Tesco could hardly complain about a poor turnout as it made its grand opening in the United States yesterday – the aisles and car park of its inaugural store, in the Los Angeles neighbourhood of Glassell Park, were as jammed as the surrounding freeways in the morning rush hour.

But the company's plans for a joyous celebration of spicy blue tortilla crackers and organic crunchy peanut butter were also marred by the – metaphorical – stench of a few rotten eggs.

Shoppers who lined up for more than an hour to be among the first to patronise Tesco's new mid-sized Fresh & Easy stores – 200 of which will spring up across California and the American Southwest over the next few months – were greeted by a giant banner on Eagle Rock Boulevard reading: "Shame on Fresh & Easy!"

On their way in they were handed leaflets by a group called the Alliance for Healthy and Responsible Grocery Stores – a coalition of community activists, church leaders and union organisers who do not trust Tesco's promises of a living wage for its workers, of plentiful health and other benefits, of environmental sensitivity and a commitment to serve poor neighbourhoods with little or no access to fresh, high quality food.

As the ribbon was cut at exactly 10am, and shoppers filed in with a very British sense of orderly queuing, many of them read a flyer detailing the alliance's demands for a community benefits agreement making Tesco's promises both real and explicit.

The activism did not seem to deter anybody. To shoppers like Rachel Escamilla, a city bus driver who lives walking distance from the new store, the proof was going to be in the pudding – the rice pudding, organic yogurt, fresh fruit and all the other goodies she likes.

"If they have what I want, I will shop here," she said. "Up to now I've shopped at Whole Foods [the high quality grocery with high prices]. If they have the same quality stuff here for less – let's see."

Employees at the new store seemed genuinely enthused to be riding the crest of a new shopping wave, and thrilled at the zoo that rapidly developed around them as shoppers perused the English-style bacon – a hard commodity to find anywhere in the United States – the modified variants on English-style roast beef sandwiches (with a bit more roast beef than you'd find at Tesco Metro stores), the guava and mango nectars, and the free handouts of yogurt and chicken tortilla soup.

The 30-40 activists leafleting outside are not to be underestimated, however. The alliance was responsible for keeping Wal-Mart, the world's largest retailer, out of an inner-city neighbourhood and now wants Tesco to put its money where its mouth is when it says it will serve the most blighted parts of the city like South LA.

"We're not trying to boycott," the Alliance's spokesman, Greg Good, said. "But the world's third largest retailer has at least a moral obligation to sit down with the local community. To say people shouldn't worry and just trust them is a lot to ask."

A study by researchers at LA's Occidental College over the summer found that of the first 98 Fresh & Easy sites announced by Tesco, just 10 were in low-income, high-poverty areas, and only one was in an area without a full-service grocery. The first six are all in relatively comfortable suburbs.

The Occidental researchers also found that Tesco intended to employ large numbers of part-time workers, raising questions about the company's commitment to health and other benefits.

On Wednesday, about 100 alliance activists attempted to picket a company party at the Glassell Park store but were kept off the premises by security guards. A rabbi and the head of the county labour federation tried to deliver a message to the chief executive of Tesco's US operation, Tim Mason, but were turned away. "That was disrespectful, and disappointing," Mr Good said.

Yesterday, they were joined by carpenters' union members upset at the behaviour of a Tesco subcontractor at a branch in Upland in the eastern LA suburbs. "Fresh & Easy has an obligation to the community to see that area labour standards are met," the carpenters' flyer said.

It was not clear how many people were listening to these grievances, however. Linda Gutierrez, a Glassell Park community business leader, was delighted someone had replaced two supermarkets that had closed recently. "We have been waiting for any kind of company to come in and revitalise our community," she said. "This is a wonderful start."

But even she said there were issues to discuss with Tesco.

Rachel Escamilla, the bus driver, pronounced herself pretty happy after her inaugural shop. She found organic ketchup but was disappointed at the lack of crunchy almond butter – the store stocked only smooth.