Bun detection

The inspection of steamed buns mainly includes the following aspects:

Ingredient inspection

Filling ingredient inspection
- For steamed buns with meat fillings, the type of meat will be tested, and the polymerase chain reaction (PCR) technology will be used to determine whether it is the labeled pork, beef or other meat varieties to prevent inferior products from being sold as good ones. At the same time, the freshness of the meat will be tested, such as the content of volatile basic nitrogen. The higher the content, the higher the degree of meat corruption may be. The volatile basic nitrogen content of fresh pork generally does not exceed 15mg/100g.

- For steamed buns with vegetable fillings, the pesticide residues of the vegetables will be tested. For example, gas chromatography-mass spectrometry (GC-MS) technology is used to detect organophosphorus pesticide residues. The national standard has clear regulations on the pesticide residue limits of different vegetables to protect the health of consumers.

- Test the additives in the fillings, such as sweeteners (such as sodium saccharin) and preservatives (such as potassium sorbate). The amount of these additives used must comply with the provisions of GB 2760-2014 "National Food Safety Standard Food Additives Use Standard". For example, the maximum amount of sodium saccharin used in steamed bun fillings is 0.15g/kg.

Wrapping ingredient testing
- Test the quality of flour, including gluten content. The gluten content (wet basis) of high-gluten flour is generally 30% - 36%, medium-gluten flour is 28% - 32%, and low-gluten flour is 18% - 24%. The appropriate gluten content can ensure the taste and toughness of steamed bun wrapping.

- Test the additives in the wrapping, such as whitening agents (benzoyl peroxide, etc.), but benzoyl peroxide is now banned in food processing. It will also test whether it contains illegal added substances, such as bleaching block (sodium formaldehyde sulfoxylate), which is an illegal whitening agent.

Microbiological testing

Total colony count test
- Reflects the degree of bacterial contamination of steamed buns. Test in accordance with the national standard GB 4789.2 - 2016 "National Food Safety Standard Food Microbiological Inspection Total Colony Count Determination". Generally speaking, under normal production and processing conditions, the total colony count limit (cfu/g) of steamed buns should meet the corresponding food safety standards. For example, in the sales link, the total colony count is generally required to be no more than 10,000 cfu/g.

Coliform bacteria detection
- This is a fecal contamination indicator bacteria, used to measure the hygienic quality of steamed buns. It is tested using the method of GB 4789.3-2016 "National Food Safety Standard Food Microbiology Inspection Coliform Group Count". The most probable number (MPN)/g of coliform bacteria in qualified steamed bun products should be within the specified range, for example, no more than 100 MPN/g.

Pathogenic bacteria detection
- Focus on detecting pathogenic bacteria such as Salmonella and Staphylococcus aureus. It is carried out in accordance with standards such as GB 4789.4-2016 (Salmonella detection) and GB 4789.10-2016 (Staphylococcus aureus detection). These pathogenic bacteria must not be detected in steamed bun products because they can cause serious foodborne diseases.

Sensory testing

Appearance testing
- The shape of the buns should be complete, uniform in size, without damage or exposed fillings. For example, for common round buns, the circumference should be regular and the pleats should be uniform and beautiful.

Color testing
- The dough should be natural white or wheat color, uniform in color, without abnormal colors such as yellow spots and black spots. The color of the filling should also conform to the color characteristics of the ingredients themselves, such as reddish brown for bean paste filling and bright green for vegetable filling.

Odor and taste testing
- The smell should have the wheat aroma of the buns and the aroma of the fillings, without sour smell, rancid smell or other peculiar smells. In terms of taste, the dough should be soft and elastic, and the fillings should be delicate and pure in taste. For example, meat-filled buns should have a strong meaty aroma, and vegetable-filled buns should have a refreshing vegetable taste.