For one thing, Benner tells The Salt, Latinos tend to apply for certain types of jobs, like dishwasher, line cook and table busser. Likewise, such so-called "back-of-house" positions are not generally targeted by Caucasian applicants, who more often seek higher-paying bartender and waiter positions.
"We call this the self-selection bias," says Benner, whose research involved interviewing owners and managers at 12 California restaurants, half of which were high-end establishments, and closely analyzing national industry data. "People may just not see themselves as working in a certain area."
Sometimes, he says, customers may drive the bias against immigrants filling front-of-house positions.
"We've heard of a lot of stories where the customer actually asked for a different server, because they had a hard time understanding the accent of whoever the server is," he says.
This is not the first time a close look at the restaurant industry has revealed striking inequity in the labor force. The organization Restaurant Opportunities Centers United went undercover in 2011 and 2012 and found that upscale restaurants were racially discriminating in their hiring process.
The national group sent pairs of equally qualified individuals — one person white, the other not — to apply for jobs at white tablecloth-type restaurants in Chicago, Detroit and New Orleans. The group repeated this method, called "matched pair testing," 273 times.
"Testers of color [in Chicago] were only 53 percent as likely as white testers to get a job offer, and were less likely than white testers to receive a job interview in the first place," according to the resulting report, published in 2014. Applicants of color fared better in the other cities, but were still far less likely than their white counterparts to get the job.
That study was led by Saru Jayaraman, co-director of Restaurant Opportunities Centers United and the director of the Food Labor Research Institute at UC Berkeley. She tells The Salt that about 20 percent of restaurant jobs pay exceptionally well. In the San Francisco Bay Area, for example, servers and bartenders can take home as much as $180,000 per year, she says – if they're working in upper-end establishments, the kind with $125 a person tasting menus, for example.
"But these jobs are held almost exclusively by white people, and in particular, white men," says Jayaraman, who also collaborated with Benner on the more recent research.
Latinos, she says, tend to spend their restaurant careers in back-of-house jobs, earning somewhere closer to $30,000 per year – with few paths for promotion or pay raises. Jayaraman says she has interviewed Latino table bussers who reported having helped train newly hired white employees who were easing into positions waiting tables.
"Then, within weeks or months, the people they're training are earning five times what that busser is making," she says.
African-Americans seem to have a particularly tough plight in the restaurant industry, mostly working in down-market restaurants where wages and tips are minimal.
"For African-American workers, it's almost 100-percent exclusion from [fine dining restaurants] altogether," Jayaraman says. "They work almost exclusively at fast-food restaurants or very casual restaurants like Red Lobster."
Most of the big bucks in the restaurant industry come from tipping — a practice that is increasingly coming under scrutiny. Prominent New York restaurateur Danny Meyer recently banished tipping in his eateries as a step toward equalizing the skewed pay scale. In an interview with NPR, he noted that waiters' take-home pay at fine restaurants has skyrocketed thanks to tips, but the pay of workers at the back of the house hasn't kept pace. And women workers who rely on tips may feel obliged to tolerate sexual harassment from customers, Jayaraman argued in a recent op-ed for The New York Times.
The National Restaurant Association thinks little of the new "Ending Jim Crow" study.
"The restaurant industry is one of the most diverse industries in America, with zero barriers to entry and endless pathways to success," says Katie Niebaum, the association's vice president of communications, who corresponded with The Salt via email.
Niebaum, citing U.S. Census Bureau numbers, says restaurant ownership among minorities and women "outpaced growth in the overall industry during the last 10 years on record."
"In addition, we proudly employ more women and minority managers than any other industry," she says. "Two in five restaurant managers are women; overall, one in three come from a minority background."
The researchers agree that the restaurant industry is more racially diverse today in America than in the past.
But that, Jayaraman warns, should not necessarily win the industry any brownie points.
"It just makes the segregation more and more pernicious, because we see greater concentrations of people of color in lower-level positions," Jayaraman says.