GB 2731-1988 Ham Hygiene Standard GB2731-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Hygienic Standard of Chinese Ham Subject Content and Scope of Application
This standard specifies the quality and hygienic requirements of commercially available ham. UDC 613. 28
GB 2731-88
Replaces GB2731--81
This standard applies to meat products made from fresh pork hind legs after dry salting, washing, sun drying, fermentation (or without washing, sun drying, fermentation). 2 Reference Standards
GB 5009. 33
GB 5009. 37
3 Sensory Indicators
Determination of Nitrite and Nitrate in Foods Analytical Methods of Hygienic Standards for Edible Vegetable Oils Sensory Indicators See Table 1.
Grade freshness
Tissue state
Smell and
Cooked taste
Physical and chemical indicators
Meat section is deep rose red or pink, fat section is white or slightly red, shiny
Dense and firm, section is flat
Has the unique aroma of ham or a bland aroma. When tasting, the salt taste is moderate, without other peculiar smell
Physical and chemical indicators are shown in Table 2.
Peroxide value (mcq/kg)
Trimethylamine nitrogen (mg/100g)
Industrial nitrate (mg/kg, calculated as NaNO2) test method
5.1 Test method for trimethylamine nitrogen:
Grade freshness
The cut surface of muscle is dark red or deep rose red, and the cut surface of fat is white or light yellow with poor luster
Dense and slightly soft, with a smooth cut surface
With a slight flavor of sauce, fermented black beans or sourness. A slight sour or astringent taste is allowed when tasting.
First-level freshness
Second-level freshness
5.1.1 Principle: Trimethylamine [(CH3)3N is produced by the reduction of trimethylamine oxide [(CH3); NO] in fish and meat products due to the action of bacteria during the corruption process. It is a volatile alkaline nitrogen-containing substance. This substance is extracted into anhydrous toluene and reacts with picric acid to form yellow picric acid trimethylamine salt. Then, color comparison with the standard tube can be performed at the same time to measure the trimethylamine-nitrogen content in the test sample. 5.1.2 Reagents:
5.1.2.1 20% trichloroacetic acid solution.
5.1.2.2 Toluene: Reagent grade, dehydrate with anhydrous sodium sulfate, shake and distill with 1N sulfuric acid to remove interfering substances, and finally dehydrate with anhydrous sodium sulfate to make it dry
5.1.2.3 Picric acid toluene solution:
5.1.2.3.1 Reserve solution: Dissolve 2g of dry picric acid (reagent grade) in 100mL of anhydrous toluene to make it a 2% picric acid toluene solution.
5.1.2.3.2 Application solution: Dilute the reserve solution to 0.02% picric acid toluene solution for application. 5.1.2.4 1:1 potassium carbonate solution.
5.1.2.5 10% formaldehyde solution: First shake formaldehyde (reagent grade, content is 36%38%) with magnesium carbonate and filter, then dilute to 10% concentration.
5.1.2.6 Anhydrous sodium sulfate.
5.1.2.7 Preparation of trimethylamine-nitrogen standard solution: Weigh about 0.5 ml of trimethylamine hydrochloride (reagent grade), dilute to 100 mL, take 5 mL and dilute to 100 mL, and use the micro or semi-micro Kjeldahl distillation method to accurately determine the amount of trimethylamine-nitrogen with the last 5 ml of dilution, and calculate the content per ml, and then dilute to make each ml contain 100ug of trimethylamine-nitrogen, as a stock solution. During the determination, dilute the above stock solution 10 times to make each ml contain more than 10μ of trimethylamine-nitrogen. Accurately pipette 1.0, 2.0, 3.0.4.0, 5.0 mL (equivalent to 10μg, 20μg, 30g, 40ug, 50ug) of the last diluted standard solution into a 25mL MaijelGerson reaction bottle, add distilled water to 5.0 mL, and make a blank at the same time. The following treatments are in accordance with the sample operation method, and the standard curve is prepared by the optical density number. 5.1.3 Apparatus
5.1.3.1 25 mL Maijel Gerson reaction bottle. 5.1.3.2 100 mL or 150 mL glass stoppered flask. 5.1.3.3 100 mL volumetric flask.
5.1.3.4 Test tube.
5.1.3.5 Bo tube.
Micro or semi-micro Kjeldahl distiller.
581 or 72 photoelectric colorimeter.
5.1.4 Operation method:
Sample treatment: Take 20 g of the meat sample to be tested (the sampling amount is determined by the freshness of the sample), cut it into fine pieces, add 70 mL of water and transfer it to the glass stoppered flask 5.1.4.1
, and add 10 mL of 20% trichloroacetic acid, shake, precipitate protein and filter, the filtrate can be used for determination. 5.1.4.2 Determination method: Take 5mL of the above filtrate (it can also be determined according to the freshness of the sample, but water must be added to make up to 5mL) in a MaijelGerson reaction bottle, add 1mL of 10% formaldehyde solution, 10mL of toluene and 3mL of 1:1 potassium carbonate solution, immediately cover the stopper, shake vigorously up and down 60 times, let it stand for 20min, remove the lower water layer, add about 0.5g of anhydrous sodium sulfate for dehydration, and draw out 5mL into a test tube that has been pre-placed with 5mL of 0.02% picric acid toluene solution. Measure the absorbance at 410nm or with a blue filter, and do a blank test. At the same time, measure the above trimethylamine-nitrogen standard solution (equivalent to 10lu, 20ug, 30u, 40μg, 50g) in the same way as above, prepare a standard curve, and calculate the trimethylamine-nitrogen content in the sample according to the following formula. 5.1.5 Calculation:
Wherein: X trimethylamine nitrogen content in meat sample, mg/100g; OD sample optical density;
standard optical density;
standard trimethylamine-nitrogen mass, mg;
W sample mass g;
volume during determination, mL
volume after dilution, mL. bzxZ.net
5.2 Peroxide value:
According to GB5009.37.
Nitrite:
According to GB5009.33.
Additional remarks:
GB 2731-88
This standard was proposed by the Epidemic Prevention Department of the Ministry of Health of the People's Republic of China. This standard was drafted by the Dongyang Municipal Health and Epidemic Prevention Station of Zhejiang Province and the Qujing District Health and Epidemic Prevention Station of Yunnan Province. The main drafter of this standard was Xu Longfu.
This standard is interpreted by the Ministry of Health's Food Hygiene Supervision and Inspection Institute, the technical unit entrusted by the Ministry of Health.
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