Mason, from Deri, Caerphilly county, died after contracting the bug's 0157 strain in 2005.
Ms Mills said the report recommendations "need to be implemented immediately as this is the only way to ensure that public safety is protected".
She added: "The report shows that butcher William Tudor was to blame for the outbreak but also that public authorities needed to do more to protect us all.
"My son would be alive today if proper systems had been put in place in 2005 to avoid cross-contamination in food processing and the systems need to be put in place as soon as possible so no-one has to go through such a tragedy again."
Prof Hugh Pennington has called for better implementation of food hygiene procedures
First Minister Rhodri Morgan said the Welsh Assembly Government, which commissioned the inquiry, would work with enforcement agencies to ensure the public's safety.
Even though the risk of another outbreak could not be wholly eliminated, he said he hoped to minimise the chances of it happening again.
Forty-four schools across the south Wales valleys were affected in the outbreak and 156 people were made ill.
It was the largest outbreak of its kind in Wales, the second biggest in the UK and the sixth largest worldwide.
E.COLI PUBLIC INQUIRY
157 confirmed E.coli cases
Most cases in children in 44 schools across four local authority areas - Bridgend, Caerphilly, Merthyr Tydfil and Rhondda Cynon Taf
Thirty-one people admitted to hospital, mostly children. One death
More than 45,000 pages of evidence reviewed
258 statements from 191 witnesses (excludes statements taken by South Wales Police)
63 witnesses called during an extensive six-week programme of public hearings
Source: The public inquiry team
Prof Pennington, a microbiologist who also investigated an E.coli outbreak in Lanarkshire in 1996, chaired the inquiry into the south Wales outbreak.
Twenty-one elderly people died in the Lanarkshire outbreak after eating contaminated meat from a Wishaw butcher.
Photos shown during the inquiry into the south Wales outbreak, which finished last May, revealed unhygienic conditions at the butcher's premises, with congealed blood on machines and pieces of raw meat left on the floor.
Prof Pennington said the outbreak was "particularly shocking" because the systems regulating food safety at the time had been reformed as a result of the 1996 outbreak.
He said the only systems which did their job in the outbreak were in control and clinical, and there had been failures everywhere else.
"We owe it to the memory of Mason Jones to learn the lessons from this outbreak and to remember them," said Prof Pennington.
He made 24 recommendations in his report but said the requirements for food hygiene in place at the time of the outbreak should have been sufficient to prevent it.
His report found there were serious and repeated breaches of food safety regulations at Tudor's premises, and that the butcher had "falsified certain records that were an important part of food safety practice".
The inquiry heard that Tudor "misled and lied to" environmental health inspectors and that "deficiencies had been there for a long time before".
Prof Pennington also criticised inspectors from Bridgend council for not assessing or monitoring the firm's management of food safety "as well as they could or should have done".
The fundamental flaws in John Tudor and Sons' hazard analysis critical control point (HACCP) plan, which delivers food safety, were also missed, he said.
The process by which meat supply contracts were awarded to John Tudor and Son in 1998 and 2002 by Rhondda Cynon Taf, Bridgend, Caerphilly and Merthyr Tydfil councils were "seriously flawed", said the report.
"If anything was likely to have encouraged William Tudor to get his act together on food hygiene, it would have been the direct threat of failing to secure, or losing, what was a very significant contract," said Prof Pennington.
He also criticised the Meat Hygiene Service for allowing JE Tudor & Sons abattoir, which supplied meat to John Tudor & Son, to continue functioning in breach of legislative requirements.
However Prof Pennington did praise the work of the outbreak control team, saying they reacted quickly to remove cooked meats from the food chain.
He said: "But for the quality of the analysis and control measures, the outbreak would have been considerably more severe and prolonged."
Prof Pennington recommended that resources be made available to ensure businesses got to grips with food safety management.
He also said the Food Standards Agency should review its current guidance. In terms of food safety inspections, officers who check HACCP plans and their overseers should get more training, said Prof Pennington.
Procedures to log issues and concerns about firms' food safety should become common practice for these officers, he said.
He also called for all inspections to be unannounced unless there were circumstances where a visit had to be pre-arranged.
All local authorities in Wales should review their policies, procedures and systems against the issues identified in the report, he said.
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