Our strong relationship and improved ability to serve the customers is reflected in our third quarter performance, in seven of our 10 largest categories we outperformed private label, a trend that we've seen over the last year.
Third quarter revenue of $1.1 billion grew 5.3% versus last year.
On an organic basis, revenue grew 1.7% and was driven by pricing of 3%.
Third quarter adjusted EBITDA was $109 million.
Adjusted EBITDA margin of 9.9% declined 320 basis points, driven by inflation, labor and supply chain disruption.
We delivered adjusted diluted earnings per share in the third quarter of $0.46, within the range of our guidance that we communicated in August.
Bill will get into this more, but we estimate that in the third quarter we had roughly $40 million in unmet demand due to constraints across the network, either not being able to run lines to the lack of labor or because we didn't have the appropriate supplies.
We are a complex supply chain business with 29 categories and 40 plants as we are organized today.
On Slide 8, you see that third quarter revenue was $1.1 billion, up 5.3% versus last year, of which 3 points was pricing related and we've been able to service a $40 million of revenue as Steve mentioned earlier, we would have delivered the top end of our revenue guidance in the quarter.
On Slides 9 and 10, we have provided revenue by division and by channel.
Meal prep net sales grew 7.4%, elevated by 5.2 points from the past the pasta acquisition.
Organic sales were nearly 2%, of which 4.6 points was pricing.
Volume and mix declined 2.8 points, driven by supply chain constraints and partially offset by the continued improvement in the food-away-from-home channel.
Snacking & beverage revenue grew 2%, of which 1.1% was driven by volume and mix and in particular, new product introductions.
Sild 10 details our topline by channel.
The unmeasured retail channel, which includes key retailers in the value club and online space continue to drive growth of 6% this quarter.
This compares to a decline of 2% in the measured channels, a sequential improvement over the second quarter.
Volume and mix, including absorption were a negative $0.26 of impact.
In the third quarter, pricing contributed $0.43, partially offsetting inflation we incurred in the first half of the year.
In the third quarter, the higher input cost was a negative $0.88.
Total PNOC or the net of these two is negative $0.45.
Also in the third quarter operations contributed $0.22 in total versus last year.
While the comparison to the prior year is positive, the COVID related disruption impacting labor and the supply chain cost the company by about $0.07 in the quarter.
Across our 29 categories and 40 plants, we have been working hard to mitigate the impact.
SG&A was a benefit of $0.16.
Finally, interest expense favorability contributed $0.08 in the quarter versus last year.
In the last 12 months, we paid down more than $300 million in debt, reducing total debt from $2.2 billion dollars to $1.9 billion.
We've also reduced our weighted average cost of debt by 100 basis points with the refinancing completed earlier this year.
This action lowered our annual interest cost by approximately $20 million.
So between cash on hand and the revolver, we have strong liquidity of nearly $800 million.
Financial leverage in the third quarter was 3.9 times as we build inventory to prepare and anticipate continued supply chain interruption.
Similar to Q3, we anticipate we'll have some limitations on our ability to meet all demand indicated by our customer orders and we think revenue in 2021 will be in the $4.20 [Phonetic] to $4.325 billion.
While we are exploring many avenues to mitigate the lack of labor availability and supply chain dynamics, in the near-term our cost of service to customer will be significantly higher as a result of these factors, we are reducing our EBIT guidance $155 million to $175 million, which compares to $230 million to $260 million previously.
This translates into full year adjusted earnings per share of $1.08 to $1.28, down from our revised August guidance of $2 and $2.50 per share.
We are reducing our 2021 free cash flow guidance to at least $100 million.
Slide 14 covers our fourth quarter guidance and our expectation for adjusted earnings per share between $0.00 and $0.20.
On Slide 15, we started with our February EBIT guidance of approximately $300 million because we believe that this is a much closer and normalized annual level of profitability for the company.
We've talked in August about this impacting revenue in both the quarter and the year and we estimate this to be a $40 million impact to EBIT this year.
Our original guidance contemplated input cost headwinds of approximately $100 million to $110 million.
The additional inflationary headwind is another $125 million, more than double our original estimate.
Our realized Q3 price increase of 3% is expected to accelerate to 4% to 5% in Q4, building to low-double digits in 2022.
We estimate that the timing lag in calendar '21 is approximately $75 million.
these challenges are especially acute across our 40 plant network.
We estimate that the incremental cost this year is approximately $60 million.
We've also captured the benefit of the reversal of the variable compensation accrual of $35 million.
The net of these factors represent the near-term impact that has driven our 2020 EBIT guidance to $165 million at the midpoint.

Summary:
Third quarter revenue of $1.1 billion grew 5.3% versus last year.
We delivered adjusted diluted earnings per share in the third quarter of $0.46, within the range of our guidance that we communicated in August.
Similar to Q3, we anticipate we'll have some limitations on our ability to meet all demand indicated by our customer orders and we think revenue in 2021 will be in the $4.20 [Phonetic] to $4.325 billion.
This translates into full year adjusted earnings per share of $1.08 to $1.28, down from our revised August guidance of $2 and $2.50 per share.