long-term debt outstanding during the fourth quarter of 2021 as compared to the fourth quarter of 2020, primarily as a result of incremental borrowings the Company made in the fourth quarter of 2020 to fund the Crisco acquisition and related fees and expenses. The increase in net interest expense was partially offset by a lower effective cost of borrowing during the fourth quarter of 2021.
The Company’s net loss was $4.8 million, or $0.07 per diluted share, for the fourth quarter of 2021, compared to net income of $12.2 million, or $0.19 per diluted share, for the fourth quarter of 2020. The Company’s adjusted net income for the fourth quarter of 2021 was $26.3 million, or $0.39 per adjusted diluted share, compared to $22.8 million, or $0.35 per adjusted diluted share, for the fourth quarter of 2020. The net loss and diluted loss per share for the fourth quarter were primarily attributable to non-cash impairment charges to trademarks for the Static Guard, SnackWell’s, Molly McButter and Farmwise brands of $23.1 million in the aggregate during the fourth quarter of fiscal 2021, partially offset by the positive impact of the Crisco acquisition. The increases in adjusted net income and adjusted diluted earnings per share for the fourth quarter were primarily attributable to the positive impact of the Crisco acquisition, partially offset by the negative impact of industry-wide input cost inflation and supply chain disruptions.
For the fourth quarter of 2021, adjusted EBITDA was $85.1 million, an increase of $11.8 million, or 16.0%, compared to $73.3 million for the fourth quarter of 2020. The increase in adjusted EBITDA was primarily attributable to the positive impact of the Crisco acquisition, partially offset by industry-wide input cost inflation and supply chain disruptions. Adjusted EBITDA as a percentage of net sales was 14.9% for the fourth quarter of 2021, compared to 14.4% in the fourth quarter of 2020.
For the fourth quarter of 2021, adjusted EBITDA before COVID-19 expenses1 was $85.5 million, an increase of $7.9 million, or 10.1%, compared to $77.6 million for the fourth quarter of 2020. COVID-19 expenses were $0.4 million and $4.3 million for the fourth quarter of 2021 and the fourth quarter of 2020, respectively. Adjusted EBITDA before COVID-19 expenses as a percentage of net sales was 14.9% for the fourth quarter of 2021, compared to 15.2% in the fourth quarter of 2020.
Financial Results for the Full Year Fiscal 2021
Net sales for fiscal 2021 increased $88.4 million, or 4.5%, to $2,056.3 million from $1,967.9 million for fiscal 2020. The increase was primarily due to the Crisco acquisition, largely offset by comparisons against the extraordinary demand resulting from the COVID-19 pandemic during fiscal 2020, one fewer reporting week in fiscal 2021 compared to fiscal 2020, and supply chain disruptions in the fourth quarter of 2021 resulting from the COVID-19 Omicron variant. The Company estimates that the additional week in the third quarter of 2020 contributed approximately $35.0 million to the Company’s net sales for fiscal 2020. An extra eleven months of net sales of Crisco, acquired on December 1, 2020, contributed $255.7 million to the Company’s net sales for fiscal 2021. Net sales for fiscal 2021 were 23.8% higher than pre-pandemic net sales for fiscal 2019. On a two-year compound annual growth basis, net sales for fiscal 2021 increased 11.3%.
Base business net sales1 for fiscal 2021 decreased $162.1 million, or 8.3%, to $1,798.1 million from $1,960.2 million for fiscal 2020. The decrease in base business net sales reflected a decrease in unit volume of $222.6 million, partially offset by an increase in net pricing and the impact of product mix of $54.3 million, or 2.8% of base business net sales, and the positive impact of foreign currency of $6.2 million. Base business net sales for fiscal 2021 were 5.2% higher than pre-pandemic base business net sales for fiscal 2019. On a two-year compound annual growth basis, base business net sales increased 2.6%.
Net sales of the Company’s spices & seasonings3 increased $4.6 million, or 1.2%, and net sales of Maple Grove Farms increased $4.5 million, or 5.9%, in fiscal 2021, as compared to fiscal 2020. Primarily as a result of the tough comparisons against fiscal 2020 due to the COVID-19 pandemic, one fewer reporting week in fiscal 2021 compared to fiscal 2020, and supply chain disruptions, net sales of Green Giant (including Le Sueur) decreased $95.1 million, or 14.9%; net sales of Clabber Girl decreased $17.9 million, or 18.4%; net sales of Ortega decreased $7.1 million, or 4.5%; and net sales of Cream of Wheat decreased $5.5 million, or 7.6%, in fiscal 2021, as compared to fiscal 2020. Base business net sales of all other brands in the aggregate decreased $45.6 million, or 8.3%, for fiscal 2021.