拉萨地区酸奶质量安全的污染因素评价与分析

【目的】全面分析评价影响西藏拉萨四县(区)(城关区、墨竹工卡县、林周县和当雄县)不同方式生产酸奶的质量安全关键污染因素,为提高拉萨酸奶质量安全水平、强化质量安全监管提供数据支撑。【方法】2018年从拉萨四县(区)分别采集不同模式生产的酸奶样品106个,其中:林周县采样22个,城关区采样40个,墨竹工卡县采样23个,当雄县采样21个;按生产模式,企业采样8个,小作坊采样54个,家庭自产采样44个。分别使用电感耦合等离子体质谱法、HPLC-MS法、微生物培养与分离法对酸奶样品中5种重金属、黄曲霉毒素M1以及6种微生物进行检测分析与质量安全评价。【结果】106个酸奶样品中霉菌污染严重,且超标率为46.23%;未检出志贺氏菌Shigella、沙门氏菌Salmonella和黄曲霉毒素;小作坊生产的酸奶中金黄色葡萄球菌Staphylococcus aureus检出率最高,检出率为25.93%;农牧民自身生产、民间小作坊和企业产业化生产酸奶中Pb是主要重金属污染物,污染物贡献率达42.5%;当雄县酸奶中重金属Cr含量较其他三县(区)高,超标率为19.0%;城关区酸奶中重金属Pb、As含量较高,超标率分别为15.0%和2.5%;Pb也是林周县、城关区、墨竹工卡县酸奶中的主要重金属污染物,其中城关区Pb的污染物贡献率最高,达54.02%。【结论】拉萨地区酸奶重金属和霉菌污染状况突出,应当引起重视;西藏特殊的自然环境不利于饲料霉变,因此未检出黄曲霉毒素。

Evaluations and analyses of pollution factors of yogurt quality and safety in Lhasa

Objective To evaluate and analyze the key pollution factors affecting the quality and safety of yogurt collected by different production methods in four different districts (Chengguan District, Maizhokunggar County, Linzhou County and Damxung County) of Lhasa in Tibet, and provide strong data support for improving the quality and safety of Lhasa yogurt and strengthening the quality and safety supervision.Method In 2018, 106 yogurt samples with different production modes were collected from four counties (districts) of Lhasa, including 22 samples from Linzhou County, 40 samples from Chengguan District, 23 samples from Maizhokunggar County and 21 samples from Damxung County. Eight samples were collected from enterprises, 54 samples from individual workshops and 44 samples from families. Five kinds of heavy metals, aflatoxin M1 and six kinds of microorganisms in yogurt samples were detected and analyzed by ICP-MS, HPLC-MS, microbial culture and separation, respectively to evaluate the quality and safety.Result Total 106 yogurt samples were seriously contaminated by mold, and the exceeding rate was 46.23%. Shigella, Salmonella and aflatoxin were not detected in yogurt. The detection rate of Staphylococcus aureus in yogurt produced by individual workshop was the highest at 25.93%. Pb was the main heavy metal pollutant in yogurt produced by farmers and herdsmen, individual workshops and enterprises, with the contamination contribution rate of 42.5%. The content of Cr in yogurt of Damxung County was higher than those in other three counties (districts), with the exceeding rate of 19.0%. The contents of Pb and As in yogurt of Chengguan District were higher, with the exceeding rates of 15.0% and 2.5%, respectively. Pb was also the main heavy metal pollutant in yogurt of Linzhou County, Chengguan District and Maizhokunggar County, among which the contamination contribution rate of Pb in Chengguan District was the highest reaching 54.02%.Conclusion The pollutions of heavy metals and molds in yogurt of Lhasa are prominent, which should be paid attention. The special natural environment in Tibet is not conducive to the mildew of feed, so no aflatoxin is detected.