The firm behind the Strongbow and Scrumpy Jack brands said it had reviewed procedures after the conspiracy had been discovered.
The failed attempt at contamination ended with Michael Hancocks, a major shareholder of rival firm Aston Manor Brewery, being jailed for 18 months.
Bulmers PR manager George Thomas said the trade had no cause for concern.
“As a result of the incident two years ago we have imposed even stricter security. Quality remains at the highest possible standard.”
The plot was the result of a bitter feud between Aston Manor and Bulmers, which dates back to 2001 when both companies were competing for a supply contract with Booker.
Bulmers went on to win the most profitable part, prompting Hancocks, from Hereford, to devise a plot to contaminate the production line with a yeast-based bacteria.
The plot failed after the Bulmers factory worker recruited to administer the contaminate informed his line manager who then called in police.