Do Kitchen Items Shed Antimicrobial Nanoparticles After Use?

November 19, 2018
Because of their antimicrobial and antifungal properties, silver nanoparticles measuring between one and 100 nanometers (billionth of a meter) in size, are being incorporated outside the United States into a variety of kitchen products known as food contact materials (FCMs). Among the nanosilver-infused FCMs now on the market overseas are spatulas, baby mugs, storage containers and cutting boards. However, the use of these items raises concerns that the nanoparticles in them will migrate into foods and the environment, and in turn, whether this poses risks to human health. 
 
To address these issues, government bodies around the world have published guidance documents, set policies and considered regulations. These have been largely based on research that examined nanosilver release from new, unused consumer products or laboratory surrogates, but not actual FCMs during and after use. In a new paper, scientists from the U.S. Food and Drug Administration (FDA), the National Institute of Standards and Technology (NIST) and the U.S. Consumer Product Safety Commission (CPSC) describe how they simulated knife motion, washing and scratching on nanosilver-containing cutting boards to see if consumer use practices affect nanoparticle release.
 
Using a test method developed at NIST, five different use scenarios—each simulating a different type and level of wear commonly seen with human use—were conducted by moving three abrasive surfaces back and forth across samples of nanosilver-enabled cutting board material. 
 
The researchers hope their test method will help regulatory bodies identify if any safety or health risks exist from silver nanoparticles in food contact materials, and if so, find ways to deal with them appropriately before they are approved for sale in the United States.
 
“A custom-designed razor blade replicated knife cuts, a piece of scrubbing pad mimicked normal dishwashing conditions and a tungsten carbide burr imitated scratching by metal utensils,” said NIST physical scientist Keana C.K. Scott, one of the authors on the paper published in the journal Food Additives and Contaminants: Part A. “The washing and scratching scenarios were done at one or two levels of abrasion; for example, 500 and 5,000 cycles for the scratching simulation.”
 
After the abrasion runs, the NIST researchers used sticky tape to see if loose silver nanoparticles were present and could be removed from the worn cutting-board samples. Scanning electron microscopy (SEM) at NIST and inductively coupled plasma mass spectrometry (an incredibly sensitive method for detecting metal ions) at the FDA showed that bits of cutting board polymer were released by abrasion and that some of these contained embedded silver. However, free silver nanoparticles were not found on the SEM-examined tape.
 
FDA scientists also determined how much, if any, silver ions and intact silver nanoparticles would migrate away from cutting boards when exposed to water and acetic acid. They found that the concentrations of ionic and particulate silver found in both solutions were very low. In fact, there was no discernable difference in the silver migration observed from the new and unused nanosilver-enabled cutting boards compared with the ones that were cut, washed or scratched.
 
Based on their findings, the NIST and FDA researchers suggested that future studies should examine whether a combination of use scenarios would increase the amount of silver ions or nanoparticles released. For example, they said, perhaps washing the cutting board after scratching would have a different impact.
 
“Now that we’ve shown that the migration evaluation method works, it can be used to help answer this and other questions about what happens when people use FCMs with nanoparticles,” said NIST research chemist David Goodwin, another author on the paper. “In turn, those findings should be valuable for the bodies that must determine any health or safety risks.”
 
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Florida Window and Door Manufacturer Cited after Employee Suffers Partial Finger Amputation
 
OSHA has cited PGT Industries Inc. – operating as CGI Windows and Doors Inc. in Hialeah, Florida – for machine guarding hazards after an employee suffered a partial finger amputation while working on an unguarded punch press. The window and door manufacturer faces $398,545 in penalties, including the maximum amount allowed by law for the violations that can cause life-altering injury.
 
OSHA cited the company for a lack of machine guarding on several pieces of equipment, for failing to implement a program to inspect mechanical power presses and correct unsafe conditions, and failing to develop specific procedures to verify the control of hazardous energy. In addition, OSHA issued citations for the company’s failure to ensure employees wore hearing protection, to correct electrical hazards, anchor a drill press, and to record injuries and illnesses within seven calendar days.
 
“This employer knowingly disregarded machine guarding requirements intended to protect employees from caught-in and amputation hazards,” said OSHA Fort Lauderdale Area Office Director Condell Eastmond.
 
The company has 15 business days from receipt of the citations and proposed penalties to comply, request an informal conference with OSHA’s area director, or contest the findings before the independent Occupational Safety and Health Review Commission.
 
Nebraska Staffing Agency Cited Following Heat-Related Fatality
 
OSHA has cited Rivera Agri Inc. – a provider of temporary agricultural labor – for failing to protect employees working in excessive heat after a farmworker succumbed to apparent heat-related symptoms while working in a cornfield near Grand Island, Nebraska.
 
The heat index reached 100 degrees on two days in July 2018. OSHA inspectors determined that the company failed to implement and train employees on a heat injury and illness prevention program. OSHA cited the company for a serious violation of the General Duty Clause, and proposed penalties totaling $11,641.
 
“This tragedy underscores the need for employers with workers exposed to high temperatures to take simple, well-known precautions – such as ensuring workers have access to water, rest, and shade – to keep workers safe in extreme heat,” said OSHA Omaha Area Office Director Jeff Funke.
 
OSHA's Occupational Exposure to Heat webpage explains what employers can do to keep workers safe and what workers need to know - including factors for heat illness, adapting to working in indoor and outdoor heat, protecting workers, recognizing symptoms, and first aid training.
 
Cites Alabama Manufacturer Fined for Exposing Employees to Amputation, Fall, and Other Hazards at Four Facilities
 
OSHA has cited Sabel Steel Service Inc. – based in Montgomery, Alabama – for exposing employees to amputation, fall, and other hazards at four of the company’s facilities. The manufacturer faces $320,261 in penalties.
 
OSHA conducted separate inspections at the company’s facilities in Montgomery, Dothan, and Theodore, Alabama; and in Newnan, Georgia. OSHA cited the company for exposing employees to amputations hazards; failing to use safety procedures to control the release of hazardous energy during machine maintenance or servicing; provide fall protection; conduct medical evaluations to determine an employee’s ability to use a respirator; and improperly storing oxygen, propane and acetylene cylinders; and electrical and fire hazards. The inspections are part of OSHA’s National Emphasis Program on Amputations.
 
“Employers are required to conduct regular assessments of their workplaces to identify safety hazards that can put employees at risk for serious or fatal injuries,” said OSHA Mobile Area Office Director Joseph Roesler.
 
EU Deal on Protecting workers from Exposure to Diesel Exhaust
 
A deal on new EU rules to better protect workers from exposure to carcinogenic and mutagenic substances was struck by Employment Committee MEPs and the Council.
12 million workers in the EU potentially exposed to diesel engine exhaust emissions (DEEE) will now be better protected, as diesel fumes and their corresponding exposure limit value were added to the final deal.
 
The second revision of the 2004 directive intends to further lower the risk for workers of getting cancer, which is the primary cause of work-related deaths in the EU.
 
The negotiators agreed on the European Commission proposal to set the exposure limit values (maximum amount of substance allowed in workplace air) and/or skin notations (possibility of significantly absorbing substance through the skin) for five additional carcinogens: trichloroethylene, 4,4-methylenedianiline, epichlorohydrine, ethylene dibromide and ethylene dichloride.
 
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