Mizkan Holdings said it would suspend sales of four of its natto products from this month due to supply constraints. The Aichi Prefecture-based foodmaker said Friday that prolonged geopolitical tensions in the Middle East have driven up prices and heightened supply risks for naphtha, a key feedstock used in petrochemical products such as packaging materials. As a result, procurement costs have increased, putting a strain on packed natto production, Mizkan said. Separately, the company said it would raise prices on all 19 of its natto products starting June 1, with reference retail prices, excluding tax, set to increase by between 6% and 20%. Mizkan said it had tried to absorb the higher costs but determined that maintaining product supply under the current pricing structure had become difficult. The company also warned that further price revisions or supply impacts could occur depending on future trends in raw material and energy costs.…