第一步，拿食品。当我们找到了我们想要的食品时，大家一定都会看到那些食品会被陈列得很整齐，一般而言，当我们为了方便时往往是直接拿排列在最外面的食品，在商店买东西时他们是不会买过期食品的，因为那是违法的，商家往往会买给消费都快要过期的食品，也就是说要报废的食品。商家会把快要过期的食品放在最外面，是拿食品时最好是拿放在最里面的食品。
第二步，看日期。在食品包装上面大多数都会写着生产日期和到期时间，这种类型的食品一看就能知道是否有多少时间才会过期，还有一种就是只写着生产日期，保质期却没有写着到期日期的，我们要根据食品的保质期来算时间。这样你就能明确的掌握了食品的过期时间。
第三步，问商家。当你要买的食品也许做法的不同等原因导致完全没有看到生产日期等时间，当遇到这种情况时，你要部商家这食品的生产时间，保质期是多少，要了解清楚。再根据自己的购买要求来判断要不要购买，同时了也要问清楚要如何保存食品。
第四步。食品样。生产日期，保质期等，都是可以做假的，所以我们去买食品时也要注意一个食品样，如何你发现食品外有不妥或发霉或溢水等。如果可以的话，可以经过手摸食品或是闻味道来进行验证。这些都得注意哦!
第五步，不正规的商店，不要因为某食品的价格低就去那些不正规的商家消费，要明白一个道理便宜没好货。哪怕正规的商店价格稍高，但有质量保证，吃得也会放心更健康一些。
FreeMarker template error:
The following has evaluated to null or missing:
==> zxzx.logo [in template "zixun/mip_baoguang_xiangxi.ftl" at line 232, column 30]
Tip: If the failing expression is known to be legally null/missing, either specify a default value with myOptionalVar!myDefault, or use <#if myOptionalVar??>when-present<#else>when-missing. (These only cover the last step of the expression; to cover the whole expression, use parenthessis: (myOptionVar.foo)!myDefault, (myOptionVar.foo)??
The failing instruction (FTL stack trace):
----------
==> #if zxzx.logo != "" [in template "zixun/mip_baoguang_xiangxi.ftl" at line 232, column 25]
----------
Java stack trace (for programmers):
----------
freemarker.core.InvalidReferenceException: [... Exception message was already printed; see it above ...]
at freemarker.core.InvalidReferenceException.getInstance(InvalidReferenceException.java:98)
at freemarker.core.EvalUtil.compare(EvalUtil.java:230)
at freemarker.core.EvalUtil.compare(EvalUtil.java:148)
at freemarker.core.ComparisonExpression.evalToBoolean(ComparisonExpression.java:103)
at freemarker.core.IfBlock.accept(IfBlock.java:82)
at freemarker.core.Environment.visit(Environment.java:265)
at freemarker.core.MixedContent.accept(MixedContent.java:93)
at freemarker.core.Environment.visitByHiddingParent(Environment.java:286)
at freemarker.core.IteratorBlock$Context.runLoop(IteratorBlock.java:193)
at freemarker.core.Environment.visitIteratorBlock(Environment.java:509)
at freemarker.core.IteratorBlock.accept(IteratorBlock.java:103)
at freemarker.core.Environment.visitByHiddingParent(Environment.java:286)
at freemarker.core.ConditionalBlock.accept(ConditionalBlock.java:86)
at freemarker.core.Environment.visit(Environment.java:265)
at freemarker.core.MixedContent.accept(MixedContent.java:93)
at freemarker.core.Environment.visit(Environment.java:265)
at freemarker.core.Environment.process(Environment.java:243)
at freemarker.template.Template.process(Template.java:277)
at org.springframework.web.servlet.view.freemarker.FreeMarkerView.processTemplate(FreeMarkerView.java:366)
at org.springframework.web.servlet.view.freemarker.FreeMarkerView.doRender(FreeMarkerView.java:283)
at org.springframework.web.servlet.view.freemarker.FreeMarkerView.renderMergedTemplateModel(FreeMarkerView.java:233)
at org.springframework.web.servlet.view.AbstractTemplateView.renderMergedOutputModel(AbstractTemplateView.java:167)
at org.springframework.web.servlet.view.AbstractView.render(AbstractView.java:250)
at org.springframework.web.servlet.DispatcherServlet.render(DispatcherServlet.java:1047)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:817)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:719)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:669)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:574)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:723)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.bbaqw.mip.html.filter.CacheFilter.doFilter(CacheFilter.java:86)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:88)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:76)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at com.bbaqw.mip.util.AppUrlFilter.sendMsite(AppUrlFilter.java:293)
at com.bbaqw.mip.util.AppUrlFilter.doFilter(AppUrlFilter.java:123)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:235)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:103)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:293)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:861)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:606)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:489)
at java.lang.Thread.run(Thread.java:748)