally, regionally, nationally or globally and the need for safety is the same worldwide.  Food Safety Net Services (FSNS) provides the essential step of testing to ensure food safety for their customers and consumers.  This testing helps to build consumer confidence and facilitate food trade.

Testing seems simple, but in reality, it is a core part of a more extensive food safety system that establishes safety, sets standards, monitors products and facilitates trade.  The system includes the private sector and government sector.  It includes the food producer and the food seller.  It includes the input suppliers.  It includes processes, interventions and monitoring.  Each stakeholder has a critical role so that their collective actions result in safe food for all consumers.

Let’s analyze one part of the food safety equation as it relates to veterinary drug residues and see how the system works.  Veterinary drugs are used to keep animals healthy and productive.  They are regulated products, in the U.S. by the Food and Drug Administration Center for Veterinary Medicine (US FDA CVM), or globally by governmental bodies with similar roles.  Further, many veterinary drugs have international standards established via the Codex process.

Establishing safety:  Veterinary drugs need to be determined as safe for use which includes human food safety, animal safety and environmental safety.  Further quality and efficacy criteria must be met prior to their approval for use.  Research studies seek to identify the hazard of and potential exposure to a veterinary drug.  The human food safety is focused on the residue that may be in the food consumed, thus the possible human exposure to the residue.  The exposure is based upon the amount of food consumed and amount of residue in the food consumed.

Two key elements are important for establishing safe levels, the ADI (Acceptable Daily Intake) and the MRLs (Maximum Residue Limits).  The scientific data need to support an ADI and MRLs is derived from human safety information generated from toxicological, microbiological and pharmacological studies.  These tests look at carcinogenicity, genotoxicity, reproduction, teratology and cardiovascular findings.  Chronic and acute aspects are assessed.  Normally, studies are done in animal models such as mice, rats, dogs and monkeys.  Occasionally, data on actual human subjects may be available, especially if the drug came from research for a human pharmaceutical drug.  Through these studies a NOEL (No Observable Effect Level), or a NOAEL (No Observable Adverse Effect Level), is established.

ADI (Acceptable Daily Intake):  The ADI is a measure of a veterinary drug that can be ingested by a person on a daily basis over a lifetime without an appreciable health risk.  The ADI is derived from the NOEL, or NOAEL, with additional safety factors built in that generally range from 10 to 100.  National regulatory authorities, such as the US FDA CVM, or the JECFA (Joint FAO/WHO Expert Committee on Food Additives) used by Codex, all take a conservative approach for establishing the ADI.  For example, often a factor of 10-fold is used to account for individual variability and a factor of 5-fold is used to account for sensitive individuals.  An individual consumer is assumed to weigh 60 kg when calculating exposure risks.  Pending the animal model, or whether human exposure studies exist, scientists always take a conservative approach and incorporate safety factors accordingly for setting an ADI.

MRLs (Maximum Residue Limits):  The MRL is the maximum concentration of a residue resulting from the use of a veterinary drug that is permitted as acceptable in a tissue.  MRLs are established for individual reference tissues including for muscle, fat, liver and kidney (milk, eggs or honey pending the specific species).  These tissues comprise the ‘model diet’ or ‘food basket’ to provide food consumption values for calculating exposure.  When assessing human food safety and setting the MRLs, there is an assumption that a person will eat 300 grams of muscle, 100 grams of liver, 50 grams of fat and 50 grams of kidney daily for a lifetime from animals always administered the drug.

The safety assessment and MRLs consider parent compound as well as metabolite residues.  Radiolabeled studies in target species are conducted to ensure that the total residue profile is understood in establishing human food safety standards.  A marker residue is determined, one with a known relationship to the total residue, and then a marker to total ratio is determined in order to compare the MRL to the ADI.  Further, a target tissue is selected to monitor for the total residues.  When a target tissue is selected, consideration is given that when it is monitored, it should ensure the safety of all tissues.

In the U.S. a ‘tolerance’, rather than an MRL, is established which can be defined as the concentration of the marker residue in the target tissue at the time the total radiolabeled residue in the target tissue has depleted to less than the target tissue safe concentration.  The ‘tolerance’ and the MRLs are correlated but calculated differently.  In the U.S. the ‘tolerance’ is calculated based on consideration that one consumes primarily one tissue, whereas for MRLs the calculation is based on consideration that one consumes all the tissues in the food basket.

The MRLs must be set such that the TMDI (Theoretical Maximum Daily Intake) total from consumption of all tissues is below the ADI.

The use of a veterinary compound often results in a residue of the product (parent compound) or of metabolites of the product (metabolites) in the animal tissues. The concentration of the residue normally is impacted based upon the dose and duration of use.  Typically, the concentration and level of a residue in a tissue depletes over a period of time.

A withdrawal period is established to ensure that the residue level of the parent compound and/or the metabolites, in edible tissue is within the safety tolerance established in the human safety assessment.  The withdrawal period can range from zero to multiple days based upon the depletion of the residue in edible animal tissues.  The point in time of when the residue level is below the established safe tolerance level determines the withdrawal period.

Regulatory authorities in countries establish the product withdrawal period based upon conditions of use within the country.  These conditions of use consider normal food animal production practices and thus help ensure the safe use of the product within a country when products are used according to label directions.  Thus, a withdrawal period, which can vary by country, establishes the period of time at which the residue level is within the established safe tolerance.

