In its ongoing effort to boost its sales and financial performance, McDonald's (NYSE:MCD) announced two major changes to its hamburger preparation earlier this week.

The company plans to toast its buns for five seconds longer, which will make the bread 15 degrees warmer, and it will also sear its burger patties to make them juicier, though it did not provide any further detail on that technique.  

The decisions represent the most specific information McDonald's has provided on how it plans to improves its food quality. New CEO Steve Easterbrook has said many times that he wants McDonald's to be a "modern, progressive burger company." More recently, he said his goal was to deliver "hotter, tastier food" to the customer. 

Easterbrook is to be commended for his efforts to boost McDonald's food quality, including the recent introduction of sirloin third-pound burgers and a promise to eliminate human antibiotics from its chicken. However, the bun presents a particular problem that's emblematic of McDonald's greater challenges. 

The bread conundrum
This is not the first time McDonald's has toyed with its bun preparation. In the 1990s, in an effort to boost speed of service, the chain stopped toasting buns altogether. Though speed improved as a result of the decision, quality declined and customer complaints poured in. In 1997, McDonald's chose to rectify the situation by asking franchisees to install toasting equipment at a cost of $7,000 a pop and promised customers that every burger would be made to order.

But to toast or not to toast isn't the only question facing operators like McDonald's. The bun -- and bread in general -- presents a unique set of challenges for fast-food chains. Without loads of preservatives, bread tends to have a shorter shelf life than anything else commonly found in a fast-food kitchen, and it doesn't take so well to freezing the way other items do.

The bun is also arguably the most overlooked part of the burger, as it constitutes one of just two essential ingredients for a hamburger, the other being the meat. Rivals like Wendy's have tried to differentiate themselves recently by offering alternatives such as pretzel rolls, while McDonald's is testing alternatives like brioche and foccaccia in foreign markets.  

In the race to become more "natural," other chains have also been updating their bread products, some with more success than others. Panera Bread said earlier this month that it would remove as many as 150 ingredients from its menu by 2016, many of them from its bakery products, in response to popular demand.

Chipotle Mexican Grill, which prides itself on delivering "Food with Integrity," does not use preservatives in any of its foods -- except for tortillas. Even as Chipotle has reduced the use of preservatives in its tortillas, it's proven difficult to remove the additives entirely. 

More than just flour and water
A look at the ingredients list for McDonald's standard bun reveals that high fructose corn syrup is a major ingredient as well as several dough conditioners and the preservative calcium propionate. 

In its "Our Food. Your Questions" campaign, McDonald's admitted that its buns contain the same ingredient, azodicarbonamide, that is often found in yoga mats, but said it was completely safe and is FDA-approved for use in food. 

By comparison, better-burger standout Five Guys avoids corn syrup, preservatives, and conditioners in its buns, and the buns are the only proprietary product in its kitchen, a sign of the chain's emphasis on fresh bread. Shake Shack recently stepped up its bread game by removing GMOs from its buns.  

Even Subway, the only fast-food chain with more domestic locations than McDonald's, last year said it would eliminate the "yoga mat" chemical in response to protests. The Golden Arches, then, seems to be lagging behind the competition in more ways than one.  

For McDonald's, giving greater attention to its bun is a good first step, but the toastiness isn't the only area that could use an update. Revisiting the ingredients list and the recipe would likely do more to reestablish consumers' trust, improve quality, and boost sales.