There Are Pandas, and Then There Are Pandas.
And this isn't either of them! The Pandas we're talking about here, are watches, not bears. And what got me thinking about them (again) was a link posted this morning by @cm.rook who pointed a few of us to the very attractive (and not terribly priced) Yema "Rallygraph" Panda which, in it's most traditional arrangement, looks like the one on the left, but can also be had in the version on the right: The model on the left is a true Panda, while the model on the right is called a reverse Panda. The reason for that distinction is clear--Panda bears, only come in the first arrangement. Now at this point, everyone should be thinking about the most well-know Panda, The Rolex Panda, which is actually a Daytona, and among Rolex Daytonas, the most famous of which is the Paul Newman Daytona, which was famous first, because it was Paul's, and second because it sold at auction for $17.8 million (US Dollars). The story of that auction is well-known so I'll only...
Nov 8, 2019
http://faculty.vetmed.ucdavis.edu/faculty/docliver/Research/cuttingboard.htm
"We soon found that disease bacteria such as these were not recoverable from wooden surfaces in a short time after they were applied, unless very large numbers were used. New plastic surfaces allowed the bacteria to persist, but were easily cleaned and disinfected. However, wooden boards that had been used and had many knife cuts acted almost the same as new wood, whereas plastic surfaces that were knife-scarred were impossible to clean and disinfect manually, especially when food residues such as chicken fat were present.... we regard it as the best epidemiological evidence available to date that wooden cutting boards are not a hazard to human health, but plastic cutting boards may be."
These are authoritative scientific studies relevant to your product:
CDC. "Salmonella and Food." National Center for Emerging and Zoonotic Infectious Diseases; Centers for Disease Control and Prevention, 2017. https://www.cdc.gov/features/salmonella-food/index.html
Cliver, D. "Cutting boards in Salmonella cross-contamination." Journal Of AOAC International, 2006, 89(2), 538-542.
Heinitz, Ruble, Wagner & Tatini. "Incidence of Salmonella in fish and seafood." Journal of Food Protection - International Association for Food Protection. 2000 May; 63(5): 579–592.
Soares, V. M., Pereira, J. G., Viana, C., Izidoro, T. B., Bersot, L. S., & Pinto, J. N. "Transfer of Salmonella Enteritidis to four types of surfaces after cleaning procedures and cross-contamination to tomatoes." Food Microbiology, 2012, 30(2), 453-456. doi:10.1016/j.fm.2011.12.028 Venkatasubbu, Baskar, Anusuya, Seshan & Chelliah. "Toxicity mechanism of titanium dioxide and zinc oxide nanoparticles against food pathogens." Colloids Surf B Biointerfaces. 2016 Dec 1;148:600-606. doi: 10.1016/j.colsurfb.2016.09.042. Epub 2016 Sep 28. I would argue that they contain mountains of research and discussion that you – as the manufacturer of these chopsticks – are ethically obligated to not only understand, but understand very, very well. Below are some snippets from a study by Soares & colleagues and Cliver that addresses two important aspects of your product: the porous material and the ineffectiveness of “hand washing” a material - which we can agree is relevant to your product that must be “washed by hand.”
“In procedure 2, the recovery of S. Enteritidis NAL from wooden cutting boards was significantly greater (p < 0.01) than from the other materials (Table 1). Abrishami et al. (1994) also reported that after cleaning with cold water, more bacteria remained adhered to wood than to plastic and that rinsing alone was not able to remove bacteria from wood” (Soares et al., 2012). “After procedure 3, small amounts of the microorganism were recovered from wood and were undetectable on triclosan-treated plastic, glass, stainless steel, and tomatoes” (Soares et al., 2012). “It may be concluded that cutting boards are critical factors when handling raw foods contaminated with pathogenic microorganisms. Among the surfaces analyzed, wood was considered to be the most difficult to clean and stainless steel was the easiest. Cleaning with cold water and dish soap followed by vigorous scrubbing and rinsing, practices commonly followed in household kitchens to clean cutting boards, may reduce but not eliminate the risk of exposure to the pathogen" (Soares et al., 2012). The study by Cliver (2006), which is conveniently cited at the bottom of the scientifically inadequate source that you linked to, contains the following in its abstract:
“Wood is intrinsically porous, which allows food juices and bacteria to enter the body of the wood unless a highly hydrophobic residue covers the surface. The moisture is drawn in by capillary action until there is no more free fluid on the surface, at which point immigration ceases. Bacteria in the wood pores are not killed instantly, but neither do they return to the surface. Destructive sampling reveals infectious bacteria for hours, but resurrection of these bacteria via knife edges has not been demonstrated. Small plastic cutting boards can be cleaned in a dishwasher (as can some specially treated wooden boards), but the dishwasher may distribute the bacteria onto other food-contact surfaces. Most small wooden boards (i.e., those with no metal joiners in them) can be sterilized in a microwave oven, but this should be unnecessary if accumulation of food residues is prevented. However, 2 epidemiological studies seem to show that cutting board cleaning habits have little influence on the incidence of sporadic salmonellosis. In addition to these findings is the fact that chopsticks are frequently used to pick up raw fish, so there is significant concern for a number of salmonella-related issues (CDC; Heinitz et al., 2000). " The research goes on and on, and don't see that it ends with the confirmation that it's a good idea to pick up raw meats with porous, unfinished wood. Indeed, I'm confident that you, @KentWang, would outright refuse to soak your chopsticks in pathogens, hand wash them (i.e., fail to sterilize them), and then eat with them. Folks - if you want to prevent foodborne illness and impress your guests, food-grade titanium chopsticks are the much better option due to titanium's (dioxide compound) resistance to pathogens and the fact that you can sanitize them with exposure to very high temperatures (Venkatasubbu et al., 2016) - something you can't do to raw wood. And don't forget about its natural beauty and strength; who doesn't think “wow” when they hold titanium? Finally, citing a study published in Scientific Reports, NPR just did a story recently revealing that the dirtiest place in your home is the kitchen sponge (Doucleff). Yeah, the same sponge that you expose high heat and cleaners to. So let's not be so naive as to think that porous wood chopsticks rinsed in not-hot-enough-to-burn-you water are somehow cleaner. Be smart, people.
also, you shouldn’t use hard metals for things you put in your mouth, as they have a higher hardness than your bones (teeth). This can damage your teeth over time. The only metal I know of that is softer than bone is gold.
Also, just realized your comment is like 2 months old... oh well.
for instance this line that you emphasized: Bacteria in the wood pores are not killed instantly, but neither do they return to the surface.
It's important to note that while there might be live bacteria inside the cutting board, unless they're on a surface that touches your food, they're a non-issue.
If you're really worried, there's always the microwave.
The same could be said about properly washed and maintained wooden cutting boards. You should always hand-wash them to keep the oils in the wood and you should oil them at least once a month to replenish those oils. I'm not sure if there is any reason to treat your chopsticks with oil, but it probably wouldn't hurt anything to do so if you are worried about food-born pathogens.