We achieved 3% in combined sales growth, or 1% in currency-neutral basis, compared to the first quarter of 2020.
Also because of our change to a fiscal calendar rather than a traditional 4-4-5 calendar, we have had less -- two days less in first quarter.
If we were to normalize for that, our combined currency-neutral growth in the first quarter would also have been approximately 3%.
And on a two-year average basis, to factor in our strong 7% year-ago comparison, growth would be strong at approximately 5%.
Our adjusted operating EBITDA margin improved by 30 basis points, reflecting our team's diligent execution of our cost management strategy.
For the first quarter, our leverage ratio was 4.3 times.
The fruit preparation business contributed approximately $70 million to IFF's Nourish segment pro forma sales in 2020.
We continued to see healthy performance across our Asian markets, achieving a 6% increase in combined currency-neutral sales, primarily driven by double-digit growth in China and India.
In Latin America, we saw an 11% increase in overall sales for the region with growth primarily driven by local currency sales.
COVID-19 and related ongoing restrictions continue to heavily impact Western and Central Europe, which has resulted in challenges across the entire EMEA region and a 5% decline in overall sales.
Our largest group, Nourish, achieved combined currency-neutral sales growth of 1%, led by robust performance in Flavors.
Scent continued its strong performance, achieving combined currency-neutral sales growth of 5%, the largest growth driver across our four divisions, led by continued strengths in Consumer Fragrances, double-digit growth in Cosmetic Actives, and a strong rebound in Fine Fragrance.
For our Pharma Solutions division, we achieved combined currency-neutral sales growth of 3%, with continued strong performance across the entire division and all sub-categories.
For Health & Bioscience division, combined currency-neutral sales decreased 3% against a strong double-digit year-ago comparison.
On the revenue synergies front, we have a robust pipeline of projects, including both cross-selling and integrated solutions, that we expect will accelerate our ability to meet our $20 million synergy target this year.
We are confident in our ability to meet our three-year run rate synergy target of $400 million.
We expect these cost savings to increase over the course of the year, putting us well on track to meet our $45 million cost synergy target in the full year 2021, and our year three run rate cost synergy target of $300 million.
In the first quarter, IFF generated $2.5 billion in sales, a 3% combined year-over-year increase, including foreign exchange benefits, or up 1% on a currency-neutral basis, primarily led by strong performances in our Scent and Pharma Solutions divisions.
Meanwhile, our aggressive cost management program led by headcounts and other expense reductions, enabled us to improve RSA to sales by 120 basis points and deliver year-on-year adjusted operating EBITDA growth of 4%.
As an aside, Q1 2020 was our most difficult comp with 7% combined currency-neutral sales growth and strong adjusted operating EBITDA growth.
IFF also delivered adjusted earnings per share, excluding amortization of $1.60 for the first quarter.
Nourish sales totaled $1.3 billion for the quarter, representing 1% growth on a combined currency-neutral basis.
Adjusted operating EBITDA grew 6%, with a 60 basis point margin expansion led by strong cost management.
As Andreas noted, H&B had a combined currency-neutral sales decline of 3%, but this was against a robust 11% positive year-over-year comparison.
It should be noted that on the two-year average basis, currency neutral growth was solid at 4%.
Adjusted operating EBITDA was also pressured and operating margin declined by 70 basis points, primarily driven by lower segment volumes and higher raw material and logistics costs.
Microbial Control & Grain Processing were also impacted by continued pre-COVID cycling, which impacted H&B's overall growth by approximately 5 percentage points.
Our Scent division generated $569 million in total sales, representing 5% combined currency-neutral growth against a strong 7% growth in the year-ago period as well.
On a two-year basis, growth is exceptional at approximately 6%.
Adjusted operating EBITDA improved 8% with a 70 basis point margin expansion predominantly driven by volume growth across the entire segment, as well as favorable mix from Fine Fragrance recovery and continued productivity.
Pharma Solutions delivered $162 million in net sales, representing 3% in combined currency-neutral growth while adjusted operating EBITDA grew 2%.
Taken in the context of the 11% growth in the prior-year period, growth is impressive on a two-year basis -- average basis at approximately 7%.
As you will see, our operating cash flow was very strong at $358 million.
A large part of our Q1 success came from core working capital, where we generated $193 million, a great job by our global team and a great outcome.
In the first quarter, capex was approximately $93 million or 3.5% of sales, up from last Q1's combined comparative $76 million or 2.6% of sales.
Free cash flow generation was, therefore, strong $265 million, and we distributed $82 million in dividends to our shareholders.
Our leverage, which is net debt divided by credit adjusted EBITDA ended at 4.3 times, as Andreas noted back on Slide 6.
This is ahead of our expectation of 4.5 times first quarter post-merger leverage.
Legacy IFF generated $520 million of free cash flow in 2020 and combined, we expect to generate $1 billion in 2021.
In 2021, we will invest more in legacy N&B production capacity to meet expected strong future demand, but will only be slightly above our original full-year capex projection of approximately 4.5% of sales.
The dividend payment this year will be -- this quarter will be $197 million reflecting our higher post-merger share count.
And we remain on track to meet our long-term deleveraging target of 3 times net debt to credit adjusted EBITDA in 24 months to 36 months from deal close.
On a combined basis, IFF generated $10.6 billion of revenue for the full year 2020, with currency neutral growth of approximately 2%.
And our combined adjusted operating EBITDA margin for 2020 was approximately 22%.
Please remember that combined includes 11 months of N&B and 12 months of IFF in 2020 and 2021.
In our fourth quarter conference call in February, we gave initial pro forma guidance, which assume the full 12 months of IFF and N&B, in order to be directly comparable to our previously provided S-4.
Moving forward, to be more aligned with actual results and reporting, we are transitioning to guiding on 11 months of N&B, which excludes January and 12 months of IFF in the 2021 year, in light of the merger completing on Feb.
Also, please note that in January 2021, N&B's actual sales were approximately $507 million and adjusted operating EBITDA was $107 million.
We have, therefore, increased our sales expectation for 2021 to be approximately $11.25 billion in combined revenues, or plus 6% growth with an approximately 23% adjusted operating EBITDA margin.
We are optimistic that for the full second quarter, revenue growth including currency benefit should be in the high-single-digits range, with an adjusted EBITDA margin also around 23%.
And the 21.5% is broadly in line with our early expectations.
The equivalent for heritage IFF on a similar basis for the full-year 2020 was approximately 18.5%.

Summary:
IFF also delivered adjusted earnings per share, excluding amortization of $1.60 for the first quarter.
Please remember that combined includes 11 months of N&B and 12 months of IFF in 2020 and 2021.
We have, therefore, increased our sales expectation for 2021 to be approximately $11.25 billion in combined revenues, or plus 6% growth with an approximately 23% adjusted operating EBITDA margin.