14 BULLETIN 531, U. S. DEPARTMENT OF AGRICULTURE. 



siderable decay, but none of the berries so treated developed into 

 typical leaks within 48 hours after removal from the refrigerated 

 container, and the presence of black dirt in the wounds was mis- 

 leading- and made the accurate sorting of these berries difficult. 



The above experiments indicate that the fungus in question is not 

 of primary importance as a field rot, that usually it does not enter 

 the berries from the soil, and that in the localities investigated infec- 

 tion occurs at some time after picking. 



UNSANITARY CONDITIONS USUALLY PREVAILING IN THE PACKING HOUSE. 



Conditions in and around the packing house often are unsanitary, 

 favoring the growth and distribution of Ehizopus, and the frequent 

 handling and consequent bruising which the berries often undergo 

 would seem to offer many chances for infection. The culls often are 

 thrown on the ground near the packing house; various fungi, includ- 

 ing Rhizopus, may be found fruiting on these discarded berries. 

 Packing tables become soaked with strawberry juice and usually are 

 not cleaned or disinfected during an entire season. When berries are 

 washed, a few gallons of water are placed in a tub and used for all 

 berries cleaned during the day. Fungus spores, soil, and other dirt 

 soon accumulate in this wash water, and apparently might by this 

 means be distributed generally over a large proportion of the fruit. 



Conditions in packing houses and cars as regards infection from 

 Rhizopus can be easily improved bj T the frequent use of hot water. 

 The recent work of Thorn and Ayers (16) shows that the spores of 

 this fungus are easily killed by heat when wet, but are more resistant 

 in dry air. Rhizopus spores (16, p. 159) were killed in 30 seconds 

 at a temperature of 115° F. in milk, but survived a temperature of 

 200° F. when dry. It is probable, however, that even with the 

 greatest care all sources of fungous growth and distribution can not 

 be eliminated. 



THE BRUISING OF BERRIES IN PACKING. 



It has been shown that Rhizopus rarely, if ever, enters berries 

 through the unbroken epidermis; care to avoid bruising is therefore 

 of great importance. This fact was emphasized by an experiment 

 in which sound berries were Avrapped individually in tissue paper, 

 carefully packed, and shipped to Washington. It was found that 

 fruit so treated could be held at room temperature for a week or 

 more after arrival without the appearance of decay, while similar 

 berries packed and shipped in the commercial manner were badly 

 rotted within 48 hours after reaching their destination. 



Berries are injured to some extent every time they are handled or 

 shaken. When possible, especially when shipments are made in car 

 lot- under refrigeration, it is preferable to ship in the containers in 



