AGRICULTURE HANDBOOK 134, U.S. DEFF. OF AGRICULTURE 



92 



Bulk-stored sirup can be kept free from sur- 

 face infection with spoilage micro-organisYns by 

 irradiating the surface of the sirup with germi- 

 cidal lamps that emit low ultraviolet radiation, 

 particularly in the region of 260 millimicrons 

 {133). The lamps must be mounted to illuminate 

 the entire surface of the sirup (chart 21). 



CAUTION 



Never expose the eyes to radiation fi-om 

 gennieidal lamps sinee pennanent dam- 

 age ean result. Always turn tli«' lights off 

 before working in the area illuminated hy 

 these lamps. 



Size and Type of Paekage 



The size and type of package are important 

 when sirup is made for retail sale. Housewives 

 dislike to repackage sirup from a gallon con- 

 tainer to smaller ones for use as occasion de- 

 mands. This has been demonstrated by the 

 growing tendency on the part of the public to 

 buy maple sirup in quart or even smaller pack- 

 ages. 



The net weights for standard-density sirup 

 are: 1 gallon weighs 11 pounds; 1 quart weighs 

 2 pounds and 12 ounces; 1 pint weighs 1 pound 

 and 6 ounces. Since sirup must be packed hot 

 (180° F. or above), the capacity of the container 

 must be at least large enough to allow for the 

 volume of the heat-expanded sirup. The volume 

 of 11 pounds of standard-density sirup is 231 

 cubic inches at 68° F. (20° C); its volume at 

 212° F. is 239.9 cubic inches. Thus, a gallon 

 container should have a minimum capacity of 

 241+1 cubic inches; quart containers, 60.2t0.5 

 cubic inches; and pints, 30.1±0.5 cubic inches. 



Consumers expect sirup to be as attractively 

 packaged as other foods (fig. 103). When sold at 

 roadside stands, sirup packaged in tin con- 

 tainers is attractive to tourists regardless of 

 the size of the container, because they do not 

 have to take special care in storing tin con- 

 tainers in the car as they must with glass 

 containers. All metal containers should be care- 

 fully inspected before they are filled to be sure 

 they are free of all foreign matter and contain 

 no insects or rodents or their debris. 



ULTRAVIOLET 

 TUBE 



REFLECTOR 



COVER 



Chart 21. — Ultraviolet (germicidal) lamp must be posi- 

 tioned to illuminate the entire surface of the sirup. 

 More than one lamp may be required. 



Both glass and tin packages should be attrac- 

 tively labeled. The printed label must be put on 

 squarely, and the outside must be clean. Many 

 producers are finding that cans with the labels 

 lithographed on the tin make an ideal package. 



Suiiiiiiai^ 



(1) Package sirup hot (180° F. or above). 



(2) Do not reheat sirup above 200°. 



(3) Fill sirup package by weight rather than 

 by volume. 



(4) In packaging by weight, allow for the 

 weight (tare) of the container. 



(5) Use scales that have been tested and cali- 

 brated against certified weights. 



(6) Avoid stack bum by cooling the packaged 

 sirup before close stacking it. 



(7) Control mold gi-owth in cold-packed sirup 

 or in sterile sirup that has been opened 

 and exposed to infection by inverting the 

 container once a week. 



(8) Yeast spoilage can be prevented only by 

 hot packing. 



(9) The chemical inhibitor sodium propyl 

 PHBA in 0.02- percent concentration is ef- 

 fective in controlling mold and yeast 

 growth in sirup. CAfT/O.V— Obtain State 

 and Federal approval before use. 



