By Lewis Perdue
Reducing environmental chemicals is vital in a properly designed dietary intervention study. That makes it more likely that blood markerssuch as inflammation will be measurably different between the before (normal food and environment) and after (reduced contamination) legs of the study.
Because of that, a causal and replicable experiment requires extreme laboratory-precise actions for test subject environment as well as food acquisition and preparation.
For more on this issue, please see: Reducing Non-Food Exposures.
Materials: A look at the test kitchen
Requirement: As with all appropriate bench science work, preparation surfaces should be non-reactive, non-porous, resistant to chemicals, heat, and easy to clean. Stone or ceramic tiles can accumulate contaminants in grout. Sealants will contain polymers. Polymer-based surfaces cannot be used.
This ad-free article is made possible by the financial support of the
Center for Research on Environmental Chemicals in Humans: a 501(c)(3) non-profit.
Please consider making a tax-deductible donation for continued biomedical research.
Menu planning
Dietary interventions also require that preparation surfaces must be efficient to maintain hygiene in the event that food makes incidental contact.
Stainless steel offers all of those characteristics which is why professional and health-department approved kitchens are almost totally stainless steel.
Environment: Ventilation & PM2.5
Constant ventilation of HEPA-filtered air is vital to prevent contamination of food with polymer-based particles which can confound results. Air should be constantly monitored throughout the trial and records kept.
The type and age of the HVAC system should be noted as well as the type of filter used and the ducting materials (metal versus plastic).
Immediately after dusting, the HVAC filter should be changed and the system fan run continuously for four hours to collect as much dust as possible which has been stirred up from cleaning. A fresh filter should then be installed. Filters should be the highest MERV number possible without stressing the HVAC system.
HEPA-class air purifier use should report the make, model, capacity, and whether it is portable or installed with the HVAC system. If portable, the location should be noted along with the distance from the HVAC air return.
Controlling PM 2.5 Air Pollution
Our previous study noted that that BPA increases inflammation. Because of that, we chose a standard hospital blood test for inflammation — hsCRP — to see if reducing BPA levels would reduce inflammation.However, we needed to control for the confounding effects that a common air pollutant could cause. That pollutant — breathing particles of PM 2.5 (such as those filtered by N95 masks) also raises levels of inflammation in humans. So, to avoid having the effects of bad air from tainting our test results, the test kitchen, and the main study scientist doubling as the lab rat (and living in the home in which the test kitchen was located) needed to be insulated full-time from PM 2.5.As experiences from the Covid pandemic illustrated, wearing a mask was uncomfortable, and impractical for 24 hours per day use.In addition to daily damp mopping of floors, the study involved installing MERV 8 filters in the HVAC, and using six Germ Guardian units, two for the 200-square-foor kitchen and four more for the rest of the 1,500 square-foot house.The Germ Guardian units filtered large particles as well as PM 2.5 and ran 24-hours per day. The charcoal filter also removed smells and other organic compounds that could affect inflammation levels.
Monitoring PM 2.5 Air pollution
PurpleAir is an accurate and cost-effective solution for monitoring PM 2.5.
Other than the cost of the sensor ($199), monitoring is free and historical data can be downloaded and saved.
Polymer-based materials are universally found in professional and institutional kitchens given to their durability and ease of cleaning. However, friction against the floor caused by shoes and rolling carts inevitably creates ultra-fine particles many of which qualify as PM2.5 which — regardless of chemical composition — cause inflammation when inhaled. Significantly, many of the polymers from which flooring is made (such as polyvinyl chloride) have known health effects and can contaminate food destined for test subjects.
For this and standard hygiene reasons, floors should be wet-mopped with at the end of every food preparation day. The cleaner for this task and food preparation surfaces should be hypochlorite-based and free of surfactants such as ethoxylates that have been shown to cause measurable health effects.
Spills and other unanticipated incidents should be cleaned with water — minus cleaning agents — when possible. Exceptions should be noted in the list of materials.
Cleaning Protocol: Preparation Surfaces
The same cleaning agents and protocols should be employed. No paper towels.
Towels: Sourcing and Washing
Only 100% cotton towels should be used. The source should be noted in the list of materials. Before first use, study towels should be washed and dried twice to remove any potential contaminants.
Towel, apron and other cloth washing
A new washer and dryer should be a purchased for a dietary intervention study because difficult-to-remove fabric softener and detergent residues can build up on the internal surfaces up from phthalates and other chemicals contained in detergents and fabric softeners. These can be basic, no-frills consumer-level, budget units. Note the brand/model of both.
Dishwashing
Replacing an institutional dishwasher is impractical and economically not necessary.
Before first use, dishwasher (note brand/model/age noted in equipment) should be run twice with an empty load using the detergent selected for the study. This will minimize deposits of undesirable chemicals.
The dishwasher should use the most vigorous setting (pots/pans), hottest final rinse. Do not use a heated dry cycle which may “bake on” organic contaminants. Instead, remove items immediately upon cycle finish when they are still wet. Then rinse all items under a running stream of carbon-filtered water and place in a stainless-steel dish rack to dry.
Age of clothes washers, dryers, and dishwashers is important
The age of clothes washers, dryers, and dishwashers with plastic components should be noted because polymer components — including seals — will leach more chemicals and additives as they age because many of the additives compounds are not covalently bound.
Leave a Reply