Before you take samples, you should know the source, processing, storage, package and shippment of samples. You are required to sterilize the instruments and vessels and operate in a sterile circumstance. Antiseptic is not allowed. Liquid samples should be mixed well before sampling. Solid samples should be taken in different parts so that the sample would be representative. Inspect the samples once they are taken.
The sampling method of food microbiology analysis made by ICMSF has been gradually adopted at home and abroad. Different sampling numbers are stipulated by ICMSF according to the principles as follows:
1. The varying degrees of various microorganisms' damage towards human 2. the damage degrees of food can be divided into three categories after different treatments: the extent of harm decreases; the extent of harm does not change; the extent of harm increases. The sampling method according to ICMSF definites that n means sampling numbers in a batch of products, c means that the number of bacterium in the inspection samples exceeds the limit in this product, m means that the limited number of qualified number of bacterium, M means that limited number of qualified bacterium with additional conditions.
(1) Collected samples should be sent to the food microbiology inspection room. It should not be placed for three hours. If you are far away from the inspection room, you can keep the samples at one to five degree centigrade and prevent it from being frozen so that the bacterium would not be destroyed.
(2) You must fill in the application form carefully for inspectors' reference when you inspect the samples.
(3) Once receiving the inspection sheet, inspectors should register immediately and fill in the serial number. And inspectors should put the microbial analysis of food samples into refrigerator or ice sheet at once and prepare positively to insepct.
Samples should be handled in sterile room. If the frozen samples need to unfreeze in the original vessel, the temperature of unfreezing should be two to five degree centigrade and not be place for over 18 hours, or forty five degree centigrade and over 15 minutes.
(1) solid samples
Take different parts of samples with fungus knife, shear and sterile swabs, cut them into pieces and put them into sterilizing containers. Add some water and mix well to make a suspension with a ratio of one to ten and inspect. Add thrity glass balls into the suspension to balance when handling with the egg products. When handling with raw meat and viscera, you should sterilize the surface and cut off the surface samples, and take the deeper samples.
(2) liquid samples
Disinfect the opening of the bottle of original package samples with alcohol wipes, then cover the opening with gauze which have been disinfected by the phenolic or lysol disinfectant. Open the samples with derailing switch disinfected by flame-sterilization. Shake the bottle well and suck up the liquid with sterile pipette. As for liquid food with carbon dioxide, you should open the bottle according to the above instructions, pour the samples into sterile ground glass bottles, cover it up with sterilized gauze leaving a slit, and shake the bottle slightly so that the gas could come out. Then you can inspect the food microbiology. Put the frozen food into sterile vessels and insepct it after it has melted.
Each index has one or several inspection methods. You can choose the right inspection method according to the different types of food and different inspection purposes. Generally the regular inspection method are the national standards, or the international standards like FAO standard, WHO standard and many more, or standards of food importing countries like American FDA standard, Japan' health ministry standard and European EC standard and many more.
Once the food hygiene inspection room receives the application sheet, inspectors should register immediately and fill in the serial number. And inspectors should put the samples into refrigerator or ice sheet at once according to the inspection rules and prepare positively to insepct the food microbiology.
Generally the positive samples would be handled after they are setting off three days later, which could be longer in special situation. The positive samples of imported foodstuff should be stored for six months and then be handled. The negative samples can be handled at once.
Once the samples of food microbiology has been inspected, inspectors should fill in the report sheet immediately, sign his name and report it to executive, then the executive should verify it with signature and stamping unit seal so that the report comes into force. And the report should be sent to food hygiene supervisors promptly.