Testing and Monitoring:  Analytical methods provide for the screening of and confirmatory findings of compounds to monitor residues in food from animals thus helping ensure a safe food supply.  For compounds used in food animals, when their use could lead to human safety risks, regulatory authorities require the establishment of a method to monitor residues to help ensure their safe use.  Screening methods, often for multiple compounds or classes of compounds, and confirmatory methods, for an individual compound, are used for governmental and industry testing purposes.  The screening and determinative methods need to be validated and very sensitive for both the LoD (Limit of Detection), lowest level of detection, and the LoQ (Limit of Quantitation), lowest level of concentration, that can be reliably measured.

There are various analytical methods that can be utilized to monitor for the residues of a veterinary drug but the capability and limitations of each must be understood when comparing to the MRLs.  Regulatory authorities must determine the appropriate analytical method, target tissue and marker residue for their routine monitoring programs.  Recognizing these various factors, experts must be careful when comparing analytical results and take into consideration adjustment factors that must be utilized to compare various methods and methodologies.  Various methods can each be used to help ensure food safety, however, care needs to be taken when comparing results, as they may or may not be comparable based upon the various factors.

Monitoring results in screening for findings, and then if a finding, conducting a confirmatory test for a specific drug, and the level of the drug to determination if a finding is either within the safe tolerance or violative.  If the finding is within the safe tolerance, the food can be consumed, whereas if the finding is violativ, it is removed from the human food supply.

Food Safety and Trade:  The Codex Alimentarius Commission (CAC or Codex), an international intergovernmental body under the United Nations, was established in 1963 to protect the health of the consumer and facilitate trade.  Codex is the joint food standards program of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO).  It develops food standards, guidelines and related texts such as codes of practice.  The main purposes of Codex are: “… protecting health of the consumers and ensuring fair trade practices in the food trade, and promoting coordination of all food standards work undertaken by international governmental and non-governmental organizations.”

Codex obtains expert scientific advice from JECFA on matters relating to food additives and residues of veterinary drugs in food.  JECFA experts are government or academic scientists from all over the world who serve in their individual capacities as independent experts in the fields of toxicology and residue chemistry, and not as representatives of their governments or employers.  JECFA recommends exposure, an ADI, and residue standards, MRLs, that are based upon a human safety risk assessment and consideration of a food basket consumption approach.  The current tissues considered for the food basket include muscle, fat, liver and kidney.  Further, based upon the scientific assessment, a specific reference tissue is suggested that if monitored should ensure the safe consumption of all tissues.  Codex standards provide an international reference point for countries as they ensure the safety of their meat supply for consumers regarding the use of veterinary drugs used in accordance with good veterinary practices in food animal production.

Codex and JECFA developed a global market-based approach to determine food basket consumption factors that are considered in food drug-residue risk assessments.  Regarding other tissues — beyond those of muscle, fat, liver, kidney, milk, egg and honey that comprise the current food basket — scientific assessments cannot be completed on such other tissues currently, since there is no information available on international, regional or national dietary consumption of such tissues for conducting an evaluation.  One needs a tissue residue profile and a tissue consumption factor to establish an MRL for a given tissue.

Codex standards serve as international food safety reference standards. Countries may adopt the Codex standard based upon the internationally recognized human food safety assessments. However, under the World Trade Organization (WTO) Agreement on the Application of Sanitary and Phytosanitary Measures (SPS Agreement), countries have the sovereign right to establish their own standards which result in a higher level of protection provided they have a scientific basis upon which the standard is established in providing for protection of their consumers.

Safe food is an expectation of consumers globally.  Establishing safety standards and monitoring to ensure compliance provides for safe food.  Food Safety Net Services plays an essential role through testing to ensure food safety and food trade.

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* Sources include information and knowledge gathered from the U.S. Food and Drug Administration Center for Veterinary Medicine; the Codex Alimentarius Commission and websites of Codex, FAO and WHO; the International Poultry Council; and Elanco.

** Dennis L. Erpelding is a consultant and speaker focused on global policy and strategic counsel regarding corporate affairs, trade access, food safety and international standards.  He founded Global Farm View, LLC to provide strategic counsel to food chain stakeholders globally taking a view from the farm to the consumer; thereby leveraging his global experiences and networks for the betterment of food animal production and food consumers.

Erpelding retired from Elanco, a division of Eli Lilly and Company, December 31, 2017 after over 28 years traveling globally engaging with governments and all food chain stakeholders advancing policy and trade access that supported innovation in the animal health sector.  He has broad experience formulating strategy and policies in the legislative, regulatory, food chain and scientific areas; including successfully shaping laws, regulations and policies in the Americas, Asia and Europe that supported food animal production and trade.

Erpelding has served in numerous volunteer leadership roles including as Chairman of the Food and Agriculture Export Alliance, on the Operating Committee of the U.S. Dairy Export Council, as Chairman of the U.S. Meat Export Federation and as President of the National Agri-Marketing Association.  He represented Elanco with the International Poultry Council and the International Meat Secretariat.

A native of Whittemore, Iowa, U.S.A., Mr. Erpelding was raised on a diversified livestock and crop farm.  He received a Bachelor of Science degree in Dairy Science from Iowa State University in 1981 and in 1989 he earned a Master of Business Administration degree from The Ohio State University.  He currently resides in Thailand and the United States of America.  Erpelding can be contacted via email at

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