Note 11 - Business Segment Reporting - Operations by Business Segment (Details) - USD ($)	3 Months Ended		6 Months Ended
	Nov. 27, 2016	Nov. 29, 2015	Nov. 27, 2016	Nov. 29, 2015
Net sales	$ 135,865,000	$ 140,441,000	$ 268,259,000	$ 275,796,000
International sales	45,954,000	43,972,000	94,179,000	90,248,000
Gross profit	18,953,000	17,265,000	40,097,000	35,242,000
Net income (loss)	1,326,000	1,868,000	4,638,000	4,820,000
Depreciation and amortization	2,560,000	2,128,000	5,110,000	4,339,000	[1]
Dividend income	413,000	413,000	825,000	825,000
Interest income	3,000	16,000	7,000	47,000
Interest expense	380,000	439,000	1,032,000	941,000
Income tax expense (benefit)	693,000	1,069,000	2,582,000	2,760,000
Packaged Fresh Vegetables [Member]
Net sales	97,978,000	107,164,000	193,923,000	210,870,000
International sales	16,422,000	19,800,000	34,266,000	40,605,000
Gross profit	12,001,000	9,979,000	26,407,000	23,231,000
Net income (loss)	(250,000)	(658,000)	2,073,000	2,602,000
Depreciation and amortization	1,792,000	1,448,000	3,612,000	3,015,000
Dividend income	413,000	413,000	825,000	825,000
Interest income	3,000	16,000	7,000	22,000
Interest expense	122,000	410,000	671,000	877,000
Income tax expense (benefit)	(142,000)	(16,000)	513,000	905,000
Food Export [Member]
Net sales	25,701,000	22,140,000	49,040,000	44,484,000
International sales	25,701,000	22,140,000	49,040,000	44,484,000
Gross profit	1,850,000	1,676,000	2,878,000	2,679,000
Net income (loss)	733,000	1,176,000	928,000	1,277,000
Depreciation and amortization	2,000		3,000	1,000
Dividend income
Interest income
Interest expense
Income tax expense (benefit)	207,000	161,000	262,000	189,000
Biomaterials [Member]
Net sales	11,931,000	10,249,000	24,263,000	19,047,000
International sales	3,831,000	2,032,000	10,873,000	5,159,000
Gross profit	4,938,000	4,881,000	10,060,000	8,096,000
Net income (loss)	1,312,000	1,393,000	2,555,000	1,461,000
Depreciation and amortization	719,000	641,000	1,431,000	1,246,000
Dividend income
Interest income				25,000
Interest expense	(90,000)	29,000	13,000	64,000
Income tax expense (benefit)	388,000	393,000	738,000	412,000
Corporate Segment [Member]
Net sales	255,000	888,000	1,033,000	1,395,000
International sales
Gross profit	164,000	729,000	752,000	1,236,000
Net income (loss)	(469,000)	(43,000)	(918,000)	(520,000)
Depreciation and amortization	37,000	39,000	64,000	77,000
Dividend income
Interest income
Interest expense	348,000		348,000
Income tax expense (benefit)	$ 240,000	$ 531,000	$ 1,069,000	$ 1,254,000

[1] See Note 1 - Organization, Basis of Presentation, and Summary of Significant Accounting Policies for a discussion of accounting principles adopted during the period.