The Analysis Of Pollution And Preventtion Measures Of Bacillus Cereus In Goat Milk Powdered Infant Formula Production Factories

Infant formula food is a kind of special food that has attracted people's attention and it is also one of important sources of food for infants and young children.Shaanxi Province is the dominant goat milk producer in China.Bacillus cereus is a conditional pathogenic bacterium that with highly viscous spores,so it can widely spread in the environment.Food safety is critical,and the presence of B.cereus strains in infant goat milk powder presents a great risk for infants,who are the most vulnerable group in society.In infants,infection with B.cereus may cause septicemia,bacteremia,or even meningitis.Controlling contamination in goat milk manufacturing environments represents an important first step to reducing the risk of contaminating goat milk powdered infant formula?PIF?.The processing techniques of goat milk PIF,together with personnel movement?workers'shoes,clothes,and hands?and material transport?transmission belts and cars?,as well as the manufacturing environment of the three goat milk powder factories with different production scales in Shaanxi Province?referred to as plants A,B,and C?were considered for sample collection in three consecutive months in this study.The aim was to characterize B.cereus strains from the inner contaminantion sources?including wet-mixing and dry-mixing process?and outer contaminantion sources?i.e.raw materials and ingredients,soil surrounded processing plants,and processing water?,and to infer potential contamination pathways in the production of goat milk PIF by genetic subtying.Combined with its contamintaion and subtypes,this study could provide the control technology and technical support for dairy enterprises.The conclusions are as follows:?1?Of 970 samples,350?36.1%?samples were positive for B.cereus,including 83?40.5%?of 205 samples from plant A,94?29.1%?of 323 samples from plant B,and 173?39.1%?of 442 samples from plant C.The contamination rate of goat milk PIF was 46.7%?7/15?,?1100 MPN/g.?1?Results showed that the highest contamination rate of inner contaminant sources was 40.3%?52/129?isolated from fluidized bed drying area.Regarding sampling types,the highest contamination rate was the swab samples?44.8%,235/525?.?2?Regarding outer contaminate sources,the highest contamination rate was 60%?9/15?isolated from oil in raw materials.?3?No isolates?0.0%,0/12?were obtained from fresh goat milk.?2?The RAPD profiles of the 351 total strains,including 350 B.cereus strains from the infant goat milk powder processing area and the standard strain CGMCC 1.1846,subjected to RAPD analysis that exhibited a similarity of 92.6%,but strains 3L4,3L47,5L45,2L21,1L63,and 3L33 were excluded from the clusters.Strains 3L4,3L47,5L45,2L21,1L63,and 3L33were excluded from the clusters.A total of 83 isolates from plant A,subjected to RAPD analysis that exhibited a similarity of 93.6%.The similarity of all dendrograms for isolates within each cluster S1,S2,and S3 was?95.0%,but strains 1S21 and 4S24 were excluded from the clusters.A total of 94 isolates from plant B,subjected to RAPD analysis that exhibited a similarity of 94.3%.A total of 173 isolates from plant C,subjected to RAPD analysis that exhibited a similarity of 93.3%.?3?The results of genetic diversity showed that?1?The isolates from goat milk PIF production process were divided into 7 ST types,which were ST-770?4.8%,2/42?,ST-1000?71.4%,30/42?,ST-1084?9.5%,4/42?,ST-1348?2.4%,1/42?,ST-1349?2.4%,1/42?,ST-1350?2.4%,1/42?,and ST-1351?7.1%,3/42?.ST-1000 was the main ST type of isolates in final profucts and cross-contamination occurs in processing workshops.?2?Four new ST types and four new alleles were found,which shows evolutionary variation.?3?Isolates were identified as 205,142,23 three different clonal groups,2 single-state groups?ST-770 and ST-1351?and 2 single strain?ST-1348 and ST-1349?.?4?The optimized prevention measures for the control of B.cereus from production of goat milk PIF were as follows:?1?The optimum CIP system was hot water pre-rinse-alkali cleaning?1.5%NaOH,65°C,30 min?-hot water rinse-acid Cleaning?1%HNO3,65°C,10min?-hot water rinse.?2?For the oil with the highest pollution rate among raw materials,in addition to the use of optimized CIP solutions for production,it is also necessary to strictly control the source of ingredients and strengthen the quality inspection of raw materials and ingredients.?3?The strict sanitary management of dry and wet areas in production areas should be strengthened.The clean and non-clean areas should be strictly separated and the materials'room should be clean and sanitary.?4?Strengthen personal hygiene management of production personnel.?5?Strengthen the workshop ultraviolet sterilization and O₃sterilization and take effective control.In summary,the prevention and control of Bacillus cereus in factories should cover all aspects of?human,machine,material,method,and points?to achieve effective prevention and control.