Days sales outstanding estimates how long, on average, your receivables take to turn into cash. A common formula is accounts receivable divided by credit sales for the period, multiplied by the number of days in the period.
DSO matters more in food distribution than in many industries because margins are thin and inventory turns fast. You pay suppliers on their terms while your customers pay on theirs; every extra day of DSO is working capital you are lending to customers.
DSO is a trend to watch, not a single number to hit. It moves with your mix of customers and terms. Pair it with an AR aging report to see whether a rising DSO comes from a few large late payers or from slower payment across the book.