Kyohei Kiyota1, Yuka Fujiwara2, Kazuto Adachi2, Makoto Kameda3, Kazuhiko Akutsu1, Keiji Kajimura1. 1. Division of Food Chemistry, Osaka Prefectural Institute of Public Health. 2. Central Region Block, Osaka Prefectural Council of Food Sanitation Inspectors. 3. Osaka Prefectural Medical Center for Respiratory and Allergic Diseases.
Abstract
BACKGROUND: In May 2012, two schoolchildren developed allergic symptoms after eating a school meal of fried bread in Osaka, Japan. One specific raw material, milk, should not be present in fried bread. However, we suspected the unintentional mixing of milk in the bread manufacturing process. Our aim was to verify the reason if this was so. METHODS: We first manufactured bread that contained milk as one of its components. We then thoroughly cleaned the manufacturing line except for the dough divider and, as per the revised instruction manual, continuously manufactured bread that did not contain milk. In this manner, we tried to simulate the conditions at the time of the incident. Casein is a major milk protein. We, therefore, determined casein concentration in the milk-free bread, using casein enzyme-linked immunosorbent assay. RESULTS: We observed casein levels higher than 1000 ppm in the initial lots of breads, but lower levels in the later lots. Casein levels also decreased upon frying of bread. CONCLUSION: High casein levels, which were observed in the earlier lots of breads, were lower in the later lots. In the manufacturing line, the remnants of the bread dough that contained milk presumably got mixed with the dough used in the subsequent manufacture of milk-free bread.
BACKGROUND: In May 2012, two schoolchildren developed allergic symptoms after eating a school meal of fried bread in Osaka, Japan. One specific raw material, milk, should not be present in fried bread. However, we suspected the unintentional mixing of milk in the bread manufacturing process. Our aim was to verify the reason if this was so. METHODS: We first manufactured bread that contained milk as one of its components. We then thoroughly cleaned the manufacturing line except for the dough divider and, as per the revised instruction manual, continuously manufactured bread that did not contain milk. In this manner, we tried to simulate the conditions at the time of the incident. Casein is a major milk protein. We, therefore, determined casein concentration in the milk-free bread, using casein enzyme-linked immunosorbent assay. RESULTS: We observed casein levels higher than 1000 ppm in the initial lots of breads, but lower levels in the later lots. Casein levels also decreased upon frying of bread. CONCLUSION: High casein levels, which were observed in the earlier lots of breads, were lower in the later lots. In the manufacturing line, the remnants of the bread dough that contained milk presumably got mixed with the dough used in the subsequent manufacture of milk-free bread.