Andronicos Sideras, 55, is accused of mixing horsemeat with beef before selling it on through his company Dinos & Sons.
Two men who ran FlexiFoods - a meat suppliers linked to Dinos & Sons - have admitted passing horsemeat off as beef.
Mr Sideras denies one count of conspiracy to defraud.
The discovery of horsemeat in processed beef products sold by a number of UK supermarket chains in 2013 resulted in a series of product recalls.
The plot to pass horsemeat off as beef only came to light after horse identification chips were found in the meat by inspectors.
Ulrik Nielsen, 58, the owner of FlexiFoods, and his "right-hand man", Alex Beech, 44, have already admitted their involvement in the conspiracy.
Mr Sideras, of Southgate, north London, told the court in that in 2012 he agreed to store horsemeat for FlexiFoods.
He admits he relabelled the shipment because the packaging had been damaged during transit, but denies purchasing, selling or using the horsemeat.
The trial continues.

MI6 and and GCHQ advertised on the Mumsnet website for the first time this year, and MI5 has raised its target for women employees to 45% by 2021.
Flexible working and the importance of "high emotional intelligence" are also being stressed in recruitment.
The agencies were responding to calls from MPs to recruit more women.
Parliament's Intelligence and Security Committee reported in March 2015 that 37% of intelligence agency staff were women and women only make up 19% of senior civil servants in the agencies.
One year on, the government says that it and the agencies - internal security service MI5, external spy agency MI6 and the government listening post GCHQ - "agree wholeheartedly" with the need for "diversity" in agency staff.
It says action has been taken since the report was published to "increase their focus" on "all aspects of diversity", including recruiting more women.
Recruitment targets, "diversity champions", events such as a recent "Women in Cyber" event and more career support for female officers are part of efforts to employ more women and encourage talented existing women to apply for promotion.
They also say they are doing more to "promote a flexible working culture" for men and women with childcare commitments and to allow women returning from maternity leave to take up their old jobs - including in intelligence roles.
The three agencies also said they were always looking for "new and innovative ways to recruit those with the right skills, mind-set and diversity of approach".
MI5 had already used Mumsnet as well as local newspapers to target women "not currently in work" while the other two agencies did so for the first time this year.
GCHQ has also removed a requirement of a 2:1 university degree from its "fast-stream" recruitment to encourage women who had followed a "non-traditional graduate route".
The government said the initiatives were having an effect as MI5 had recently been placed in the Times Top 50 employers for women and had increased its number of new female employees by 5% to 46% of new recruits. GCHQ had seen applications from women rise to 40%. MI6 had increased its female recruitment targets for 2016/17 after seeing a 4% drop in women - to 41% of new recruits.
The government also said career support for female staff was having a "real impact" with increased numbers of women applying for senior roles in MI5.

Marsh failed to score in 16 league games after joining Dover from Torquay for an undisclosed fee in January 2016.
The 23-year-old made eight appearances for Dover last season, but finished the season on loan at National League South side Welling United.
Marsh is Macclesfield manager John Askey's 10th signing since the end of last season.
Find all the latest football transfers on our dedicated page.
A businessman has denied being part of a conspiracy to pass off horsemeat as beef, claiming he was only storing the product for another company.
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UK intelligence agencies say they are recruiting more female staff - and are targeting middle-age and "mid-career" women for jobs.
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Macclesfield have signed striker Tyrone Marsh on a one-year contract after he left National League rivals Dover.